Yves Marrocchi

@article{Piralla_etal2023,

title = {A unified chronology of dust formation in the early solar system},

author = {M. Piralla and J. Villeneuve and N. Schnuriger and D. V. Bekaert and Y. Marrocchi},

doi = {10.1016/j.icarus.2023.115427},

year  = {2023},

date = {2023-01-01},

urldate = {2023-01-01},

journal = {Icarus},

volume = {394},

pages = {115427},

abstract = {The chronology of dust formation in the early solar system remains controversial. Chondrules are the most abundant high-temperature objects formed during the evolution of the circumsolar disk. Considering chondrule formation, absolute lead‑lead (Pb--Pb) ages and aluminum‑magnesium (26Al--26Mg) ages relative to calcium‑aluminum-rich inclusions (CAIs) provide inconsistent chronologies, with Pb--Pb ages showing early and protracted chondrule formation episodes whereas 26Al--26Mg ages suggest that chondrule production was delayed by \>1.5 Ma. Here, we develop a new method to precisely determine in situ 26Al--26Mg ages of spinelbearing chondrules, which are not affected by secondary asteroidal processes. Our data demonstrate that 26Al--26Mg chondrule formation ages are actually 1 Ma older than previously thought and extend over the entire lifetime of the disk. This shift in chondrule formation ages relative to CAIs, however, is not sufficient to reconcilethe Pb--Pb and 26Al--26Mg chronologies of chondrule and achondrite formation. Thus, either chondrules’Pb--Pb ages and volcanic achondrites’ 26Al--26Mg ages are incorrect or the age of CAIs should be reevaluated at 4,568.7 Ma to ensure consistency between chronometers. We favor the second hypothesis, given that (i) thecanonical age of CAIs was determined using only 4 specimens and (ii) older ages of 4,568.2 Ma have also been measured. We show that the adoption of 4,568.7 Ma as the new canonical age of CAIs and the use of our new spinel-derived 26Al--26Mg ages enable reconciling the Pb--Pb and 26Al--26Mg ages of chondrules and achondrites.This new chronology implies the existence of a 0.7--1 Ma gap between the formation of refractory inclusions and chondrules, and supports the homogeneous distribution of 26Al in the circumsolar disk.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Marrocchi_etal2023,

title = {Hydrogen isotopic evidence for nebular pre-hydration and the limited role of parent-body processes in CM chondrites},

author = {Y. Marrocchi and T. Rigaudier and M. Piralla and L. Piani},

doi = {10.1016/j.epsl.2023.118151},

year  = {2023},

date = {2023-01-01},

urldate = {2023-01-01},

journal = {Earth and Planetary Science Letters},

volume = {611},

number = {2},

pages = {118151},

abstract = {The conditions and environments in which hydrated phases in unequilibrated meteorites formed remain debated. Among carbonaceous chondrites, Mighei-type chondrites (CMs) display a large range in the degree of aqueous alteration, and thus record different stages of hydration and alteration. Here, we report the bulk H, C, and N contents, H and C isotopic compositions, and thermogravimetric signatures of the most-and least-altered CMs known so far, Kolang and Asuka 12236, respectively. We also report in-situSIMS measurements of the hydrogen isotopic compositions of water in both chondrites. Compared to other CMs, Asuka 12236 has the lowest bulk water content (3.3 wt.% H2O) and the most D-rich water and bulk isotopic compositions ($delta$D =180 and 280 , respectively). Combined with literature data, our results show that phyllosilicate-bearing CMs altered to varying degrees accreted water-ice grains with similar isotopic compositions. These results demonstrate that the hydrogen isotopic variations in CM chondrites (i) are not controlled by secondary alteration processes and (ii) were mostly shaped by interactions between the protoplanetary disk and the molecular cloud that episodically fed the disk over several million years. The minimally altered CM chondrites Paris and Asuka 12236 display peculiar, D-rich, hydrogen isotopic compositions that imply the presence of another H-bearing component in addition to insoluble organic matter and phyllosilicates. This component is most likely the hydrated amorphous silicates that are ubiquitous in these chondrites. CM bulk H and O isotopic compositions are linearly correlated, implying that (i) amorphous silicates in CM matrices were already hydrated by disk processes before the onset of CM parent-body alteration, and (ii) the quest for a hypothetically water-free CM3 is illusory.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Avice_etal2022,

title = {Origin of radiogenic 129Xe variations in carbonaceous chondrites},

author = {G. Avice and M. M. M. Meier and Y. Marrocchi},

doi = {10.7185/geochemlet.2228},

year  = {2022},

date = {2022-01-01},

journal = {Geochemical Perspectives Letters},

volume = {23},

pages = {1--4},

abstract = {Noble gases trapped in primitive meteorites (chondrites) allow quantification of the physical processes that operated during the evolution of the protoplanetary disk (e.g., Kuga et al., 2015). Although these elements are present in different carriers contained in meteorites (including presolar SiC, diamonds, graphite; Ott, 2014), they are mainly hosted in a phase \^{a}ˆ’ referred to as phase Q\^{a}ˆ’ whose nature is still poorly characterised (Busemann et al., 2000). Notwithstanding this uncertainty, it has been shown that phase Q dominates the heavy noble gas budget of chondrites and is closely associated with carbonaceous material that survives HF/HCl attack of bulk meteorites (Lewis et al., 1975). Thanks to its extreme sensitivity to oxidation, the xenon isotopic composition of phaseQhas been precisely determined, revealing a mass dependent isotopic fractionation relative to solar wind (SW-Xe) in favour of the heavy isotopes relative to the light ones (Wieler et al., 1991; Busemann et al., 2000; Gilmour, 2010). However, the commonly used Xe-Q isotopic composition hinges on the average of measurements of several carbonaceous chondrites (CCs) showing distinct Xe isotopic compositions between and within each group, especially for 129Xe (Busemann et al., 2000). Such 129Xe excesses result from the decay of extinct 129I (t1/2 = 16 Myr), which was producing radiogenic 129Xe* during the first \^{a}`u100 million years of the solar system (Jeffery and Reynolds, 1961). The measurement of xenon isotopes in the coma of comet 67P/Churyumov-Gerasimenko revealed extreme 129Xe enrichment relative to 132Xe and the solar composition (Marty et al., 2017). As this large monoisotopic excess would require unlikely 129I enrichment, it has been interpreted as originating from a specific nucleosynthetic process producing 129Xe that was sampled by icy bodies formed in the outer solar system (Marty et al., 2017). Interestingly, the carbon-rich primitive chondrites Tagish Lake and Tarda are thought to originate from D-type asteroids (Hiroi et al., 2001; Marrocchi et al., 2021) considered to have formed at large heliocentric distances beyond the current orbit of Saturn, and potentially as far as the Kuiper Belt (i.e. 30--50 astronomical units = au; Levison et al., 2009). Here we report the results of a comprehensive study of the isotopic compositions of noble gases contained in Tagish Lake and Tarda to evaluate if material accreted in the outer solar system presents specific signatures. We compare our data to other CCs and discuss the origin of the variable radiogenic 129Xe excesses between and within each CC groups.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Marrocchi_etal2022,

title = {Isotopic evidence for two chondrule generations in CR chondrites and their relationships to other carbonaceous chondrites},

author = {Y. Marrocchi and M. Piralla and M. Regnault and V. Batanova and J. Villeneuve and E. Jacquet},

doi = {10.1016/j.epsl.2022.117683},

year  = {2022},

date = {2022-01-01},

journal = {Earth and Planetary Science Letters},

volume = {593},

pages = {117683},

abstract = {Among primitive meteorites, CR chondrites have peculiar isotopic compositions, the origin of which is uncertain and may have involved contributions from primordial molecular cloud material or the chondrites’ formation and agglomeration late during the evolution of the protoplanetary disk. Here, we report a comprehensive textural and isotopic characterization of type I CR chondrules and provide new insights on their formation conditions. We find that two chondrule populations characterized bydifferent sizes and oxygen isotopic compositions co-exist in CR chondrites. The typically larger, 16O-poor (17O \> -4) chondrules (type I-CR chondrules) appear to have formed late out of a CR reservoir already populated by typically smaller, 16O-rich (17O \< -4) chondrules (type I-CO chondrules). Before formation of type I-CR chondrules, the CR reservoir was likely dominated by CI-like dust, in line with the proximity of CR with CI chondrites for many isotopic ratios. The CR reservoir thus may have largely belonged to the continuum shown by other carbonaceous chondrites, although some isotopic ratios maintain some originality and suggest isotopic variation of CI-like dust in the outer disk. Combined with literature data,our data (i) demonstrates that recycling processes are responsible for the singular compositions of CR chondrites and their chondrules for isotopic systems with drastically different geochemical behaviors (O, Cr, Te) and (ii) support the homogeneous distribution of 26Al throughout the protoplanetary disk.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Morin_etal2022,

title = {16O-rich anhydrous silicates in CI chondrites: Implications for the nature and dynamics of dust in the solar accretion disk},

author = {G. L. F. Morin and Y. Marrocchi and J. Villeneuve and E. Jacquet},

doi = {10.1016/j.gca.2022.06.017},

year  = {2022},

date = {2022-01-01},

journal = {Geochimica et Cosmochimica Acta},

volume = {332},

pages = {203--219},

abstract = {CI chondrites have nonvolatile chemical compositions closely resembling that of the Sun’s photosphere and are thus considered to have the most primitive compositions of all known solar system materials. They have, however, experienced pervasive parent-body alteration processes that transformed their primary constituents, obscuring the nature and origin of primordial CI dust. We used in-situ quantitative microprobe and secondary ion mass spectrometry techniques to characterize the chemistry and oxygen isotopic compositions of anhydrous silicates in two sections of the CI chondrites Ivuna and Alais, which contain higher abundances of those than other CI samples. These silicates are Mg-rich olivine and low-Ca pyroxene crystals mostly occurring as aggregates within sub-mm Fe-rich clasts. Our data reveal mass-independent oxygen isotopic variations with D17O values ranging from -23.63 to -0.57texttenthousand, representing the first evidence of extremely 16O-rich (D17O \< -20texttenthousand) olivine and pyroxene grains in CI chondrites. Two of these olivines are characterized by MnO/FeO textasciitilde 1,typical of low-iron, Mn-enriched silicates commonly observed in amoeboid olivine aggregates. Other anhydrous silicate grains have D17O values ranging from -6 to 0texttenthousand, probably representing chondrule fragments. Combined, these results indicate that chondrule and refractory inclusion material were incorporated into the CI parent body(ies). This conclusion is consistent with recent models showing that refractory inclusions could have formed and/or been transported at larger heliocentric distances than previously thought during the concomitant injection of material from the molecular cloud and outward extension of the disk by viscous spreading. The CI chondrules are presumably of local origin, with their isotopic systematics suggesting an affinity with the CR clan.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Pinto_etal2022,

title = {Formation of chondrule fine-grained rims from local nebular reservoirs},

author = {G. Pinto and Y. Marrocchi and E. Jacquet and F. Olivares},

doi = {10.1111/maps.13812},

year  = {2022},

date = {2022-01-01},

journal = {Meteoritics \& Planetary Science},

volume = {57},

number = {5},

pages = {1004--1017},

abstract = {Chondrules are commonly surrounded by fine-grained rims (FGRs) whose origin remains highly debated ; both nebular and parent body settings are generally proposed. Deciphering their origin, however, is of fundamental importance as they could clarify the matrix--chondrule relationship and thus constrain the formation and transport conditions of chondrules in the circumsolar disk. Here, we report a systematic survey of FGRs in CO, CM, CV, and CR chondrites ; we compare (i) the thickness of FGRs to the size of their host chondrules and (ii) the frequency of FGRs to the modal abundance of matrix in the respective host chondrites. Although FGRs show textural variations depending on the petrologic type of the considered chondrites, our data show a positive correlation between apparent rim thickness and the radius of the host chondrule in all chondrite groups. We also found a positive correlation between the evaluated percentages of rimmed chondrules and the modal abundance of matrix material in the chondrites. We show that this relationship could not result from parent body processes, whether matrix compaction or FGR fragmentation. Therefore, we propose that FGRs were accreted under warm conditions at the end of chondrule-forming events. Our results thus support (i) a nebular origin for FGR, whose abundances are directly related to the abundance of available dust in regions of chondrite accretion ; and (ii) the accretion of chondrites from locally formed chondrules and matrix, suggesting limited radial transport in the protoplanetary disk.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Regnault_etal2022,

title = {Oxygen isotope systematics of chondrules in Rumuruti chondrites : Formation conditions and genetic link with ordinary chondrites},

author = {M. Regnault and Y. Marrocchi and M. Piralla and J. Villeneuve and V. Batanova and N. Schnuriger and E. Jacquet},

doi = {10.1111/MAPS.13778},

year  = {2022},

date = {2022-01-01},

journal = {Meteoritics \& Planetary Science},

volume = {57},

number = {1},

pages = {122--135},

abstract = {Rumurutiites (R chondrites) are rare, highly oxidized chondrites belonging to the noncarbonaceous superclan and characterized by low chondrule abundances. Although textural and chemical features of Rumurutiite chondrules resemble those of ordinary chondrites (OCs), their formation conditions and potential genetic link remain debated. Here, we report high-resolution elemental X-ray mapping analyses and in situ O isotopic measurements of olivine grains from five chondrules and eight isolated olivine grains (IOGs) in the NWA 12482 R3 chondrite. The chondrules show chemical zonings similar to their counterparts in ordinary and carbonaceous chondrites (CCs), implying that gas--melt interaction processes between chondrule precursors and SiO- and Mg-rich gas were operative throughout the circumsolar disk. Our isotopic data show that R chondrules are isotopically similar to ordinary chondrules, although differences in their abundances of relict olivine grains and chondrule textural characteristics suggest different formation environments, with R chondrules being formed from 16O-poorer precursors. As with chondrules in OCs, the O isotopic characteristics of R chondrules and IOGs suggest limited transport between CC and noncarbonaceous reservoirs.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Schnuriger_etal2022,

title = {Spinel in CV chondrules : Investigating precursor legacy and chondrule thermal histories},

author = {N. Schnuriger and C. Cartier and J. Villeneuve and V. Batanova and M. Regnault and Y. Marrocchi},

doi = {https://doi.org/doi:10.1111/maps.13802},

year  = {2022},

date = {2022-01-01},

journal = {Meteoritics \& Planetary Science},

volume = {57},

number = {5},

pages = {1018--1037},

abstract = {In carbonaceous chondrites, Mg-spinel (MgAl2O4) grains are ubiquitous in refractory inclusions but rarely reported in chondrules, where they may correspond to minerals either (i) inherited from chondrule precursors or (ii) crystallized from chondrule melts. Here, we report high-current quantitative electron microprobe measurements and secondary ion mass spectrometry oxygen isotopic analyses of Mg-spinel-bearing chondrules in the CV3 carbonaceous chondrites Northwest Africa 10235 and Allende. Compared to spinels in refractory inclusions, chondrule spinels are characterized by higher Cr contents and 16O-poorer oxygen isotopic signatures ($Delta$17O \^{a}‰¡ $delta$17O\^{a}ˆ’0.52 texttimes $delta$18O, from \^{a}ˆ’2 to \^{a}ˆ’6texttenthousand). Because the similar $Delta$17O values of chondrule olivine and spinel crystals imply their comagmatic origin, we applied a geothermometer based on the Al-Cr distribution between these minerals to determine their crystallization temperatures. The calculated temperatures range from 1200 to 1640 textdegreeC (mean = 1470 textdegreeC), most being lower than the estimated liquidus temperature of porphyritic chondrules ( 1600 textdegreeC). Our results suggest that chondrules experienced relatively slow cooling rates (slower than a few hundreds of textdegreeC h\^{a}ˆ’1), which is in good agreement with models of chondrule formation invoking nonlinear or twostage cooling rates.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Marrocchi+Beck2022,

title = {The quest for the water},

author = {Y. Marrocchi and P. Beck},

doi = {10.2138/gselements.18.3.149},

year  = {2022},

date = {2022-01-01},

journal = {Elements},

volume = {18},

pages = {149--153},

abstract = {Water played a key role in shaping the Solar System---from the formation of early solids to the processes of planetary and moon formation. The presence of water in molecular clouds influences the initial abundance and distribution of water in the circumsolar disk, which, in turn, affected the water budget of the terrestrial planets and, therefore, their geological activity and habitability. On Earth, surficial and deep-water cycles have largely governed the planet’s geodynamical and geochemical evolution. This issue focuses on the past and present distribution of water within the Solar System and how this important molecule affects astrophysical and geological processes.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Gaillard_etal2022,

title = {Redox controls during magma ocean degassing},

author = {F. Gaillard and F. Bernadou and M. Roskosz and A. Bouhif and Y. Marrocchi and G. Iacono-Marziano and M. Moreira and B. Scaillet and G. Rogerie},

doi = {10.1016/j.epsl.2021.117255},

year  = {2022},

date = {2022-01-01},

journal = {Earth and Planetary Science Letters},

volume = {577},

number = {22},

pages = {117255},

abstract = {Nitrogen, carbon, hydrogen and sulfur are essential elements for life and comprise about 1% of terrestrial planet masses. These elements dominate planetary surfaces due to their volatile nature, but the Earth’s interior also constitutes a major C-H-N-S reservoir. Resolving the origin of the surficial versus deep volatile reservoirs requires the past 4.5 Giga-years of mantle outgassing and ingassing processes to be reconstructed, involving many unknowns. As an alternative, we propose to define the primordial distribution of volatiles resulting from degassing of the Earth’s magma ocean (MO). The equilibrium partitioning of C-H-O-N-S elements between the MO and its atmosphere is calculated by means of solubility laws, extrapolated to high temperatures and over a large range of redox conditions. Depending on the redox conditions, the amount of volatiles, and the size of the MO considered, we show that the last MO episode may have degassed 40-220 bar atmospheres, whereas hundreds to thousands of ppm of C-H-O-N-S can be retained in the magma. Two contrasting scenarios are investigated: reduced vs. oxidized MO. For reduced cases (\<IW−2), an H-C textpmN-rich atmosphere can be formed, whereas the atmosphere under oxidizing conditions (\>IW +2) would be dry and C-N-S-rich. An intermediate redox state produces a C-N atmosphere. In many cases, the present-day surficial abundances (atmosphere +ocean +crust) of C and N, the most volatile elements, are very close to the calculated primordial MO -atmosphere distribution. This probably means that lithospheric recycling and post-magma ocean degassing only moderately alter the surficial abundances of these elements. Sulfur, in contrast, must have been mostly outgassed by post-MO events. Changes in redox conditions during magma ocean degassing played a first order role in the composition of the primordial atmosphere of planets. We suggest that the more oxidized conditions on Venus due to H-loss may have played a role in the growth of a dry MO atmosphere on this planet compared to an H-bearing one on Earth. To verify these first order assertions, constraints on volatile behaviorunder extreme magma ocean conditions and upon magma ocean solidification are urgently needed.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Krmer-Ruggiu_etal2022,

title = {Detection of incipient aqueous alteration in carbonaceous chondrites},

author = {L. Kr\"{a}mer-Ruggiu and B. Devouard and J. Gattacceca and L. Bonal and H. Leroux and J. Eschrig and D. Borschneck and A. J. King and P. Beck and Y. Marrocchi and V. Debaille and R. D. Hanna and O. Grauby},

doi = {10.1016/j.gca.2022.09.020},

year  = {2022},

date = {2022-01-01},

journal = {Geochimica et Cosmochimica Acta},

volume = {336},

pages = {308--331},

abstract = {We discuss if the detection of aqueous alteration depends on the techniques that are used. We apply different methods to estimate the extent of aqueous alteration on four ungrouped carbonaceous chondrites showing limited aqueous alteration and thermal metamorphism: Chwichiya 002, El M\'{e}dano (EM) 200, Northwest Africa (NWA) 12957 and NWA 11750, classified as C3 or C3.00-ung. The aim is to propose a reliable methodology to identify the most primitive chondrites. Chwichiya 002, NWA 11750 and NWA 12957 display very primitive matrices and could be amongst the most primitive chondrites currently known, similar to the least altered lithologies of the CM chondrites Paris (CM2.9) and Asuka (A) 12085 (CM2.8), A 12236 (CM2.9) and A 12169 (CM3.0). The structure of organic matter and Cr2O3 in ferroan olivines show that the four meteorites have been less heated than the least metamorphosed standard/reference type 3 chondrite, Semarkona (LL3.00), with Chwichiya 002, NWA 12957 and NWA 11750 similar to the CO3.0 s, Acfer 094 (C2-ung) and Paris meteorites. Chwichiya 002 and NWA 12957 show similar alteration phases and degree of alteration, with high abundances of amorphous material with embedded metal and sulfide, resembling Glass with Embedded Metal and Sulfide (GEMS)-like materials, and tochilinite-cronstedtite intergrowths (TCIs) as the major alteration phases. The matrix in NWA 11750 contains aggregates of nanoscale olivine crystals and abundant carbonates, observed as micrometer-sized carbonate veins surrounding chondrules, and as nanoscale carbonates mixed with the fine-grained materials. It also contains abundant grains of metal and a low abundance of phyllosilicates. El Medano 200 shows a high abundance of magnetite (\^{a}`u10 vol%), nanoscale phyllosilicates, troilite, and organic matter. The variability of the secondary alteration phases in the meteorites suggests different alteration mechanisms, likely depending on both the starting composition of the meteorites and the composition of the fluids of alteration.Scanning and transmission electron microscopy (SEM and TEM) allow the identification of primitive phases and the composition and spatial distribution of the secondary phases. X-ray diffraction (XRD) can detect alteration products, including some amorphous phases, although this is limited by the small coherence domains of small TCIs and other phyllosilicates. Transmission infrared (IR) spectroscopy can detect phyllosilicate and carbonate, but is ineffective for the detection of amorphous phases, metal, or sulfide. Both matrix defocused electron microprobe analyses (EMPA) and thermogravimetric analysis (TGA) allow detection of hydrated minerals, such as phyllosilicates and carbonates, but are strongly influenced by the presence of organic matter and do not reflect the overall alteration state of a meteorite. We conclude that the assessment of the primitivity of a chondrite is highly technique dependent. We propose a combination of XRD and the Cr2O3 in ferroan olivines or Raman spectroscopy for a rapid characterization of the alteration state of a chondrite and the detection of the most primitive meteorites. Finally, the combination of XRD and TEM allows for the detection of all primary and secondary phases and represents an ideal methodology for the characterization and detailed study of primitive chondrites and the different types of incipient aqueous alteration.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Kerraouch_etal2022,

title = {Heterogeneous nature of the carbonaceous chondrite breccia Aguas Zarcas -- Cosmochemical characterization and origin of new carbonaceous chondrite lithologies},

author = {I. Kerraouch and Y. Kebukawa and A. Bischoff and M. E. Zolensky and E. W\"{o}lfer and J. L. Hellmann and M. Ito and A. King and M. Trieloff and J. A. Barrat and P. Schmitt-Kopplin and A. Pack and M. Patzek and R. D. Hanna and T. Fockenberg and Y. Marrocchi},

doi = {10.1016/j.gca.2022.07.010},

year  = {2022},

date = {2022-01-01},

urldate = {2022-01-01},

journal = {Geochimica et Cosmochimica Acta},

volume = {334},

pages = {155--186},

abstract = {On April 23rd, 2019, the Aguas Zarcas meteorite fall occurred in Costa Rica. Because the meteorite was quickly recovered, it contains valuable extraterrestrial materials that have not been contaminated by terrestrial processes. Our X-ray computed tomography (XCT) and scanning electron microscopy (SEM) results on various pre-rain fragments from earlier work (Kerraouch et al., 2020; 2021) revealed several distinct lithologies: Two distinct metal-rich lithologies (Met-1 and Met-2), a CM1/2 lithology, a C1 lithology, and a brecciated CM2 lithology consisting of different petrologic types. Here, we further examined these lithologies in the brecciated Aguas Zarcas meteorite and report new detailed mineralogical, chemical, isotopic, and organic matter characteristics. In addition to petrographic differences, the lithologies also display different chemical and isotopic compositions. The variations in their bulk oxygen isotopic compositions indicate that the various lithologies formed in different environments and/or under diverse conditions (e.g., water/rock ratios). Each lithology experienced a different hydration period during its evolution. Together, this suggests that multiple precursor parent bodies may have been involved in these processes of impact brecciation, mixing, and re-assembly. The Cr and Ti isotopic data for both the CM1/2 and Met-1 lithology are consistent with those of other CM chondrites, even though Met-1 displays a significantly lower e50Ti isotopic composition that may be attributable to sample heterogeneities on the bulk meteorite scale and may reflect variable abundances of refractory phases in the different lithologies of Aguas Zarcas. Finally, examination of the organic matter of the various lithologies also suggests no strong evidence of thermal events, but a short-term heating cannot completely be excluded. Raman parameters indicate that the peak temperature has been lower than that for Yamato-793321 (CM2, textasciitilde 400 textdegreeC). Considering the new information presented in this study, we now better understand the origin and formation history of the Aguas Zarcas daughter body.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Rudraswami_etal2022,

title = {In-situ O-isotope analysis of relict spinel and forsterite in small (\<200 $mu$m) Antarctic micrometeorites -- Samples of chondrules \& CAIs from carbonaceous chondrites},

author = {N. G. Rudraswami and M. D. Suttle and Y. Marrocchi and S. Taylor and J. Villeneuve},

doi = {10.1016/j.gca.2022.03.015},

year  = {2022},

date = {2022-01-01},

journal = {Geochimica et Cosmochimica Acta},

volume = {325},

pages = {1--24},

abstract = {We report high-precision secondary ion mass spectrometer triple oxygen isotope systematics (95 individual analyses) from 37 micrometeorites (MMs) collected from South Pole Water Well (SPWW), Antarctica. The study population focuses on unmelted coarse-grained (Cg) MMs (n = 23) with both multiple (n = 14) and single-mineral (n = 9) varieties investigated. We also analysed relict minerals in porphyritic cosmic spherules (n = 13) and the relict matrix in a single scoriaceous fine-grained (Fg) MM. The target minerals investigated are primarily olivine (Fo \^{a}`u 43--99%) and spinel. Textural, chemical and isotopic data confirm that both olivine and spinel grains have retained their pre-atmospheric O-isotope compositions, allowing inferences to be drawn about their formation and parent body affinities. We separate the study population into three groups: spinel-free particles (consisting of the CgMMs and PO cosmic spherules), spinel-bearing MMs and the single FgMM.Olivine grains in spinel-free MMs vary between $delta$17O: \^{a}ˆ’12.6texttenthousand and +3.5texttenthousand, $delta$18O: \^{a}ˆ’9.6texttenthousand and +7.5texttenthousand, and $Delta$17O: \^{a}ˆ’9.5texttenthousand and +1.3texttenthousand and define a slope-1 profile in $delta$18O--$delta$17O isotope space. They are most likely fragmented chondrules, with both type I and type II varieties represented. Their observed Mg#-$Delta$17O distribution is best explained by a mixture of CM chondrules and either CR chondrules, Tagish Lake chondrules or WILD2 cometary silicates. One of these chondrule-like MMs has an isotopically heterogeneous composition, characterised by a single olivine grain with a markedly 16O-rich composition ($Delta$17O: \^{a}ˆ’16.3texttenthousand), suggesting it is a relict silicate fragment of AOA material that was incorporated into the chondrule precursor.We analysed 11 spinel grains in five spinel-bearing MMs. In all instances spinels are nearly pure MgAl2O4 with isotopically light (16O-rich) compositions (ranging from $delta$17O: \^{a}ˆ’34.4texttenthousand to \^{a}ˆ’0.9texttenthousand, $delta$18O: \^{a}ˆ’30.8texttenthousand to +11.0texttenthousand, and $Delta$17O: \^{a}ˆ’18.3texttenthousand to \^{a}ˆ’4.4texttenthousand). They are therefore 16O-poor relative to spinel found in unaltered CAIs, indicating a different origin. Grains with high Cr2O3 contents (\>0.5 wt.%) are interpreted originating from Al-rich chondrule precursors, while low Cr2O3 spinels (\<0.5 wt.%) are interpreted as CAI-derived material affected by parent body aqueous alteration.Finally, we report a single FgMM with a 16O-poor composition ($Delta$17O \> 0texttenthousand and $delta$18O \> +15.0texttenthousand). This particle adds to our growing inventory of water-rich C-type asteroid samples united by their formation history which is characterised by accretion of abundant heavy water.Our work strongly supports findings from earlier in-situ O-isotope studies, concluding that small MMs overwhelmingly sample material from CC parent bodies and that CgMMs largely sample chondrules and, to a lesser extent, CAI material. The analysis of CgMMs therefore provides insights into the primitive O-isotope reservoirs that were present in the early solar system and how they interacted.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Bernadou_etal2021,

title = {Nitrogen solubility in basaltic silicate melt ?\u{I} Implications for degassing processes},

author = {F. Bernadou and F. Gaillard and E. F\"{u}ri and Y. Marrocchi and A. Slodczyk},

doi = {10.1016/j.chemgeo.2021.120192},

year  = {2021},

date = {2021-01-01},

journal = {Chemical Geology},

volume = {573},

pages = {120192},

abstract = {The distribution of nitrogen between the different terrestrial reservoirs (core-mantle-atmosphere) and how this may have changed since the earliest planetary stages is uncertain. In particular, the primordial degassing processes of the magma ocean and its role in the formation of the atmosphere remains to be quantified. Since no geological samples can capture this early degassing process, we need to go through the thermodynamic modeling of the nitrogen solubility in silicate melt. We hence performed experiments on basaltic samples at fluid saturation in the C-H-O-N system, using an Internally Heated Pressure Vessel (IHPV) and Piston Cylinder (PC) in the pressure range 0.8 kbar to 10 kbar, temperature between 1200 and 1300 ◦C, and a wide range of fO2 conditions from IW + 4.9 to IW-4.7 (IW standing for the Iron-Wustite redox buffer). The nitrogen concentration in the quenched silicate melts at fluid saturation was analysed by secondary ion mass spectrometry (SIMS), and the speciation of the dissolved C-O-H species was determined by Fourier transform infrared spectroscopy (FTIR). We identified two nitrogen species in the silicate melt : N2 dominating at fO2 \> IW and N3- at lower fO2. Using these data and a database constraining nitrogen concentration at fluid saturation from 1 bar to 10 kbar pressure, we calibrated a solubility law for nitrogen in basalts defining its P-T-fO2 dependences. This model expands the model of Libourel et al. (2003) to high pressure and higher C-O-H activities. It can be used to investigate the nitrogen degassing processes for different pressure, temperature and fO2 conditions relevant to planetary accretion and modern volcanism.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Bouden_etal2021,

title = {Triple oxygen isotope measurements by multi-collector secondary ion mass spectrometry},

author = {N. Bouden and J. Villeneuve and Y. Marrocchi and E. Deloule and E. F\"{u}ri and A. Gurenko and L. Piani and E. Thomassot and P. Peres and F. Fernandes},

doi = {doi: 10.3389/feart.2020.601169},

year  = {2021},

date = {2021-01-01},

journal = {Frontiers in Earth Science},

pages = {8:601169},

abstract = {Secondary ion mass spectrometry (SIMS) is a powerful technique for in situ triple oxygen isotope measurements that has been used for more than 30 years. Since pioneering works performed on small-radius ion microprobes in the mid-80s, tremendous progress has been made in terms of analytical precision, spatial resolution and analysis duration. In this respect, the emergence in the mid-90s of the large-radius ion microprobe equipped with a multi-collector system (MC-SIMS) was a game changer. Further developments achieved on CAMECA MC-SIMS since then (e.g., stability of the electronics, enhanced transmission of secondary ions, automatic centering of the secondary ion beam, enhanced control of the magnetic field, 1012$\Omega$ resistor for the Faraday cup amplifiers) allow nowadays to routinely measure oxygen isotopic ratios (18O/16O and 17O/16O) in various matrices with a precision (internal error and reproducibility) better than 0.5texttenthousand (2$sigma$), a spatial resolution smaller than 10 $mu$m and in a few minutes per analysis. This paper focuses on the application of the MC-SIMS technique to the in situ monitoring of mass-independent triple oxygen isotope variations.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Boulliung_etal2021,

title = {Nitrogen diffusion in silicate melts under reducing conditions},

author = {J. Boulliung and C. Dalou and L. Tissandier and E. F\"{u}ri and Y. Marrocchi},

doi = {10.2138/am-2021-7799CCBYNCND},

year  = {2021},

date = {2021-01-01},

journal = {American Mineralogist},

volume = {106},

pages = {662--666},

abstract = {The behavior of nitrogen during magmatic degassing and the potential kinetic fractionation between N and other volatile species (H, C, O, noble gases) are poorly known due to the paucity of N diffusion data in silicate melts. To better constrain N mobility during magmatic processes, we investigated N diffusion in silicate melts under reducing conditions. We developed uniaxial diffusion experiments at 1 atm, 1425 textdegreeC, and under nominally anhydrous reducing conditions (fO2 ≤ IW-5.1, where IW is oxygen fugacity, fO2, reported in log units relative to the iron-wüstite buffer), in which N was chemically dissolved in silicate melts as nitride (N3--). Although several experimental designs were tested (platinum, amorphous graphite, and compacted graphite crucibles), only N diffusion experiments at IW-8 in compacted graphite crucibles for simplified basaltic andesite melts were successful. Measured N diffusivity (DN) is on the order of 5.3 textpm 1.5 texttimes 10--12 m2 s--1, two orders of magnitude lower than N chemical diffusion in soda-lime silicate melts (Frischat et al. 1978). This difference suggests that nitride diffusivity increases with an increasing degree of melt depolymerization. The dependence of N3-- diffusion on melt composition is greater than that of Ar. Furthermore, N3-- diffusion in basaltic-andesitic melts is significantly slower than that of Ar in similarly polymerized andesitic-tholeiitic melts at magmatic temperatures (1400--1450 textdegreeC ; Nowak et al. 2004). This implies that N/Ar ratios can be fractionated during reducing magmatic processes, such as during early Earthtextquoterights magma ocean stages.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Jacquet_etal2021,

title = {Origin of isolated olivine grains in carbonaceous chondrites},

author = {E. Jacquet and M. Piralla and P. Kersaho and Y. Marrocchi},

doi = {doi: 10.1111/maps.13583},

year  = {2021},

date = {2021-01-01},

journal = {Meteoritics \& Planetary Science},

volume = {56},

number = {1},

pages = {13--33},

abstract = {We report microscopic, cathodoluminescence, chemical, and O isotopic measurements of FeO-poor isolated olivine grains (IOG) in the carbonaceous chondrites Allende (CV3), Northwest Africa 5958 (C2-ung), Northwest Africa 11086 (CM2-an), and Allan Hills 77307 (CO3.0). The general petrographic, chemical, and isotopic similarity with bona fide type I chondrules confirms that the IOG derived from them. The concentric CL zoning, reflecting a decrease in refractory elements toward the margins, and frequent rimming by enstatite are taken as evidence of interaction of the IOG with the gas as standalone objects. This indicates that they were splashed out of chondrules when these were still partially molten. CaO-rich refractory forsterites, which are restricted to $Delta$17O \<-4textdegree/textdegreetextdegree likely escaped equilibration at lower temperatures because of their large size and possibly quicker quenching. The IOG thus bear witness to frequent collisions in the chondrule-forming regions.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Marrocchi_etal2021,

title = {The Tarda meteorite: A window into the formation of D-type asteroids},

author = {Y. Marrocchi and G. Avice and J. A. Barrat},

doi = {10.3847/2041-8213/abfaa3},

year  = {2021},

date = {2021-01-01},

journal = {Tha Astrophysical Journal Letters},

volume = {913},

number = {L9},

abstract = {Dynamic models of solar system evolution suggest that D-type asteroids formed beyond Saturnʼs orbit and represent invaluable witnesses of the prevailing conditions in the outer solar system. Here, we report a comprehensive petrographic and isotopic characterization of the carbonaceous chondrite Tarda, a recent fall recovered in the Moroccan Sahara. We show that Tarda shares strong similarities with the D-type-derived chondrite Tagish Lake, implying that Tarda represents a rare sample of D-type asteroids. Both Tarda and Tagish Lake are characterized by the presence of rare 16O-rich chondrules and chondrule fragments, high C/H ratios, and enrichments in deuterium, 15N, and 13C. By combining our results with literature data on carbonaceous chondrites related to C-type asteroids, we show that the outer solar system 4.56 Gy ago was characterized by largescale oxygen isotopic homogeneities in (i) the water--ice grains accreted by asteroids and (ii) the gas controlling the formation of FeO-poor chondrules. Conversely, the zone in which D-type asteroids accreted was significantly enriched in deuterium relative to the formation regions of C-type asteroids, features likely inherited from unprocessed, D-rich, molecular-cloud materials.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Marrocchi_etal2021_2,

title = {The astrophysical context of collision processes in meteorites},

author = {Y. Marrocchi and M. Delbo and M. Gounelle},

doi = {10.1111/maps.13716},

year  = {2021},

date = {2021-01-01},

journal = {Meteoritics \& Planetary Science},

volume = {56},

number = {7},

pages = {1406--1421},

abstract = {Chondrites are leftover solids from the early evolution of the solar protoplanetary disk that never experienced melting since their formation. They comprise unequilibrated assemblages of low- and high-temperature components, including volatile-rich, fine-grained matrices, Fe-Ni metal, sulfides, refractory inclusions, and chondrules. Consequently, chondrites are commonly described as pristine, primitive, or primordial rocks of the solar system. However, impact-generated secondary features are abundant in chondrites, suggesting that collisions among early-formed planetesimals and their fragmentation and reassembly have been effective throughout the evolution of the solar system. In this report, we review evidence of the major role of impacts in generating the current mineralogical and petrographic characteristics of chondrites. We provide perspective to these meteoritic features by discussing recent analyses of large-scale structures of the main asteroid belt and remote-sensing observations of asteroids. Observations at various spatial scales all attest that the textquotelefttextquoteleftprimitivetextquoterighttextquoteright materials formed during the evolution of the solar system have largely been reprocessed, confirming previous studies that primitivity is relative, not absolute. This implies that (1) chondrites (and some differentiated meteorites) should systematically be envisioned as reprocessed and heterogeneous materials and (2) brecciated meteorites should be considered the norm and unbrecciated meteorites the exception.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Pinto_etal2021,

title = {Constraints on planetisimal accretion inferred from particle-size distribution in CO chondrites},

author = {G. A. Pinto and Y. Marrocchi and A. Morbidelli and S. Charnoz and M. E. Varela and K. Soto and R. Martinez and F. Olivares},

doi = {10.3847/2041-8213/ac17f2},

year  = {2021},

date = {2021-01-01},

journal = {The Astrophysical Journal Letters},

volume = {917},

number = {L25},

abstract = {The formation of planetesimals was a key step in the assemblage of planetary bodies, yet many aspects of their formation remain poorly constrained. Notably, the mechanism by which chondrules---submillimetric spheroids that dominate primitive meteorites---were incorporated into planetesimals remains poorly understood. Here we classify and analyze particle-size distributions in various CO carbonaceous chondrites found in the Atacama Desert. Our results show that the average circle-equivalent diameters of chondrules define a positive trend with the petrographic grade, which reflects the progressive role of thermal metamorphism within the CO parent body. We show that this relationship could not have been established by thermal metamorphism alone but rather by aerodynamic sorting during accretion. By modeling the self-gravitational contraction of clumps of chondrules, we show that (i) the accretion of the CO parent body(ies) would have generated a gradual change of chondrule size with depth in the parent body, with larger chondrules being more centrally concentrated than smaller ones, and (ii) any subsequent growth by pebble accretion would have been insignificant. These findings give substantial support to the view that planetesimals formed via gravitational collapse.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Piralla_etal2021,

title = {Apatite halogen and hydrogen isotope constraints on the conditions of hydrothermal alteration in carbonaceous chondrites},

author = {M. Piralla and R. Tart`ese and Y. Marrocchi and K. H. Joy},

doi = {10.1111/maps.13639},

year  = {2021},

date = {2021-01-01},

journal = {Meteoritics \& Planetary Science},

volume = {56},

number = {4},

pages = {809--828},

abstract = {Apatite has been widely used for assessing the volatile inventory and hydrothermal fluid compositions of asteroidal and planetary bodies. We report the OH, F, and Cl abundances, as well as the hydrogen isotope composition, of apatite in the CM1-2 chondrite Boriskino and in the C1-ungrouped Bench Crater meteorite. Apatite in both meteorites is halogen-poor, close to the hydroxylapatite endmember composition, and characterized by average $delta$DSMOW values of −226 +-59% and 233 +-92%, respectively. Compared to apatite, the matrix in Bench Crater is depleted in D with a $delta$DSMOW value of −16 +-119texttenthousand. Comparing apatite and water H isotope compositions yields similar apatite-water D/H fractionation $Delta$DApatite-Water of approximately 120--150texttenthousand for both chondrites, suggesting that apatite formed at similar temperatures. Combining a lattice strain partitioning model with apatite F and Cl abundances in Boriskino and Bench Crater yields low F and Cl abundances \<300 $mu$g g−1 in apatite-forming fluids, and fluid F/Cl ratios that are roughly consistent with the bulk F/Cl ratios of other CI and CM chondrites. This suggests that hydrothermal alteration on these meteorite parent bodies took place under closed-system conditions. Based on the OH abundance estimates for the apatite-forming fluids, we estimated the pH values of alteration fluids to be of approximately 10--13. Such alkaline fluid compositions are consistent with previous modeling and suggest that apatite formed late, toward the end of completion of hydrothermal alteration processes on the Boriskino and Bench Crater parent bodies},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Piralla_etal2021_2,

title = {Conditions of chondrule formation in ordinary chondrites},

author = {M. Piralla and J. Villeneuve and V. Batanova and E. Jacquet and Y. Marrocchi},

doi = {10.1016/j.gca.2021.08.007},

year  = {2021},

date = {2021-01-01},

journal = {Geochimica et Cosmochimica Acta},

volume = {313},

pages = {295--312},

abstract = {Chondrules are sub-millimetric spheroids that are ubiquitous in chondrites and whose formation mechanism remains elusive. Textural and oxygen isotopic characteristics of chondrules in carbonaceous chondrites (CCs) suggest that they result from the recycling of isotopically heterogeneous early-condensed precursors via gas--melt interactions. Here, we report high-resolution X-ray elemental maps and in situ O isotopic analyses of FeO-poor, olivine-rich chondrules from ordinary chondrites (OCs) to compare the conditions of chondrule formation in these two main classes of chondrites. OC chondrules show minor element (e.g., Ti, Al) zonings at both the chondrule and individual olivine grain scales. Considering the entire isotopic data set, our data define a mass-independent correlation, with olivine grains showing O isotopic variations spanning more than 40texttenthousand. Though 16O-rich relict olivine grains were identified in OC chondrules, they are much less abundant than in CC chondrules. They appear as two types : (i) those with low minor element abundances and D17O \< -15texttenthousand and (ii) those with varying minor element abundances and less negative D17O values averaging -5.5texttenthousand. The host olivine grains exhibit massdependent O isotopic variations within individual chondrules. Our results reveal that similar processes (precursor recycling and interactions between chondrule melts and a SiO- and Mg-rich gas) established the observed features of OC and CC chondrules. The mass-dependent isotopic variations recorded by host olivine grains result from kinetic effects induced by complex evaporation/recondensation processes during the gasmelt interactions. This suggests that OC chondrules formed through enhanced recycling processes, in good agreement with the lower abundances of relict olivine grains in OC chondrules compared to CC chondrules. We use the D18O = d18O ?\u{I} d17O parameter to demonstrate that there is no genetic relationship between CC and OC chondrules, suggesting limited radial transport in the protoplanetary disk. Finally, to the first order, the D18O--D17O diagram may allow the non-carbonaceous vs. carbonaceous origin of a given chondrule to be deciphered.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Piani_etal2021,

title = {Origin of hydrogen isotopic variations in chondritic water and organics},

author = {L. Piani and Y. Marrocchi and L. G. Vacher and H. Yurimoto and M. Bizzarro},

doi = {10.24396/ORDAR-61},

year  = {2021},

date = {2021-01-01},

urldate = {2021-01-01},

journal = {Earth and Planetary Science Letters},

pages = {117008},

abstract = {Chondrites are rocky fragments of asteroids that formed at different times and heliocentric distances in the early solar system. Most chondrite groups contain water-bearing minerals, attesting that both water-ice and dust were accreted on their parent asteroids. Nonetheless, the hydrogen isotopic composition (D/H) of water in the different chondrite groups remains poorly constrained, due to the intimate mixture of hydrated minerals and organic compounds, the other main H-bearing phase in chondrites. Building on our recent works using in situsecondary ion mass spectrometry analyses, we determined the H isotopic composition of water in a large set of chondritic samples (CI, CM, CO, CR, and C-ungrouped carbonaceous chondrites) and report that water in each group shows a distinct and unique D/H signature. Based on a comparison with literature data on bulk chondrites and their water and organics, our data do not support a preponderant role of parent-body processes in controlling the D/H variations among chondrites. Instead, we propose that the water and organic D/H signatures were mostly shaped by interactions between the protoplanetary disk and the molecular cloud that episodically fed the disk over several million years. Because the preservation of D-rich interstellar water and/or organics in chondritic materials is only possible below their respective sublimation temperatures (160 and 350--450 K), the H isotopic signatures of chondritic materials depend on both the timing and location at which their parent body formed.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Barosch_etal2020,

title = {An unusual compound object in Yamato 793408 (H3.2-an) : The missing link between compound chondrules and macrochondrules ?},

author = {J. Barosch and D. C. Hezel and Y. Marrocchi and A. Gurenko and C. Lenting},

doi = {10.1111/maps.13496},

year  = {2020},

date = {2020-01-01},

journal = {Meteoritics \& Planetary Science},

volume = {55},

pages = {1458--1470},

abstract = {We found a large ( 2 mm) compound object in the primitive Yamato 793408 (H3.2‐an) chondrite. It consists mostly of microcrystalline material, similar to chondrule mesostasis, that hosts an intact barred olivine (BO) chondrule. The object contains euhedral pyroxene and large individual olivine grains. Some olivine cores are indicative of refractory forsterites with very low Fe‐ and high Ca, Al‐concentrations, although no 16O enrichment. The entire object is most likely a new and unique type, as no similar compound object has been described so far. We propose that it represents an intermediate stage between compound chondrules and macrochondrules, and formed from the collision between chondrules at low velocities (below 1 m s−1) at high temperatures (around 1550 textdegreeC). The macrochondrule also trapped and preserved a smaller BO chondrule. This object appears to be the first direct evidence for a genetic link between compound chondrules and macrochondrules. In accordance with previous suggestions and studies, compound chondrules and macrochondrules likely formed by the same mechanism of chondrule collisions, and each represents different formation conditions, such as ambient temperature and collision speed.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Barosch_etal2020_2,

title = {Sectioning effects of porphyritic chondrules : Implications for the PP/POP/PO classification and correcting modal abundances of mineralogically zoned chondrules},

author = {J. Barosch and D. C. Hezel and L. Sawatzki and L. Halbauer and Y. Marrocchi},

doi = {10.1111/maps.13476},

year  = {2020},

date = {2020-01-01},

journal = {Meteoritics \& Planetary Science},

volume = {55},

number = {5},

pages = {993--999},

abstract = {Mineralogically zoned chondrules are a common chondrule type in chondrites. They consist of olivine cores, surrounded by low-Ca pyroxene rims. By serial sectioning porphyritic chondrules from carbonaceous, ordinary, and enstatite chondrites, we demonstrate that the 2-D textural appearances of these chondrules largely depend on where they are cut. The same chondrule may appear as a porphyritic pyroxene (PP) chondrule when sectioned through the low-Ca pyroxene rim, and as a porphyritic olivine-pyroxene (POP) or porphyritic olivine (PO) chondrule when sectioned close or through its equator. Chondrules previously classi�textordfeminineed into PP/POP/PO chondrules might therefore not represent different types, but various sections through mineralogically zoned chondrules. Classifying chondrule textures into PP, POP, and PO has therefore no unequivocal genetic meaning, it is merely descriptive. Sectioning effects further introduce a systematic bias when determining mineralogically zoned chondrule fractions from 2-D sections. We determined correction factors to estimate 3-D mineralogically zoned chondrule fractions when these have been determined in 2-D sections : 1.24 for carbonaceous chondrites, 1.29 for ordinary chondrites, and 1.62 for enstatite chondrites. Using these factors then shows that mineralogically zoned chondrules are the dominant chondrule type in chondrites with estimated 3-D fractions of 92% in CC, 52% in OC, and 46% in EC.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Boulliung_etal2020,

title = {Oxygen fugacity and melt composition controls on nitrogen solubility in silicate melts},

author = {J. Boulliung and E. F\"{u}ri and C. Dalou and L. Tissandier and L. Zimmermann and Y. Marrocchi},

doi = {10.1016/j.gca.2020.06.020},

year  = {2020},

date = {2020-01-01},

journal = {Geochimica et Cosmochimica Acta},

volume = {284},

pages = {120--133},

abstract = {Knowledge of N solubility in silicate melts is key for understanding the origin of terrestrial N and the distribution andexchanges of N between the atmosphere, the silicate magma ocean, and the core forming metal. To place constraints onthe incorporation mechanism(s) of N in silicate melts, we investigated the effect of the oxygen fugacity (fO2) and melt com-position on the N solubility through N equilibration experiments at atmospheric pressure and high temperature (1425textdegreeC).Oxygen fugacity (expressed in log units relative to the iron-wu ̈stite buffer, IW) was varied from IW --8 to IW +4.1, and meltcompositions covered a wide range of polymerization degrees, defined by the NBO/T ratio (the number of non-bridging oxy-gen atoms per tetrahedrally coordinated cations). The N contents of the quenched run products (silicate glasses) were ana-lyzed byin-situsecondary ion mass spectrometry and bulk CO2laser extraction static mass spectrometry, yielding resultsthat are in excellent agreement even for N concentrations at the (sub-)ppm level. The data obtained here highlight the fun-damental control offO2and the degree of polymerization of the silicate melt on N solubility. Under highly reduced conditions(fO2= IW --8), the N solubility increased with increasing NBO/T from 17.4 textpm 0.4 ppm.atm-1/2in highly polymerized melts(NBO/T = 0) to 6710 textpm 102 ppm.atm-1/2in depolymerized melts (NBO/T˜2.0). In contrast, under less reducing conditions(fO2\> IW --3.4), N solubility is very low (≤2 ppm.atm-1/2), irrespective of the NBO/T value. Our results provide constraintson N solubility in enstatite chondrite melts and in the shallow part of a planetary magma ocean. The nitrogen storage capacityof an enstatite chondrite melt, which may approximate that of planetesimals that accreted and melted early in the inner SolarSystem, varies between ˜60 and ˜6000 ppm at IW --5.1 and IW --8, respectively. In contrast, a mafic to ultra-mafic magmaocean could have incorporated ˜0.3 ppm to ˜35 ppm N under thefO2conditions inferred for the young Earth (i.e., IW --5 toIW). The N storage capacity of a reduced magma ocean (i.e., IW --3.4 to IW) in equilibrium with a N-rich atmosphere is ≤1 ppm, comparable to the N content of the present-day mantle. However under more reducing conditions (i.e., IW --5 toIW --4), the N storage capacity is significantly higher (˜35 ppm) ; in this case, Earth would have lost N to the atmosphereand/or N would have been transported into and stored within its deep interior (i.e., deep mantle, core).},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Delon_etal2020,

title = {Effect of deformation on helium storage and diffusion in polycrystalline forsterite},

author = {R. Delon and S. Demouchy and Y. Marrocchi and M. Ali Bouhifd and J. Gasc and P. Cordier and S. Koizumi and P. G. Burnard},

doi = {10.1016/j.gca.2020.01.018},

year  = {2020},

date = {2020-01-01},

journal = {Geochimica et Cosmochimica Acta},

volume = {273},

pages = {226--243},

abstract = {Although recent studies have investigated He behavior in undeformed mantle minerals, the effect of defects generated by plastic deformation on He storage and transport remains unconstrained. For this purpose, synthetic dense aggregates of fine-grained iron-free forsterite were deformed under 300 MPa confining pressure at 950, 1050, and 1200 textdegreeC using a Paterson press. Three deformed samples and one undeformed sample were then doped with He under static high-pressure (1.00 textpm 0.02 GPa) and high-temperature (1120 textpm 20 textdegreeC) conditions for 24 h in a piston cylinder. Uraninite was used as a source of noble gases. The samples were subsequently analyzed using a cycled step heating protocol coupled with noble gas mass spectrometry to investigate He storage and diffusion in the deformed polycrystalline forsterite aggregates. Results show complex diffusive behaviors that cannot be fitted by a single linear regression. Nevertheless, individual step heating cycles can be fitted by several linear regressions determined by a F-test, suggesting that diffusivities follow Arrhenius law within the given temperature ranges. Our results highlight the complex diffusive behavior of He in deformed forsterite aggregates, which is due to the competition between several diffusion mechanisms related to different He storage sites (Mg vacancies, interstitial sites, dislocations, and grain boundaries). Diffusion parameters (activation energy Ea and pre-exponential factor D0) for He diffusion in grain boundaries were refined from literature data (Ea = 36 textpm 9 kJtextperiodcenteredmol−1 and D0 = 10−10.57 textpm 0.58 m2textperiodcentereds−1), and those of He diffusion in interstitials (Ea = 89 textpm 7 kJtextperiodcenteredmol−1 and D0 = 10−8.95 textpm 1.16 m2textperiodcentereds−1) and Mg vacancies (Ea = 173 textpm 14 kJtextperiodcenteredmol−1 and D0 = 10−5.07 textpm 1.25 m2textperiodcentereds−1) were defined from our results and literature data. Furthermore, we determined Ea = 56 textpm 1 kJtextperiodcenteredmol−1 and D0 = 10−9.97 textpm 0.37 m2textperiodcentereds−1 for He diffusion along dislocations. These results suggest that a maximum He fraction of only 1.2% can be stored along dislocations in mantle minerals, which is negligible compared to 22% in grain boundaries as reported by previous studies. This implies that bulk lattice diffusivities are barely affected by the presence of dislocations, whereas the proportion of He stored in grain boundaries can significantly enhance the bulk diffusivities of mantle rocks. Thus, deformation processes can significantly increase He storage capacity by decreasing grain size (i.e., via dynamic recrystallization), but will not sufficiently increase the dislocation density to induce a change in He storage and mobility within the crystallographic lattice. Furthermore, rapid redistribution of He between the mineral lattice and grain boundaries could enhance the bulk He concentrations of deformed peridotites upon equilibration with nearby undeformed (or less-deformed) peridotites.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Joy_etal2020,

title = {The isotopic composition of volatiles in the unique Bench Crater carbonaceous chondrite impactor found in the Apollo 12 regolith},

author = {K. H. Joy and R. Tart`ese and S. Messenger and M. E. Zolensky and Y. Marrocchi and D. R. Frank and D. A. Kring},

doi = {10.1016/j.epsl.2020.116265},

year  = {2020},

date = {2020-01-01},

journal = {Earth and Planetary Science Letters},

volume = {540},

pages = {116265},

abstract = {Projectiles striking the Moon have modified its crust and delivered volatile elements to its interior and surface. Direct evidence of impactor origins is recorded by the rare occurrence of sub-cm sized meteorite fragments identified in Apollo samples and lunar meteorites. The Bench Crater meteorite is a millimetre-sized carbonaceous chondrite collected in regolith on the rim of Bench impact crater at the Apollo 12 landing site. Transmission electron microscopy has previously shown that Bench Crater contains abundant hydrated silicates, establishing the survivability of hydrated material impacting the lunar surface. To provide further information on the volatile inventory of the Bench Crater meteorite, we report here the isotope compositions of hydrogen, nitrogen, carbon and oxygen. This is the first direct isotopic analysis of meteoritic material delivered to the lunar surface and provides context for volatile and organic element signatures in lunar regolith samples, and the survivability of volatile material delivered to planetary surfaces during impact bombardment. The Bench Crater meteorite is characterised by $delta$D values ranging between −36 textpm 40 and 200 textpm 40texttenthousand, and bulk average C of −13 textpm 30texttenthousand, and N of −40 textpm 36texttenthousand (all uncertainties at the 2$sigma$ confidence level). The oxygen isotope compositions measured in situ in matrix silicates and magnetite in Bench Crater are consistent with those measured in matrix and magnetite in CI and CM chondrite falls. Altogether, these new H, C, N and O isotope data, coupled to mineralogical and geochemical observations, suggest that Bench Crater may have been derived from an asteroidal parent body not represented in the terrestrial meteorite collection. This is a crucial outcome in the current context of sample-return missions to carbonaceous asteroids, and more broadly for investigating the flux of material delivered to the Earth-Moon system through time.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Marrocchi_etal2020,

title = {The Piancaldoli meteorite : A forgotten primitive LL3.10 ordinary chondrite},

author = {Y. Marrocchi and L. Bonal and J. Gattacceca and L. Piani and P. Beck and R. Greenwood and J. Eschrig and A. Basque and P. M. Nuccio and F. F. Martin},

doi = {10.1111/maps.13552},

year  = {2020},

date = {2020-01-01},

journal = {Meteoritics \& Planetary Science},

volume = {55},

number = {8},

pages = {1924--1935},

abstract = {The Piancaldoli ordinary chondrite fell in northern Italy on August 10, 1968. Preliminary studies led to its classification as an LL3.4 unequilibrated ordinary chondrite. However, recent developments in classification procedures have prompted us to re-examine its mineralogical, petrographic, spectroscopic, chemical, and isotopic features in a multitechnique study. Raman spectra and magnetic properties indicate that Piancaldoli experienced minimal thermal metamorphism, consistent with its high bulk hydrogen content and the Cr contents of ferroan olivines in its type II chondrules. In combination with findings of previous studies, our data thus confirm the variability of Cr contents in ferroan olivines in type II chondrules as a proxy of thermal metamorphism. Furthermore, our results reveal that Piancaldoli is less altered than previously reported and should be reclassified as an LL3.10 unequilibrated ordinary chondrite. Our results also imply that the bulk deuterium enrichment, as observed in Piancaldoli (LL3.10), Bishunpur (LL3.15), and Semarkona (LL3.00), is a specific signature of the most primitive unequilibrated ordinary chondrites. Based on our results, we propose that, to date, Piancaldoli is the second leastaltered unequilibrated ordinary chondrite fall after Semarkona. This work reiterates the importance of meteorite collections worldwide as fundamental resources for studying the formation conditions and evolution of our solar system.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Piani_etal2020,

title = {Earthtextquoterights water may have been inherited from material similar to enstatite chondrite meteorites},

author = {L. Piani and Y. Marrocchi and T. Rigaudier and L. G. Vacher and D. Thomassin and B. Marty},

doi = {10.1126/science.aba1948},

year  = {2020},

date = {2020-01-01},

journal = {Science},

volume = {369},

number = {6507},

pages = {1110--1113},

abstract = {The origin of Earthtextquoterights water remains unknown. Enstatite chondrite (EC) meteorites have similar isotopic composition to terrestrial rocks and thus may be representative of the material that formed Earth. ECs are presumed to be devoid of water because they formed in the inner Solar System. Earthtextquoterights water is therefore generally attributed to the late addition of a small fraction of hydrated materials, such as carbonaceous chondrite meteorites, which originated in the outer Solar System where water was more abundant. We show that EC meteorites contain sufficient hydrogen to have delivered to Earth at least three times the mass of water in its oceans. EC hydrogen and nitrogen isotopic compositions match those of Earthtextquoterights mantle, so EC-like asteroids might have contributed these volatile elements to Earthtextquoterights crust and mantle.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Piralla_etal2020,

title = {Primordial water and dust of the Solar System: Insights from in situ oxygen measurements of CI chondrites},

author = {M. Piralla and Y. Marrocchi and M. J. Verdier-Paoletti and L. G. Vacher and J. Villeneuve and L. Piani and D. V. Bekaert and M. Gounelle},

doi = {10.1016/j.gca.2019.10.041},

year  = {2020},

date = {2020-01-01},

journal = {Geochimica et Cosmochimica Acta},

volume = {269},

pages = {451--464},

abstract = {As the chemical compositions of CI chondrites closely resemble that of the Suntextquoterights photosphere, their oxygen isotopic compositions represent a powerful tool to constrain the origin and dynamics of dust and water ice grains in the protoplanetarydisk. However, parent-body alteration processes make straightforward estimation of the primordial isotopic compositions of CI chondritic water and anhydrous minerals difficult. In this contribution, we used in situ SIMS measurements to determinethe oxygen isotope compositions of mechanically isolated olivine and carbonate grains from the CI chondrite Orgueil and carbonates in a polished section of the CI chondrite Ivuna. Most CI olivine grains have Earth-like O isotopic compositions(D17O ≈ 0texttenthousand) plotting at the intersection of the terrestrial fractionation line and the primitive chondrule minerals line. Ca-carbonates from Orgueil and Ivuna define a trend with d17O = (0.50 textpm 0.05) x d18O + (0.9 textpm 1.4) that differs from massindependent variations observed in secondary phases of other carbonaceous chondrites. These data show that CIs are chemically solar but isotopically terrestrial for oxygen isotopes. This supports models suggesting that primordial Solar System dust was 16O-poor (D17O ≈ 0texttenthousand) relative to the 16O-rich nebular gas. Based on results, mass balance calculations reveal that the pristine O isotopic compositions of carbonaceous chondrite matrices differ significantly from the CI composition, except for CR chondrites (calculated D17O values of CM, CO, CV and CR matrices being --3.97 textpm 1.19texttenthousand, --4.33 textpm 1.45texttenthousand, --7.95textpm 1.95texttenthousand, and --0.07 textpm 1.16texttenthousand, respectively). This confirms an open chondrule-matrix system with respect to oxygen isotopes where chondrule compositions reflect complex processes of chondrule precursor recycling and gas-melt interactions. As the Mg-Si-Fe chondrule budget is also partially controlled by gas-melt interactions, the complementary formation of chondrules and matrix from a single solar-like reservoir -if it exists- require that (i) this reservoir must have been in a closed system with the gas or (ii) the gas had a CI composition to satisfy the elemental mass balance.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Rudraswami_etal2020,

title = {The oxygen isotope compositions of large numbers of small cosmic spherules : Implications for their sources and the isotopic composition of the upper atmosphere},

author = {N. G. Rudraswami and M. J. Genge and Y. Marrocchi and J. Villeneuve and S. Taylor},

doi = {10.1029/2020JE006414},

year  = {2020},

date = {2020-01-01},

journal = {Journal of Geophysical Research (Planets)},

volume = {125},

pages = {e2020JE006414},

abstract = {Cosmic spherules are micrometeorites that melt at high altitude as they enter Earthtextquoterights atmosphere, and their oxygen isotope compositions are partially or completely inherited from the upper atmosphere, depending on the amount of heating experienced and the nature of their precursor materials. In this study, the three oxygen isotope compositions of 137 cosmic spherules are determined using 277 in situ analyses by ion probe. Our results indicate a possible correlation between increasing average $delta$18O compositions of silicate -dominated (S-type) spherules along the series scoriaceous \< porphyritic 0texttenthousand) and are largely derived from ordinary chondrite (OC)-like sources related to S (IV)-type asteroids. Glass and CAT spherules have variable �'u17O values indicating they formed by intense entry heating of both CC and OC -like materials. I-type cosmic spherules have a narrow range of $delta$17O ( 20--25texttenthousand) and $delta$18O ( 38--48texttenthousand) values, with �'u17O ( 0texttenthousand) suggesting their oxygen is obtained entirely from the Earthtextquoterights atmosphere, albeit with signicant mass fractionation owing to evaporative heating. Finally, G-type cosmic spherules have unexpected isotopic compositions and demonstrate little mass fractionation from a CC-like source. The results of this study provide a vital assessment of the wider population of extraterrestrial dust arriving on Earth.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Schneider_etal2020,

title = {Early evolution of the solar accretion disk inferred from Cr-Ti-O isotopes in individual chondrules},

author = {J. M. Schneider and C. Burkhardt and Y. Marrocchi and G. A. Brennecka and T. Kleine},

doi = {10.1016/j.epsl.2020.116585},

year  = {2020},

date = {2020-01-01},

journal = {Earth and Planetary Science Letters},

volume = {551},

pages = {116585},

abstract = {Isotopic anomalies in chondrules hold important clues about the dynamics of mixing and transport processes in the solar accretion disk. The meaning of these anomalies is debated and they have been interpreted to indicate either disk-wide transport of chondrules or local heterogeneities of chondrule precursors. However, all previous studies relied on isotopic data for a single element (either Cr, Ti, or O), which does not allow distinguishing between source and precursor signatures as the cause of the chondrulestextquoteright isotope anomalies. To overcome this problem, we obtained the first combined O, Ti, and Cr isotope data for individual chondrules from enstatite, ordinary, and carbonaceous chondrites. We find that chondrules from non-carbonaceous (NC) chondrites have relatively homogeneous �'u17O, ∊50TI, and ∊54Cr, which are similar to the compositions of their host chondrites. By contrast, chondrules from carbonaceous chondrites (CC) have more variable compositions, some of which differ from the host chondrite compositions. Although the compositions of the analyzed CC and NC chondrules may overlap for either ∊50Ti, ∊54Cr, or �'u17O, in multi-isotope space, none of the CC chondrules plot in the compositional field of NC chondrites, and no NC chondrule plots within the field of CC chondrites. As such, our data reveal a fundamental isotopic difference between NC and CC chondrules, which is inconsistent with a disk-wide transport of chondrules across and between the NC and CC reservoirs. Instead, the isotopic variations among CC chondrules reflect local precursor heterogeneities, which most likely result from mixing between NC-like dust and a chemically diverse dust component that was isotopically similar to CAIs and AOAs. The same mixing processes, but on a larger, disk-wide scale, were likely responsible for establishing the distinct isotopic compositions of the NC and CC reservoirs, which represent in inner and outer disk, respectively.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Villeneuve_etal2020,

title = {Silicon isotopic compositions of chondrule silicates in carbonaceous chondrites and the formation of primordial solids in the accretion disk},

author = {J. Villeneuve and Y. Marrocchi and E. Jacquet},

doi = {10.1016/j.epsl.2020.116318},

year  = {2020},

date = {2020-01-01},

journal = {Earth and Planetary Science Letters},

volume = {542},

pages = {116318},

abstract = {We determined the silicon isotopic compositions of silicates (olivine and low-Ca pyroxene) in type I and type II chondrules of the carbonaceous chondrites Allende, Kaba, NWA (Northwest Africa) 5958, and MIL (Miller Range) 07342. Type I chondrule silicates show large, mass-dependent Si isotopic fractionations, with Si values ranging from −7texttenthousand to +2.6texttenthousand, whereas the Si values of type II chondrule silicates are close to zero and vary by less than 2texttenthousand. When present, Mg-rich relict olivine grains in type II chondrules show larger Si variations than their FeO-rich counterparts. In type I chondrules, low-Ca pyroxenes yield systematically lighter Si values than Mg-rich olivines. Our results show that type I chondrules are complex objects whose Si isotopic compositions derived from their precursors and SiO-rich gas-melt interactions. This corroborates that type I chondrules are nebular products that formed under open-system conditions. Our data also suggest that at least some type II chondrules derived from their type I counterparts. Overall, this demonstrates that recycling was common during the evolution of the protoplanetary disk},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Vacher_etal2020,

title = {Hydrogen in chondrites: Influence of parent body alteration and atmospheric contamination on primordial components},

author = {L. Vacher and L. Piani and T. Rigaudier and D. Thomassin and G. Florin and M. Piralla and Y. Marrocchi},

doi = {10.1016/j.gca.2020.05.007},

year  = {2020},

date = {2020-01-01},

urldate = {2020-01-01},

journal = {Geochimica et Cosmochimica Acta},

volume = {281},

pages = {53--66},

abstract = {Hydrogen occurs at the near percent level in the most hydrated chondrites (CI and CM) attesting to the presence of waterin the asteroid-forming regions. Their H abundances and isotopic signatures are powerful proxies for deciphering the distri-bution of H in the protoplanetary disk and the origin of Earthtextquoterights water. Here, we report H contents and isotopic compositionsfor a set of carbonaceous and ordinary chondrites, including previously analyzed and new samples analyzed after the pow-dered samples were degassed under vacuum at 120textdegreeC for 48 hours to remove adsorbed atmospheric water. By comparing ourresults to literature data, we reveal that the H budgets of both H-poor and H-rich carbonaceous chondrites are largely affectedby atmospheric moisture, and that their precise quantification requires a specific pre-degassing procedure to correct for ter-restrial contamination. Our results show that indigenous H contents of CI carbonaceous chondrites usually considered themost hydrated meteorites might be almost a factor of two lower than those previously reported, with uncontaminated D/H ratios differing significantly from that of Earthtextquoterights oceans. Without pre-degassing, the H concentrations of H-poor samples(e.g., CVs chondrites) are also affected by terrestrial contamination. After correction for contamination, it appears that theamount of water in chondrites is not controlled by the matrix modal abundance, suggesting that the different chondritic par-ent bodies accreted variable amounts of water-ice grains. Our results also imply that (i) thermal metamorphism play an impor-tant role in determining the H content of both CV and ordinary chondrites but without affecting drastically their H isotopiccomposition since no clear D enrichment is observed with the increase of petrographic type and (ii) the D enrichment of ordi-nary chondrite organics does not result from the loss of isotopically light H2induced by metal oxidation but is rather linked tothe persistence of a thermally resistant D-rich component},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Delon_etal2019,

title = {Argon storage and diffusion in Earthtextquoterights upper mantle},

author = {R. Delon and S. Demouchy and Y. Marrocchi and M. A. Bouhifd and P. Cordier and A. Addad and Burnard and P.G.},

doi = {10.1016/j.gca.2019.03.007},

year  = {2019},

date = {2019-01-01},

journal = {Geochimica et Cosmochimica Acta},

volume = {253},

pages = {1--18},

abstract = {In this study, fine-grained polycrystalline olivine was doped with argon at static high pressure (0.30 textpm 0.01 GPa) and high temperature (1050 textpm 25 textdegreeC) conditions during 24 h in a Paterson press, and analysed using a step-heating extraction protocol coupled with noble gas mass spectrometry to investigate argon storage and diffusivity in Earthtextquoterights upper mantle. Our results show that a single diffusion mechanism controlled argon diffusion in our samples during the step heating experiments. Effective Ar diffusion in olivine has a low activation energy, implying that argon diffusivity is governed by both grain boundary and lattice diffusion. Mean values of lattice diffusion parameters obtained from our results and by reprocessing literature data are Ea = 166 textpm 44 kJ mol−1 and D0 = 10−7.04 textpm 1.13 m2textperiodcentereds−1, and grain boundary diffusion parameters determined from our data are Ea = 22 textpm 5 kJtextperiodcenteredmol−1 and D0 = 10−12.87 textpm 0.3 m2textperiodcentereds−1. Isotopic diffusivity ratios were constant and close to the values determined by Grahamtextquoterights law in the C-regime (i.e., bulk diffusion dominated by grain boundary diffusion) and A-regime (i.e., bulk diffusion controlled by grain boundary and lattice diffusion in proportion to the segregation of Ar between those sites), but varied in the B-regime (i.e., bulk diffusion controlled by both grain boundary and lattice diffusion in a complex manner), implying a higher isotopic fractionation in the kinetic B-regime. Extrapolation to typical mantle grain sizes implies that around 22% of the argon in the upper mantle can be stored at grain boundaries and that effective diffusion is mostly in the A-regime, suggesting a low isotopic fractionation and diffusivities faster than lattice diffusivities alone. The consideration of grain boundaries as a potential Ar storage site can modify equilibrium during partial melting and significantly enrich a liquid in Ar during fluid percolation. The grain size dependence of Ar storage and diffusivity highlights the underestimated role of grain boundaries in the upper mantle, especially in zones of reduced grain size (via dynamic recrystallization) possibly followed by fluid percolation and/or partial melting, such as in subduction zones or below oceanic ridges.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Mari_etal2019,

title = {Syneruptive incorporation of martian surface sulphur in the nakhlite lava flows revealed by S and Os isotopes and highly siderophile elements: implication for mantle sources in Mars},

author = {N. Mari and A. J. V. Riches and L. J. Hallis and Y. Marrocchi and J. Villeneuve and P. Gleissner and H. Becker and M. R. Leese},

doi = {10.1016/j.gca.2019.05.025},

year  = {2019},

date = {2019-01-01},

journal = {Geochimica et Cosmochimica Acta},

volume = {266},

pages = {416--434},

abstract = {Martian lava flows likely acquired S-rich material from the regolith during their emplacement on the planettextquoterights surface. We investigated five of the twenty known nakhlites (Nakhla, Lafayette, Miller Range (MIL) 090032, Yamato 000593, and Yamato 000749) to determine whether these lavas show evidence of regolith assimilation, and to constrain the potential implications that this process has on chemical tracing of martian mantle source(s). To establish the proportionate influence of atmospheric, hydrothermal, and volcanic processes on nakhlite isotopic systematics we obtained in situ sulphur isotope data (D33S and d34S) for sulphide grains (pyrrhotite and pyrite) in all five nakhlite samples. For Nakhla, Lafayette, and MIL 090032, these data are integrated with highly siderophile element (HSE) abundances and Os-isotope compositions, as well as textural information constrained prior to isotopic analysis. This work thereby provides the first Re-Os isotope systematics for two different nakhlites, and also the first Re-Os isotope data for martian sample for which detailed petrographic information was constrained prior to digestion. We report the largest variation in d34S yet found in martian meteorites (-13.20texttenthousandto +15.16texttenthousand). The relatively positive D33S and d34S values of MIL 090032 (d34S = +10.54 textpm 0.09texttenthousand ; D33S = -0.67 textpm 0.10texttenthousand) indicate this meteorite assimilated sulphur affected by UV-photochemistry. In contrast, the strongly negative values of Lafayette (d34S = -10.76 textpm 0.14texttenthousand ; D33S = -0.09 textpm 0.12texttenthousand) are indicative of hydrothermal processes on Mars. Nakhla, Yamato 000593, and Yamato 000749 sulphides have a narrower range of sulphur isotope compositions (D33S and d34S 0) that is consistent with no assimilation of martian surface materials during lava flow emplacement. Consequently we used this second group of D33S values to approximate the D33S of the nakhlite source, yielding a D33S value of -0.1texttenthousand. Nakhlite HSE patterns result from a sulphide-saturated melt where Ru-Os-Ir alloys/sulphide were likely crystallized during earlier phases of magmatic processing in Mars to result in the fractionated HSE patterns of the nakhlites. Our data, alongside a synthesis of previously published data, suggest assimilation of an enriched component to the primary nakhlite melt, potentially a late-stage crystallization cumulate from the martian magma ocean stage. In the context of this model, and within large uncertainties, our data hint at perturbation and potential decoupling of nakhlite Re-Os isotope systematics from other isotopic systems as a result of small degrees of assimilation of a regolith component with highly radiogenic 187Os/188Os.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Marrocchi_etal2019,

title = {Formation of CV chondrules by recycling of amoeboid olivine aggregate-like precursors},

author = {Y. Marrocchi and R. Euverte and J. Villeneuve and V. Batanova and B. Welsch and L. Ferri`ere and E. Jacquet},

doi = {10.1016/j.gca.2018.12.038},

year  = {2019},

date = {2019-01-01},

journal = {Geochimica et Cosmochimica Acta},

volume = {247},

number = {2},

pages = {121--141},

abstract = {We have studied porphyritic olivine-rich chondrules of the carbonaceous chondrite Kaba (CV3) by combined high-resolution X-ray mapping, quantitative electron microprobe analyses, and oxygen isotopic analyses via secondary ion mass spectrometry. These chondrules contain smaller inner-chondrule olivine grains characterized by low refractory element (Ca, Al, Ti) contents, and larger outer-chondrule olivine crystals that are enriched in refractory elements and show complex Ti and Al oscillatory zonings. Our O isotopic survey revealed that many of the inner-chondrule olivines are 16O-richer than the relatively isotopically uniform outer-chondrule olivines. Inner-chondrule olivine crystals---only a minority of which may be derived from earlier generations of chondrules---are likely mostly inherited from nebular condensates similar to AOAs, as they share similar isotopic and chemical features and are thus interpreted as relict grains. Still, being 16O-poorer than most AOAs, they may have experienced significant exchange with a 16O-poor reservoir prior to chondrule formation (even if to a lesser degree than relicts in CM2 and ungrouped C2 chondrites). Subsequent incomplete melting of the relict grains produced Ca-Al-Ti-rich melts that engulfed the remaining relict olivine grains. The complex Ti and Al zoning patterns in outer chondrule (host) olivines, in particular the systematic dilution near the margin, seem to reflect gas-melt interactions (with e.g. SiO (g), Mg (g)) which also buffered the O isotopic composition of chondrule hosts. Together, these results demonstrate that important episodes of recycling of nebular condensates occurred in the solar protoplanetary disk.https://doi.org/10.1016/j.gca.2018.12.038},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Marrocchi+Piani2019,

title = {The tumultuous childhood of the Solar System},

author = {Y. Marrocchi and L. Piani},

doi = {10.1038/s41550-019-0868-y},

year  = {2019},

date = {2019-01-01},

journal = {Nature Astronomy},

volume = {3},

number = {10},

pages = {889--890},

abstract = {The peculiar carbon isotopic compositions of carbonates in the Tagish Lake meteorite suggest that D-type asteroids accreted in the outer part of the protoplanetary disk --- beyond 10 au --- before being dispersed sunwards to the main asteroid belt.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Marrocchi_etal2019_2,

title = {Rapid condensation of the first Solar System solids},

author = {Y. Marrocchi and J. Villeneuve and E. Jacquet and M. Piralla and M. Chaussidon},

doi = {/10.1073/pnas.1912479116},

year  = {2019},

date = {2019-01-01},

journal = {PNAS},

volume = {116},

number = {47},

pages = {23461--23466},

abstract = {Chondritic meteorites are composed of primitive components formed during the evolution of the Solar protoplanetary disk. The oldest of these components formed by condensation, yet little is known about their formation mechanism because of secondary heating processes that erased their primordial signature. Amoeboid Olivine Aggregates (AOAs) have never been melted and underwent minimal thermal annealing, implying they might have retained the conditions under which they condensed. We performed a multiisotope (O, Si, Mg) characterization of AOAs to constrain the conditions under which they condensed and the information they bear on the structure and evolution of the Solar protoplanetary disk. High-precision silicon isotopic measurements of 7 AOAs from weakly metamorphosed carbonaceous chondrites show large, mass-dependent, light Si isotope enrichments (--9texttenthousand \< $delta$30Si \< --1texttenthousand). Based on physical modeling of condensation within the protoplanetary disk, we attribute these isotopic compositions to the rapid condensation of AOAs over timescales of days to weeks. The same AOAs show slightly positive $delta$25Mg that suggest that Mg isotopic homogenization occurred during thermal annealing without affecting Si isotopes. Such short condensation times for AOAs are inconsistent with disk transport timescales, indicating that AOAs, and likely other high-temperature condensates, formed during brief localized high-temperature events.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Rudraswami_etal2019,

title = {Oxygen isotopic and chemical composition of chromites in micrometeorites: Evidence of ordinary chondrite precursors},

author = {N. G. Rudraswami and Y. Marrocchi and M. Shyam Prasad and D. Fernandes and J. Villeneuve and S. Taylor},

doi = {10.1111/maps.13281},

year  = {2019},

date = {2019-01-01},

journal = {Meteoritics \& Planetary Science},

volume = {54},

number = {6},

pages = {1347--1361},

abstract = {We identified 66 chromite grains from 42 of textasciitilde5000 micrometeorites collected from Indian Ocean deep‐sea sediments and the South Pole water well. To determine the chromite grains precursors and their contribution to the micrometeorite flux, we combined quantitative electron microprobe analyses and oxygen isotopic analyses by high‐resolution secondary ion mass spectrometry. Micrometeorite chromite grains show variable O isotopic compositions with $delta$18O values ranging from −0.8 to 6.0texttenthousand, $delta$17O values from 0.3 to 3.6texttenthousand, and $Delta$17O values from −0.9 to 1.6texttenthousand, most of them being similar to those of chromites from ordinary chondrites. The oxygen isotopic compositions of olivine, considered as a proxy of chromite in chromite‐bearing micrometeorites where chromite is too small to be measured in ion microprobe have $Delta$17O values suggesting a principal relationship to ordinary chondrites with some having carbonaceous chondrite precursors. Furthermore, the chemical compositions of chromites in micrometeorites are close to those reported for ordinary chondrite chromites, but some contribution from carbonaceous chondrites cannot be ruled out. Consequently, carbonaceous chondrites cannot be a major contributor of chromite‐bearing micrometeorites. Based on their oxygen isotopic and elemental compositions, we thus conclude with no ambiguity that chromite‐bearing micrometeorites are largely related to fragments of ordinary chondrites with a small fraction from carbonaceous chondrites, unlike other micrometeorites deriving largely from carbonaceous chondrites.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Vacher_etal2019,

title = {Thermal evolution of hydrated asteroids inferred from oxygen isotopes},

author = {L. G. Vacher and M. Piralla and M. Gounelle and M. Bizzarro and Y. Marrocchi},

doi = {10.3847/2041-8213/ab3bd0},

year  = {2019},

date = {2019-01-01},

journal = {The Astrophysical Journal Letters},

volume = {882},

pages = {L20},

abstract = {Chondrites are fragments of unmelted asteroids that formed due to gravitational instabilities in turbulent regions of the Solar protoplanetary disk. Hydrated chondrites are common among meteorites, indicating that a substantial fraction of the rocky bodies that formed early in the solar system accreted water ice grains that subsequently melted due to heat released by the radioactive decay of 26Al. However, the thermal histories of asteroids are still largely unknown ; increased knowledge would provide fundamental information on their timing of accretion and their physical characteristics. Here we show that hydrated meteorites (CM chondrites) contain previously uncharacterized calcium carbonates with peculiar oxygen isotopic compositions ($Delta$17O��\'{E}��2.5texttenthousand), which artificially produce the massindependent trend previously reported for carbonates. Based on these isotopic data, we propose a new model to quantitatively estimate the precipitation temperatures of secondary phases (carbonates and serpentine). It reveals that chondritic secondary phases recorded a gradual increase in temperature during the extent of aqueous alteration, from −10textdegreeC to a maximum of 250textdegreeC. We also show that the thermal path of C-type asteroids is independent of the initial oxygen isotopic composition of the primordial water ice grains that they accreted. Our estimated temperatures for hydrated asteroids remain lower than those experienced by other carbonaceous chondrites, providing strong constraints for modeling the formation conditions and size distribution of water-rich asteroids, especially in anticipation of the return of samples of water-rich asteroids to Earth by the OSIRIS-REx and Hayabusa2 missions.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Vacher_etal2019_2,

title = {Deciphering the conditions of tochilinite and cronstedtite formation in CM chondrites from low temperature hydrothermal experiments},

author = {L. G. Vacher and L. Truche and F. Faure and L. Tissandier and R. Mosser-Ruck and Y. Marrocchi},

doi = {10.1111/maps.13317},

year  = {2019},

date = {2019-01-01},

journal = {Meteoritics \& Planetary Science},

volume = {54},

pages = {1870--1889},

abstract = {Tochilinite/cronstedtite intergrowths are commonly observed as alteration products in CM chondrite matrices, but the conditions under which they formed are still largely underconstrained due to their scarcity in terrestrial environments. Here, we report low temperature (80 textdegreeC) anoxic hydrothermal experiments using starting assemblages similar to the constituents of the matrices of the most pristine CM chondrite and S-rich and S-free fluids. Cronstedtite crystals formed only in S-free experiments under circumneutral conditions with the highest Fe/Si ratios. Fe-rich tochilinite with chemical and structural characteristics similar to chondritic tochilinite was observed in S-bearing experiments. We observed a positive correlation between the Mg content in the hydroxide layer of synthetic tochilinite and temperature, suggesting that the composition of tochilinite is a proxy for the alteration temperature in CM chondrites. Using this relation, we estimate the mean precipitation temperatures of tochilinite to be 120--160 textdegreeC for CM chondrites. Given the different temperature ranges of tochilinite and cronstedtite in our experiments, we propose that Fe-rich tochilinite crystals resulted from the alteration of metal beads under S-bearing alkaline conditions at T = 120--160 textdegreeC followed by cronstedtite crystals formed by the reaction of matrix amorphous silicates, metal beads, and water at a low temperature (50--120 textdegreeC).},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Verdier-Paoletti_etal2019,

title = {Testing the genetic relationship between fluid alteration and brecciation in CM chondrites},

author = {M. J. Verdier-Paoletti and Y. Marrocchi and L. G. Vacher and J. Gattacceca and A. Gurenko and C. Sonzogni and M. Gounelle},

doi = {10.1111/maps.13306},

year  = {2019},

date = {2019-01-01},

journal = {Meteoritics \& Planetary Science},

volume = {54},

pages = {1692--1709},

abstract = {Boriskino is a poorly studied CM chondrite with numerous millimeter‐ to centimeter‐scale clasts exhibiting sharp boundaries. Clast textures and mineralogies attest to diverse geological histories with various degrees of aqueous alteration. We conducted a petrographic, chemical, and isotopic study on each clast type of the breccia to investigate if there exists a genetic link between brecciation and aqueous alteration, and to determine the controlling parameter of the extent of alteration. Boriskino is dominated by CM2 clasts for which no specific petrographic type could be assigned based on the chemical compositions and modal abundances of constituents. One clast stands out and is identified as a CM1 lithology, owing to its lack of anhydrous silicates and its overall abundance of dolomite‐like carbonates and acicular iron sulfides. We observe that alteration phases near clast boundaries exhibit foliation features, suggesting that brecciation postdated aqueous alteration. We measured the O‐isotopic composition of Ca‐carbonates and dolomite‐like carbonates to determine their precipitation temperatures following the methodology of Verdier‐Paoletti et al. (2017). Both types of carbonates yield similar ranges of precipitation temperatures independent of clast lithology, ranging from −13.9 textpm 22.4 (2$sigma$) to 166.5 textpm 47.3 textdegreeC, precluding that temperature alone accounts for the differences between the CM1 and CM2 lithologies. Instead, we suggest that initial water/rock ratios of 0.75 and 0.61 for the CM1 and CM2 clasts, respectively, might control the extent of aqueous alteration. Based on these estimates, we suggest that Boriskino clasts originated from a single parent body with heterogeneous distribution of water either due to local differences in the material permeability or in the initial content of ice available. These conditions would have produced microenvironments with differing geochemical conditions thus leading to a range of degrees of aqueous alteration.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Villeneuve_etal2019,

title = {High‐precision in situ silicon isotopic analyses by multicollector secondary ion mass spectrometry in olivine and lowcalcium pyroxene},

author = {J. Villeneuve and M. Chaussidon and Y. Marrocchi and Z. Deng and E. B. Watson},

doi = {10.1002/rcm.8508},

year  = {2019},

date = {2019-01-01},

journal = {Rapid Communications in Mass Spectrometry},

volume = {33},

pages = {1589--1597},

abstract = {High‐precision determination of silicon isotopes can be achieved by in situ multi‐collector secondary ion mass spectrometry (MS‐SIMS). The accuracy of the analyses is, however, sensitive to ion yields and instrumental mass fractionations (IMFs) induced by the analytical procedure. These effects vary from one instrument to another, with the analytical settings, and with the composition and nature of the sample. Because ion yields and IMF effects are not predictable and rely on empirical calibrations, high‐accuracy analyses require suitable sets of standards. Methods : Here, we document calibrations of ion yields and matrix effects in a set of 23 olivine standards and 3 low‐Ca pyroxene for silicon isotopic measurements in both polarities using Cameca IMS 1270 E7 and IMS 1280 HR2 ion probes set with the cesium (Cs) or radiofrequency (RF) source. Results : Silicon ion yields show (i) strong variations with the chemical composition, and (ii) an opposite behavior between the secondary positive and negative polarities. The magnitude of IMF along the fayalite‐forsterite (olivine) series shows a complex behavior, increasing overall by ≈7texttenthousand (secondary positive) and ≈15texttenthousand (secondary negative) with increasing olivine Mg#. A drastic change in olivine IMF occurs at Mg#≈70 in both polarities. The magnitude of IMF for low‐Ca pyroxene from Mg#= 70--100 is almost constant in both polarities, i.e. ≈0.1texttenthousand in secondary positive and ≈0.15texttenthousand in secondary negative. The analytical uncertainties on individual analyses were textpm 0.05--0.15texttenthousand (2 S.E.) with both sources, and the external errors for each standard material were ≈ textpm0.05--0.5texttenthousand (2 S.E.) with the Cs source and ≈ textpm0.03--0.15texttenthousand (2 S.E.) with the RF source. Conclusions : The IMF effect of Si isotopes in silicates shows complex behaviors that vary with the chemistry and the settings of the instrument. We developed a suitable set of standards in order to perform high‐accuracy in situ measurements of Si isotopes in olivine and low‐Ca pyroxene characterized by varying chemical compositions by MC‐SIMS.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Bekaert_etal2018,

title = {Primordial heavy noble gases in the pristine Paris carbonaceous chondrite},

author = {D. Bekaert and Y. Marrocchi and A. Meshik and L. Remusat and B. Marty},

doi = {10.1111/maps.13213},

year  = {2018},

date = {2018-01-01},

journal = {Meteoritics \& Planetary Science},

volume = {54},

number = {2},

pages = {395--414},

abstract = {The Paris carbonaceous chondrite represents the most pristine carbonaceous chondrite, providing a unique opportunity to investigate the composition of early solar system materials prior to the onset of significant aqueous alteration. A dual origin (namely from the inner and outer solar system) has been demonstrated for water in the Paris meteorite parent body (Piani et al. 2018). Here, we aim to evaluate the contribution of outer solar system (cometary‐like) water ice to the inner solar system water ice using Xe isotopes. We report Ar, Kr, and high‐precision Xe isotopic measurements within bulk CM 2.9 and CM 2.7 fragments, as well as Ne, Ar, Kr, and Xe isotope compositions of the insoluble organic matter (IOM). Noble gas signatures are similar to chondritic phase Q with no evidence for a cometary‐like Xe component. Small excesses in the heavy Xe isotopes relative to phase Q within bulk samples are attributed to contributions from presolar materials. CM 2.7 fragments have lower Ar/Xe relative to more pristine CM 2.9 fragments, with no systematic difference in Xe contents. We conclude that Kr and Xe were little affected by aqueous alteration, in agreement with (1) minor degrees of alteration and (2) no significant differences in the chemical signature of organic matter in CM 2.7 and CM 2.9 areas (Vinogradoff et al. 2017). Xenon contents in the IOM are larger than previously published data of Xe in chondritic IOM, in line with the Xe component in Paris being pristine and preserved from Xe loss during aqueous alteration/thermal metamorphism},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Bekaert_etal2018_4,

title = {High-temperature ionization-induced synthesis of biologically relevant molecules in the protosolar nebula},

author = {D. V. Bekaert and S. Derenne and L. Tissandier and Y. Marrocchi and S. Charnoz and C. Anquetil and B. Marty},

doi = {10.3847/1538-4357/aabe7a},

year  = {2018},

date = {2018-01-01},

journal = {Astrophysical Journal},

volume = {859},

number = {142},

abstract = {Biologically relevant molecules (hereafter biomolecules) have been commonly observed in extraterrestrial samples, but the mechanisms accounting for their synthesis in space are not well understood. While electron-driven production of organic solids from gas mixtures reminiscent of the photosphere of the protosolar nebula (PSN; i.e., dominated by CO--N2--H2) successfully reproduced key specific features of the chondritic insoluble organic matter (e.g., elementary and isotopic signatures of chondritic noble gases), the molecular diversity of organic materials has never been investigated. Here, we report that a large range of biomolecules detected in meteorites and comets can be synthesized under conditions typical of the irradiated gas phase of the PSN at temperatures=800 K. Our results suggest that organic materials---including biomolecules---produced within the photosphere would have been widely dispersed in the protoplanetary disk through turbulent diffusion, providing a mechanism for the distribution of organic meteoritic precursors prior to any thermal/photoprocessing and subsequent modification bysecondary parent body processes. Using a numerical model of dust transport in a turbulent disk, we propose that organic materials produced in the photosphere of the disk would likely be associated with small dust particles, which are coupled to the motion of gas within the disk and therefore preferentially lofted into the upper layers of the disk where organosynthesis occurs.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Delon_etal2018,

title = {Helium incorporation and diffusion in polycrystalline olivine},

author = {R. Delon and S. Demouchy and Y. Marrocchi and M. A. Bouhifd and F. Barou and P. Cordier and A. Addad and P. G. Burnard},

doi = {10.1016/j.chemgeo.2018.01.013},

year  = {2018},

date = {2018-01-01},

journal = {Chemical Geology},

volume = {488},

pages = {105--124},

abstract = {Helium is a key tracer of mantle geochemical and isotopic heterogeneities and can constrain our understanding of mantle geodynamics. Nevertheless, the mechanisms of helium storage and transport in mantle minerals remain poorly understood. Polycrystalline olivine was doped with helium at high temperature (1050 textpm 25 textdegreeC) and high pressure (0.30 textpm 0.01 GPa), followed by step heating extraction experiments to investigate helium storage and diffusion in Earthtextquoterights upper mantle. We also tested the effect of heterogeneous initial concentrations on the extracted diffusivities, and demonstrate the robustness of diffusion parameters obtained in this study. Our results show that two diffusion processes are acting in polycrystalline olivine : (i) a high temperature process with high activation energy ( Ea) where diffusion is only controlled by lattice diffusion, and (ii) a lower temperature process with lower Ea where diffusion is controlled by both grain boundary and lattice diffusion. These two diffusion processes are separated by a transition temperature that depends on the depletion of helium hosted in grain boundaries, i.e., the amount of helium stored at grain boundaries and the temperature and duration of the step heating sequence. Our results confirm that grain boundaries can represent a significant storage site for He. Moreover, we report two different populations of diffusion parameters in the lattice diffusion field, which are interpreted as diffusion in interstitials (Ea= 95 textpm 15 kJtextperiodcenteredmol−1 and log(D0)=−8.26 textpm 2.13) and Mg vacancies (Ea= 168 textpm 19 kJtextperiodcenteredmol−1 and log(D0)=− 3.59 textpm 2.12). Similar diffusion parameters populations are observed in literature data after reprocessing the diffusivities. Furthermore, we determine grain boundary diffusion parameters : Ea = 57 textpm 14 kJtextperiodcenteredmol−1 and log(D0)=−9.20 textpm 0.99. Applying these results to the upper mantle reveals that an important amount of He can be stored at grain boundaries for typical mantle grain size (22% for a grain size of 1 mm) and that most helium can be stored at grain boundaries for relatively small grain sizes (≤290$mu$m and ≤10$mu$m for segregation factors of 1/10−5 and 1/0.0025, respectively). As a consequence, bulk diffusivities can be significantly higher than lattice diffusivities. Although our study cannot be applied directly to the lower mantle, the similar storage sites and diffusion mechanisms are expected in lower mantle silicates if high pressure does not inhibit diffusion},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Marrocchi_etal2018,

title = {Origin and abundance of water in carbonaceous asteroids},

author = {Y. Marrocchi and D. V. Bekaert and L. Piani},

doi = {10.1016/j.epsl.2017.10.060},

year  = {2018},

date = {2018-01-01},

journal = {Earth and Planetary Science Letters},

volume = {482},

pages = {23--32},

abstract = {The origin and abundance of water accreted by carbonaceous asteroids remains underconstrained, but would provide important information on the dynamic of the protoplanetary disk. Here we report the in situoxygen isotopic compositions of aqueously formed fayalite grains in the Kaba and Mokoia CV chondrites. CV chondrite bulk, matrix and fayalite O-isotopic compositions define the mass-independent continuous trend ($delta$17O =0.84 textpm0.03 texttimes$delta$18O −4.25 textpm0.1), which shows that the main process controlling the O-isotopic composition of the CV chondrite parent body is related to isotopic exchange between 16O-rich anhydrous silicates and 17O-and 18O-rich fluid. Similar isotopic behaviors observed in CM, CR and CO chondrites demonstrate the ubiquitous nature of O-isotopic exchange as the main physical process in establishing the O-isotopic features of carbonaceous chondrites, regardless of their alteration degree. Based on these results, we developed a new approach to estimate the abundance of water accreted by carbonaceous chondrites (quantified by the water/rock ratio) with CM (0.3--0.4) �WCR (0.1--0.4) �WCV (0.1--0.2) \>CO (0.01--0.10). The low water/rock ratios and the O-isotopic characteristics of secondary minerals in carbonaceous chondrites indicate they (i) formed in the main asteroid belt and (ii)accreted a locally derived (inner Solar System) water formed near the snowline by condensation from the gas phase. Such results imply low influx of D-and 17O-and 18O-rich water ice grains from the outer part of the Solar System. The latter is likely due to the presence of a Jupiter-induced gap in the protoplanetary disk that limited the inward drift of outer Solar System material at the exception of particles with size lower than 150$mu$m such as presolar grains. Among carbonaceous chondrites, CV chondrites show O-isotopic features suggesting potential contribution of 17--18O-rich water that may be related to their older accretion relative to other hydrated carbonaceous chondrites.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Marrocchi_etal2018_2,

title = {Oxygen isotopic diversity of chondrule precursors and the nebular origin of chondrules},

author = {Y. Marrocchi and J. Villeneuve and V. Batanova and L. Piani and E. Jacquet},

doi = {10.1016/j.epsl.2018.05.042},

year  = {2018},

date = {2018-01-01},

journal = {Earth and Planetary Science Letters},

volume = {496},

pages = {132--141},

abstract = {FeO-poor (type I) porphyritic chondrules formed by incomplete melting of solid dust precursors viaa yet-elusive mechanism. Two settings are generally considered for their formation: (i) a nebular setting where primordial solids were melted, e.g. by shock waves propagating through the gas and (ii) a collisional planetary setting. Here we report a method combining high-current electron microprobe X-ray mapping and quantitative measurements to determine the chemical characteristics of relict olivine grains inherited from chondrule precursors. We find that these olivine crystals are Ca--Al--Ti-poor relative to host olivine crystals. Their variable $Delta$17O, even in individual chondrule, is inconsistent with derivation from planetary interiors as previously argued from 120◦triple junctions also exhibited by the chondrules studied herein. This indicates that chondrule precursors correspond to solid nebular condensates formed under changing physical conditions.We propose that porphyritic chondrules formed during gas-assisted melting of nebular condensates comprising relict olivine grains with varying $Delta$17O values and Ca--Al--Ti-rich minerals such as those observed within amoeboid olivine aggregates. Incomplete melting of chondrule precursors produced Ca--Al--Ti-rich melts (CAT-melts), allowing subsequent crystallization of Ca--Al--Ti-rich host olivine crystalsviaepitaxial growth on relict olivine grains. Incoming MgO and SiO from the gas phase induced (i)the dilution of CAT-melts, as attested by the positive Al--Ti correlation observed in chondrule olivine crystals, and (ii) buffering of the O-isotope compositions of chondrules, as recorded by the constant $Delta$17O values of host olivine grains. The O-isotopic compositions of host olivine grains are chondrule-specific, suggesting that chondrules formed in an array of environments of the protoplanetary disk with different $Delta$17O values, possibly due to variable solid/gas mixing ratios.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Piani+Marrocchi2018,

title = {Hydrogen isotopic composition of water in CV-type carbonaceous chondrites},

author = {L. Piani and Y. Marrocchi},

doi = {10.1016/j.epsl.2018.09.031},

year  = {2018},

date = {2018-01-01},

journal = {Earth and Planetary Science Letters},

volume = {504},

pages = {64--71},

abstract = {Among the different groups of carbonaceous chondrites, variable concentrations of hydrous minerals and organic matter are observed that might be related to the time and/or place of formation of their asteroidal parent bodies. However, the precise distribution of these volatile-bearing components between chondrite groups and their chemical and isotopic compositions remain fairly unknown. In this study, we used a novel secondary ion mass spectrometry analytical protocol to determine the hydrogen isotopic composition of water-bearing minerals in CV-type carbonaceous chondrites. This protocol allows for the first time the D/H ratio of CV chondrite hydrous minerals to be determined without hindrance by hydrogen contributions from adjacent organic material. We found that water in the altered CV chondrites Kaba, Bali, and Grosnaja has an average D/H ratio of D/HCV-water=[144+8−21] texttimes10−6(or $delta$DCV-water=−77+54−131textdegree/textdegreetextdegree, 2$sigma$), significantly higher than water in most CM-type carbonaceous chondrites (D/HCM-water=[101 textpm6] texttimes10−6or $delta$DCM-water=−350 textpm40textdegree/textdegreetextdegree, 2$sigma$). We show that because organic matter in CV chondrites is depleted in deuterium compared to that in CM chondrites, such differences could result from isotopic exchange between water and organics. Another possibility is that the CM and CV parent bodies sampled different reservoirs of water ice and organics characterized by variable isotopic compositions due to their different time and/or place of accretion.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Pignatelli_etal2018,

title = {Cronstedtite polytypes in the Paris meteorite},

author = {I. Pignatelli and E. Mugnaioli and Y. Marrocchi},

doi = {10.1127/ejm/2018/0030-2713},

year  = {2018},

date = {2018-01-01},

journal = {European Journal of Mineralogy},

volume = {30},

pages = {349--354},

abstract = {We present the first detailed crystallo-chemical and crystallographic description of cronstedtite with extraterrestrial origin. The analysed crystals occur as pseudomorphs after anhydrous silicates in the Paris meteorite, which is the least altered carbonaceous chondrite currently known. Three-dimensional electron diffraction data have been collected by electron diffraction tomography andused to identify the cronstedtite polytypes, because of their small size. All identified polytypes are MDO (Maximum degree of order), and the most abundant one is 1T. Many other crystals also belong to the Baileytextquoterights group (or OD subfamily) C, but their stacking disorder hampers the polytype identification. Only in one crystal could the 3T and 2M1 polytypes be recognised. TEM-EDX data indicate that the chemical composition of the crystals is similar, regardless of their polytypic sequence.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Vacher_etal2018,

title = {Collisional and alteration history of the CM parent body},

author = {L. Vacher and Y. Marrocchi and J. Villeneuve and M. J. Verdier-Paoletti and M. Gounelle},

doi = {10.1016/j.gca.2018.08.006},

year  = {2018},

date = {2018-01-01},

journal = {Geochimica et Cosmochimica Acta},

volume = {239},

pages = {213--234},

abstract = {Boriskino is a little studied CM2 chondrite composed of millimeter-sized clasts of different lithologies and degrees of alteration. Boriskino thus offers a good opportunity to better understand the preaccretionary alteration history and collisional evolution that took place on the CM parent body. The least altered lithology displays 16O-poor Type 1a calcite and aragonite grains (d18O textasciitilde 30--37texttenthousand, d17O textasciitilde 15--18texttenthousand and D17Otextasciitilde-2 to 0texttenthousand, SMOW) that precipitated early, before the establishment of the petrofabric, from a fluid whose isotopic composition was established by isotopic exchange between a 16O-poor water and 16O-rich anhydrous silicates. In contrast, the more altered lithologies exhibit 16O-rich Type 2a and veins of calcite (d18O textasciitilde 17-- 23texttenthousand, d17O textasciitilde 6--9texttenthousand and D17Otextasciitilde-4 to -1texttenthousand, SMOW) that precipitated after establishment of the deformation, from transported16O-rich fluid in preexisting fractures. From our petrographic and X-ray tomographic results, we propose that the more altered lithologies of Boriskino were subjected to high intensity impact(s) (10--30 GPa) that produced a petrofabric, fractures and chondrule flattening. Taking all our results together, we propose a scenario for the deformation and alteration history of Boriskino, in which the petrographic and isotopic differences between the lithologies are explained by their separate locations into a single CM parent body. Based on the d13C-d18O values of the Boriskino Type 2a calcite (d13C textasciitilde 30--71texttenthousand,PDB), we propose an alternative d13C-d18O model where the precipitation of Type 2a calcite can occurred in an open system environment with the escape of 13C-depleted CH4 produced from the reduction of C-bearing species by H2 released during serpentinization or kamacite corrosion. Assuming a mean precipitation temperature of 110 textdegreeC, the observed d13C variability in T2a calcite can be reproduced by the escape of textasciitilde15--50% of dissolved carbon into CH4 by Rayleigh distillation.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Gattacceca_etal2017,

title = {Young asteroid mixing revealed in ordinary chondrites: The case of NWA 5764, a polymict LL breccia with L clasts},

author = {J. Gattacceca and A. Krzesinska and Y. Marrocchi and M. M. M. Meier and M. Bourot-Denise and R. Lenssen},

year  = {2017},

date = {2017-01-01},

journal = {Meteoritics \& Planetary Science},

volume = {52},

number = {11},

pages = {2289--2304},

abstract = {Polymict chondritic breccias---rocks composed of fragments originating fromdifferent chondritic parent bodies---are of particular interest because they give insights into the mixing of asteroids in the main asteroid belt (occurrence, encounter velocity, transfer time). We describe Northwest Africa (NWA) 5764, a brecciated LL6 chondrite that contains a \>16 cm3 L4 clast. The L clast was incorporated in the breccia through a nondestructive, low-velocity impact. Identical cosmic-ray exposure ages of the L clast and the LL host (36.6 +- 5.8 Myr), suggest a short transfer time of the L meteoroid to the LL parent bodyof 0.1 +- 8.1 Myr, if that meteoroid was no larger than a few meters. NWA 5764 (together with St. Mesmin, Dimmitt, and Glanerbrug) shows that effective mixing is possible between ordinary chondrite parent bodies. In NWA 5764 this mixing occurred after the peak of thermal metamorphism on the LL parent body, i.e., at least several tens of Myr after the formation of the solar system. The U,Th-He ages of the L clast and LL host, identical at about 2.9 Ga, might date the final assembly of the breccia, indicating relatively young mixing in the main asteroid belt as previously evidenced in St. Mesmin.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Jacquet+Marrocchi2017,

title = {Chondrule heritage and thermal histories from trace element and oxygen isotope analyses of chondrules and amoeboid olivine aggregates},

author = {E. Jacquet and Y. Marrocchi},

doi = {doi: 10.1111/maps.12985},

year  = {2017},

date = {2017-01-01},

journal = {Meteoritics \& Planetary Science},

pages = {1--23},

abstract = {We report combined oxygen isotope and mineral-scale trace element analyses of amoeboid olivine aggregates (AOA) and chondrules in ungrouped carbonaceous chondrite, Northwest Africa 5958. The trace element geochemistry of olivine in AOA, for the first time measured by LA-ICP-MS, is consistent with a condensation origin, although the shallow slope of its rare earth element (REE) pattern is yet to be physically explained. Ferromagnesian silicates in type I chondrules resemble those in other carbonaceous chondrites both geochemically and isotopically, and we find a correlation between 16O enrichment and many incompatible elements in olivine. The variation in incompatible element concentrations may relate to varying amounts of olivine crystallization during a subisothermal stage of chondrule-forming events, the duration of which may be anticorrelated with the local solid/gas ratio if this was the determinant of oxygen isotopic ratios as proposed recently. While aqueous alteration has depleted many chondrule mesostases in REE, some chondrules show recognizable subdued group II-like patterns supporting the idea that the immediate precursors of chondrules were nebular condensates.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Kuga_etal2017,

title = {Processes of noble gas elemental and isotopic fractionations in plasma-produced organic solids: Cosmochemical implications},

author = {M. Kuga and G. Cernogora and Y. Marrocchi and L. Tissandier and B. Marty},

doi = {10.1016/j.gca.2017.08.031},

year  = {2017},

date = {2017-01-01},

journal = {Geochimica et Cosmochimica Acta},

volume = {217},

pages = {219--230},

abstract = {The main carrier of primordial heavy noble gases in chondrites is thought to be an organic phase, known as phase Q, whose precise characterization has resisted decades of investigation. The Q noble gas component shows elemental and isotopicfractionation relative to the Solar, in favor of heavy elements and isotopes. These noble gas characteristics were experimentally simulated using a plasma device called the textquotelefttextquoteleftNebulotrontextquoterighttextquoteright. In this study, we synthesized thirteen solid organic samples by electron-dissociation of CO, in which a noble gas mixture was added. The analysis of their heavy noble gas (Ar, Kr and Xe) contents and isotopic compositions reveals enrichment in the heavy noble gas isotopes and elements relative to the light ones. The isotope fractionation is mass-dependent and is consistent with a mn-type law, where n 
 1. Based on a plasma model, wepropose that the ambipolar diffusion of ions in the ionized CO gas medium is at the origin of the noble gas isotopic fractionation. In addition, the elemental fractionation of experimental and chondritic samples can be accounted for by the Saha law of plasma equilibrium, which does not depend on the respective noble gas masses but rather on their ionization potentials. Our results suggest that the Q noble gases were trapped into growing organic particles starting from solar gases that were fractionated in an ionized medium by ambipolar diffusion and Saha processes. This would imply that both the formation of chondritic organic matter and the trapping of noble gases took place simultaneously in the ionized areas of the protoplanetary disk.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Pignatelli_etal2017_2,

title = {Mineralogical, crystallographic and redox features of the earliest stages of fluid alteration in CM chondrites},

author = {I. Pignatelli and Y. Marrocchi and E. Mugnaioli and F. Bourdelle and M. Gounelle},

doi = {10.1016/j.gca.2017.04.017},

year  = {2017},

date = {2017-01-01},

journal = {Geochimica et Cosmochimica Acta},

volume = {209},

pages = {106--122},

abstract = {The CM chondrites represent the largest group of hydrated meteorites and span a wide range of conditions, from less altered (i.e., CM2) down to heavily altered (i.e., CM1). The Paris chondrite is considered the least altered CM and thusenables the earliest stages of aqueous alteration processes to be deciphered. Here, we report results from a nanoscale study of tochilinite/cronstedtite intergrowths (TCIs) in Paris---TCIs being the emblematic secondary mineral assemblages of CM chondrites, formed from the alteration of Fe-Ni metal beads (type-I TCIs) and anhydrous silicates (type-II TCIs). We combined high-resolution transmission electron microscopy, scanning transmission X-ray microscopy and electron diffraction tomography to characterize the crystal structure, crystal chemistry and redox state of TCIs. The data obtained are useful to reconstruct the alteration conditions of Paris and to compare them with those of other meteorites. Our results show that tochilinite in Paris is characterized by a high hydroxide layer content (n = 2.1--2.2) regardless of the silicate precursors. When examined alongside other CMs, it appears that the hydroxide layer and iron contents oftochilinites correlate with the degree of alteration experienced by the chondrites. The Fe3+/RFe ratios of TCIs are high: 8--15% in tochilinite, 33--60% in cronstedtite and 70--80% in hydroxides. These observations suggest that alteration of CM chondrites took place under oxidizing conditions that could have been induced by significant H2 release during serpentinization. Similar results were recently reported in CR chondrites (Le Guillou et al., 2015), suggesting that the process (es) controlling the redox state of the secondary mineral assemblages were quite similar in the CM and CR parent bodies despite the different alteration conditions. According to our mineralogical and crystallographic survey, the formation of TCIs in Paris occurred at temperatures lower than 100 
C, under neutral, slightly alkaline conditions that favored the formation of both tochilinite and cronstedtite. During the course of alteration, the reduction in sulfur activity and/or the decrease of temperature prevented tochilinite crystallization and favoured the formation of cronstedtite and iron hydroxides. We suggest that iron hydroxides probably formed as ferrihydrite and then progressively converted to goethite between 50textdegree and 80 textdegreeC, a temperaturerange that is also favorable for cronstedtite formation. The presence of cronstedtite plays a key role in the reconstruction},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Vacher_etal2017,

title = {Petrographic and C \& O isotopic characteristics of the earliest stages of aqueous alteration of CM chondrites},

author = {L. Vacher and Y. Marrocchi and J. Villeneuve and M. J. Verdier-Paoletti and M. Gounelle},

doi = {10.1016/j.gca.2017.06.049},

year  = {2017},

date = {2017-01-01},

journal = {Geochimica et Cosmochimica Acta},

volume = {213},

pages = {271--290},

abstract = {CM chondrites form the largest group of hydrated meteorites and span a wide range of alteration states, with the Paris meteorite being the least altered CM described to date. Ca-Carbonates are powerful proxies for the alteration conditionsof CMs because they are direct snapshots of the chemical and isotopic compositions of the parent fluids. Here, we report a petrographic and a C isotope and O isotope survey of Ca-carbonates in Paris in order to better characterize the earlieststages of aqueous alteration. Petrographic observations show that Paris contains two distinct populations of Cacarbonates: Type 1a Ca-carbonates, which are surrounded by rims of tochilinite/cronstedtite intergrowths (TCIs), and newType 0 Ca-carbonates, which do not exhibit the TCI rims. The TCI rims of Type 1a Ca-carbonates commonly outline euhedral crystal faces, demonstrating that these Ca-carbonates were (i) partially or totally pseudomorphosed by TCI and (ii) precipitated at the earliest stages of aqueous alteration, before Type 0 Ca-carbonates. Isotopic measurements show that Paristextquoteright Ca-carbonates have d13C values that range from 19 to 80texttenthousand (PDB), d18O values that range from 29 to 41%, and d17O values that range from 13 to 24texttenthousand (SMOW). According to the d13C--d18O values of Paristextquoteright Ca-carbonates, we developed a new alteration model that involves (i) the equilibration of a primordial 17,18O-rich water (PW) with 16O-rich anhydrous silicates and (ii) varying contribution of 12C- and 13C-rich soluble organic matter (SOMs). It also suggests that many parameters control the C and O isotopic composition of Ca-carbonates, the principles being the degree of isotopic equilibration between the PW and the anhydrous silicates, the respective contribution of 12C and 13C-rich SOMs as well as the thermal evolution of CM parentbodies. Consequently, we suggest that CM Ca-carbonates could record both positive and negative d13C--d18O relationships, but a systematic correspondence is probably absent in CM chondrites due to the large number of factors involved in generatingthe isotopic characteristics of Ca-carbonates. From recent reports of the C-isotopic compositions of SOM in CM chondrites, we propose that water-soluble organic compounds were the most probable source of 13C enrichment in the majority of CM carbonates.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Vacher_etal2017_2,

title = {Erratum: textquotelefttextquoteleftInward Radial Mixing of Interstellar Water Ices in the Solar Protoplanetary Disktextquoterighttextquoteright (2016, ApJL, 827, L1)},

author = {L. G. Vacher and Y. Marrocchi and M. J. Verdier-Paoletti and J. Villeneuve and M. Gounelle},

year  = {2017},

date = {2017-01-01},

journal = {The Astrophysical Journal Letters},

volume = {836},

number = {1},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Verdier-Paoletti_etal2017,

title = {Oxygen isotope constraints on the alteration temperatures of CM chondrites},

author = {M. J. Verdier-Paoletti and Y. Marrocchi and G. Avice and M. Roskosz and A. Gurenko and M. Gounelle},

doi = {10.1016/j.epsl.2016.10.055},

year  = {2017},

date = {2017-01-01},

journal = {Earth and Planetary Science Letters},

volume = {458},

pages = {273--281},

abstract = {We report a systematic oxygen isotopic survey of Ca-carbonates in nine different CM chondrites characterized by different degrees of alteration, from the least altered known to date (Paris, 2.7--2.8) to the most altered (ALH 88045, CM1). Our data define a continuous trend that crosses the Terrestrial Fractionation Line (TFL), with a general relationship that is indistinguishable within errors from the trend defined by both matrix phyllosilicates and bulk O-isotopic compositions of CM chondrites. This bulk-matrix-carbonate (BMC) trend does not correspond to a mass-dependent fractionation (i.e., slope 0.52) as it would be expected during fluid circulation along a temperature gradient. It is instead a direct proxy of the degree of O-isotopic equilibration between 17,18O-rich fluids and 16O-rich anhydrous minerals. Our O-isotopic survey revealed that, for a given CM, no carbonate is in O-isotopic equilibrium with its respective surrounding matrix. This precludes direct calculation of the temperature of carbonate precipitation. However, the O-isotopic compositions of alteration water in different CMs (inferred from isotopic mass-balance calculation and direct measurements) define another trend (CMW for CM Water), parallel to BMC but with a different intercept. The distance between the BMC and CMW trends is directly related to the temperature of CM alteration and corresponds to average carbonates and serpentine formation temperatures of 110◦C and 75◦C, respectively. However, carbonate O-isotopic variations around the BMC trend indicate that they formed at various temperatures ranging between 50and 300◦C, with 50% of the carbonates studied here showing precipitation temperature higher than 100◦C. The average �'u17O and the average carbonate precipitation temperature per chondrite are correlated, revealing that all CMs underwent similar maximum temperature peaks, but that altered CMs experienced protracted carbonate precipitation event(s) at lower temperatures than the least altered CMs. Our data suggest that the �'u17O value of Ca-carbonates could be a reliable proxy of the degree of alteration experienced by CM chondrites.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Marrocchi_etal2016,

title = {Early scattering of the solar protoplanetary disk recorded in meteoritic chondrules},

author = {Y. Marrocchi and M. Chaussidon and L. Piani and G. Libourel},

doi = {10.1126/sciadv.1601001},

year  = {2016},

date = {2016-01-01},

journal = {Science Advances},

abstract = {Meteoritic chondrules are submillimeter spherules representing the major constituent of nondifferentiated planetesimals formed in the solar protoplanetary disk. The link between the dynamics of the disk and the origin of chondrulesremains enigmatic. Collisions between planetesimals formed at different heliocentric distances were frequent early in the evolution of the disk. We show that the presence, in some chondrules, of previously unrecognized magnetites of magmatic origin implies the formation of these chondrules under impact-generated oxidizing conditions. The three oxygen isotopes systematic of magmatic magnetites and silicates can only be explained by invoking an impact between silicate-rich and ice-rich planetesimals. This suggests that these peculiar chondrules areby-products of the early mixing in the disk of populations of planetesimals from the inner and outer solar system.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Piani_etal2016,

title = {Magmatic sulfides in the porphyritic chondrules of EH enstatite chondrites},

author = {L. Piani and Y. Marrocchi and G. Libourel and L. Tissandier},

doi = {10.1016/j.gca.2016.09.010},

year  = {2016},

date = {2016-01-01},

journal = {Geochimica et Cosmochimica Acta},

volume = {195},

pages = {84--99},

abstract = {The nature and distribution of sulfides within 17 porphyritic chondrules of the Sahara 97096 EH3 enstatite chondrite have been studied by backscattered electron microscopy and electron microprobe in order to investigate the role of gas--melt interactions in the chondrule sulfide formation. Troilite (FeS) is systematically present and is the most abundant sulfide within the EH3 chondrite chondrules. It is found either poikilitically enclosed in low-Ca pyroxenes or scattered within the glassy mesostasis. Oldhamite (CaS) and niningerite [(Mg,Fe,Mn)S] are present in ≈60% of the chondrules studied. While oldhamite is preferentially present in the mesostasis, niningerite associated with silica is generally observed in contact with troilite and low-Ca pyroxene. The Sahara 97096 chondrulemesostases contain high abundances of alkali and volatile elements (average Na2O = 8.7 wt.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Pignatelli_etal2016_2,

title = {Multiple precursors of secondary mineralogical assemblages in CM chondrites},

author = {I. Pignatelli and Y. Marrocchi and L. Vacher and R. Delon and M. Gounelle},

doi = {10.1111/maps.12625},

year  = {2016},

date = {2016-01-01},

journal = {Meteoritics \& Planetary Science},

volume = {51},

number = {4},

pages = {785--805},

abstract = {We report a petrographic and mineralogical survey of tochilinite/cronstedtiteintergrowths (TCIs) in Paris, a new CM chondrite considered to be the least altered CM identified to date. Our results indicate that type-I TCIs consist of compact tochilinite/cronstedtite rims surrounding Fe-Ni metal beads, thus confirming kamacite as the precursor of type-I TCIs. In contrast, type-II TCIs are characterized by complex compositional zoning composed of three different Fe-bearing secondary minerals: from the outside inwards, tochilinite, cronstedtite, and amakinite. Type-II TCIs present well-developed faces that allowa detailed morphological analysis to be performed in order to identify the precursors. The results demonstrate that type-II TCIs formed by pseudomorphism of the anhydrous silicates, olivine, and pyroxene. Hence, there is no apparent genetic relationship between type-I and type-II TCIs. In addition, the complex chemical zoning observed within type-II TCIs suggests that the alteration conditions evolved dramatically over time. At least three stages of alteration can be proposed, characterized by alteration fluids with varying compositions (1) Fe- and S-rich fluids; (2) S-poor and Fe- and Si-rich fluids; and (3) S- andSi-poor, Fe-rich fluids. The presence of unaltered silicates in close association with euhedral type-II TCIs suggests the existence of microenvironments during the first alteration stages of CM chondrites. In addition, the absence of Mg-bearing secondary minerals in Paris TCIs suggests that the Mg content increases during the course of alteration.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Protin_etal2016,

title = {Irreversible adsorption of atmospheric helium on olivine: A lobster pot analogy},

author = {M. Protin and P. H. Blard and Y. Marrocchi and F. Mathon},

doi = {10.1016/j.gca.2016.01.032},

year  = {2016},

date = {2016-01-01},

journal = {Geochimica et Cosmochimica Acta},

volume = {179},

pages = {76--88},

abstract = {This study reports new experimental results that demonstrate that large amounts of atmospheric helium may be adsorbed onto the surfaces of olivine grains. This behavior is surface-area-related in that this contamination preferentially affects grains that are smaller than 125 lm in size. One of the most striking results of our study is that in vacuo heating at 900 textdegreeC for 15 min is not sufficient to completely remove the atmospheric contamination. This suggests that the adsorption of helium may involve high-energy trapping of helium through irreversible anomalous adsorption. This trapping process of helium can thus be compared to a textquotelefttextquoteleftlobster pottextquoterighttextquoteright adsorption: atmospheric helium easily gets in, but hardly gets out. While this type of behavior has previously been reported for heavy noble gases (Ar, Kr, Xe), this is the first time that it has been observed for helium. Adsorption of helium has, until now, generally been considered to be negligible on silicate surfaces. Our findings have significant implications for helium and noble gas analysis of natural silicate samples, such as for cosmic-ray exposure dating or noble gas characterization of extraterrestrial material. Analytical procedures in future studies should be adapted in order to avoid this contamination. The results of this study also allow us to propose an alternative explanation for previously described matrix loss of cosmogenic 3He.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Vacher_etal2016,

title = {Inward radial mixing of interstellar water ices in the solar protoplanetary disk},

author = {L. Vacher and Y. Marrocchi and M. J. Verdier-Paoletti and J. Villeneuve and M. Gounelle},

doi = {10.3847/2041-8205/827/1/L1},

year  = {2016},

date = {2016-01-01},

journal = {The Astrophysical Journal Letters},

volume = {826},

pages = {1--6},

abstract = {The very wide diversity of asteroid compositions in the main belt suggests significant material transport in the solar protoplanetary disk and hints at the presence of interstellar ices in hydrated bodies. However, only a few quantitative estimations of the contribution of interstellar ice in the inner solar system have been reported, leading to considerable uncertainty about the extent of radial inward mixing in the solar protoplanetary disk 4.56 Ga ago. We show that the pristine CM chondrite Paris contains primary Ca-carbonates whose O-isotopic compositions require an 8%--35% contribution from interstellar water. The presence of interstellar water in Paris is confirmed by its bulk D/H isotopic composition that shows significant D enrichment (D/H = (167textpm0.2)texttimes10−6) relative to the mean D/H of CM chondrites ((145textpm3)texttimes10−6) and the putative D/H of local CM water((82textpm1.5)texttimes10−6). These results imply that (i) efficient radial mixing of interstellar ices occurred from the outer zone of the solar protoplanetary disk inward and that (ii) chondrites accreted water ice grains from increasingheliocentric distances in the solar protoplanetary disk},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Burnard_etal2015,

title = {The role of grain boundaries in the storage and transport of noble gases in the mantle},

author = {P. G. Burnard and S. Demouchy and R. Delon and N. O. Arnaud and Y. Marrocchi and P. Cordier and A. Addad},

doi = {10.1016/j.epsl.2015.08.024},

year  = {2015},

date = {2015-01-01},

journal = {Earth and Planetary Science Letters},

volume = {430},

pages = {260--270},

abstract = {Mantle noble gases record important and ancient isotopic heterogeneities, which fundamentally influence our understanding of mantle geodynamics, yet these heterogeneities are difficult to fully interpret with-out understanding the basic mechanisms of noble gas storage and transport in mantle minerals. A series of annealing experiments that mimic mantle conditions (i.e. sub-solidus with natural, polycrystalline, tex-turally equilibrated olivines at low noble gas partial pressures) show that intergranular interfaces (grain boundaries) are major hosts for noble gases in the mantle, and that interfaces can dramatically fraction-ate noble gases from their radio-parents (U +Th and K). Therefore, noble gas isotopic heterogeneities in the mantle could result from grain size variations. Fine-grained lithologies (mylonites and ultramylonites, for example) with more grain boundaries will have lower U/3He ratios (compared to a coarse grained equivalent), which, over time, will preserve higher 3He/4He ratios. As predicted by theory of points de-fect diffusivity, these results show that noble gas diffusion along interfaces is different from those in the grain lattice itself at low temperatures. However, for grain size relevant of the Earthtextquoterights mantle, the re-sulting effective correlated activation energies (Ea)and pre-exponential factors (Do/a2)produce similar diffusivities at mantle temperatures for interface-and lattice-hosted helium. Therefore, grain boundaries do not significantly affect helium transport at mantle conditions and length scales.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Marrocchi_etal2015,

title = {Multiple carriers of Q noble gases in primitive meteorites},

author = {Y. Marrocchi and G. Avice and N. Estrade},

doi = {10.1002/ 2015GL063198},

year  = {2015},

date = {2015-01-01},

journal = {Geophysical Research Letters},

volume = {42},

pages = {2093--2099},

abstract = {The main carrier of primordial heavy noble gases in chondrites is thought to be an organic phase, known as phase Q, whose precise characterization has resisted decades of investigation. Indirect techniques have revealed that phase Q might be composed of two subphases, one of them associated with sulfide. Here we provide experimental evidence that noble gases trapped within meteoritic sulfidespresent chemically and thermally driven behavior patterns that are similar to Q gases. We therefore suggest that phase Q is likely composed of two subcomponents: carbonaceous phases and sulfides. In situ decay of iodine at concentration levels consistent with those reported for meteoritic sulfides can reproduce the 129Xe excess observed for Q gases relative to fractionated solar wind. We suggest that the Q-bearing sulfides formed at high temperature and could have recorded the conditions that prevailed in the chondrule-forming region(s).},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Marrocchi+Chaussidon2015,

title = {A systematic for oxygen isotopic variation in meteoritic chondrules},

author = {Y. Marrocchi and M. Chaussidon},

doi = {10.1016/j.epsl.2015.08.032},

year  = {2015},

date = {2015-01-01},

journal = {Earth and Planetary Science Letters},

volume = {430},

pages = {308--315},

abstract = {Primitive meteorites are characteristically formed from an aggregation of sub-millimeter silicate spherules called chondrules. Chondrules are known to present large three-isotope oxygen variations, much larger than shown by any planetary body. We show here that the systematic of these oxygen isotopic variations results from open-system gas--meltexchanges during the formation of chondrules, a conclusion that has not been fully assessed up to now. We have considered Mg-rich porphyritic chondrules and have modeled the oxygen isotopic effects that would result from high-temperature interactions in the disk between precursor silicate dust and a gas enriched in SiO during the partial melting and evaporation of this dust. This formation process predicts: (i) a range of oxygen isotopic composition for bulk chondrules in agreement with that observed in Mg-rich porphyritic chondrules, and (ii) variable oxygen isotopic disequilibrium between chondrule pyroxene and olivine, which can be used as a proxy of the dust enrichment in the chondrule-forming region(s). Such enrichments are expected during shock waves that produce transient evaporation of dust concentrated in the mid-plane of the accretion disk or in the impact plumes generated during collisions between planetesimals. According to the present model, gas--melt interactions under high PSiO(gas)left strong imprints on the major petrographic, chemical and isotopic characteristics of Mg-rich porphyritic chondrules.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Pignatelli_etal2015_2,

title = {Comment on textquotelefttextquoteleftHydrothermal preparation of analogous matrix minerals of CM carbonaceous chondrites from metal alloy particlestextquoterighttextquoteright by Y. Peng and Y.Jing [Earth Planet. Sci. Lett. 408 (2014) 252--262]},

author = {I. Pignatelli and L. Vacher and Y. Marrocchi},

doi = {10.1016/j.epsl.2015.07.048},

year  = {2015},

date = {2015-01-01},

journal = {Earth and Planetary Science Letters},

volume = {428},

pages = {304--306},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Hewins_etal2014,

title = {The Paris meteorite, the least altered CM chondrite so far},

author = {R. H. Hewins and M. Bourot-Denise and B. Zanda and H. Leroux and J. A. Barrat and M. Humayun and C. G\"{o}pel and R. C. Greenwood and I. A. Franchi and S. Pont and J. P. Lorand and C. Courn`ede and J. Gattacceca and P. Rochette and M. Kuga and Y. Marrocchi and B. Marty},

doi = {10.1016/j.gca.2013.09.014},

year  = {2014},

date = {2014-01-01},

journal = {Geochimica et Cosmochimica Acta},

volume = {124},

pages = {190--222},

abstract = {The Paris chondrite provides an excellent opportunity to study CM chondrules and refractory inclusions in a more pristinestate than currently possible from other CMs, and to investigate the earliest stages of aqueous alteration captured within asingle CM bulk composition. It was found in the effects of a former colonial mining engineer and may have been an observedfall. The texture, mineralogy, petrography, magnetic properties and chemical and isotopic compositions are consistent withclassification as a CM2 chondrite. There are 45 vol.% high-temperature components mainly Type I chondrules (with olivinemostly Fa0--2, mean Fa0.9) with granular textures because of low mesostasis abundances. Type II chondrules contain olivineFa7 to Fa76. These are dominantly of Type IIA, but there are IIAB and IIB chondrules, II(A)B chondrules with minor highlyferroan olivine, and IIA(C) with augite as the only pyroxene. The refractory inclusions in Paris are amoeboid olivine aggregates(AOAs) and fine-grained spinel-rich Ca--Al-rich inclusions (CAIs). The CAI phases formed in the sequence hibonite,perovskite, grossite, spinel, gehlenite, anorthite, diopside/fassaite and forsterite. The most refractory phases are embeddedin spinel, which also occurs as massive nodules. Refractory metal nuggets are found in many CAI and refractory platinumgroup element abundances (PGE) decrease following the observed condensation sequences of their host phases. Mn--Cr isotopemeasurements of mineral separates from Paris define a regression line with a slope of 53Mn/55Mn = (5.76 textpm 0.76)  106.If we interpret Cr isotopic systematics as dating Paris components, particularly the chondrules, the age is 4566.44 textpm 0.66 Myr,which is close to the age of CAI and puts new constraints on the early evolution of the solar system. Eleven individual Parissamples define an O isotope mixing line that passes through CM2 and CO3 falls and indicates that Paris is a very fresh sample,with variation explained by local differences in the extent of alteration. The anhydrous precursor to the CM2s was CO3-like,but the two groups differed in that the CMs accreted a higher proportion of water. Paris has little matrix (47%, plus 8% fine grained rims) and is less altered than other CM chondrites. Chondrule silicates (except mesostasis), CAI phases, submicronforsterite and amorphous silicate in the matrix are all well preserved in the freshest domains, and there is abundant metalpreserved (metal alteration stage 1 of Palmer and Lauretta (2011)). Metal and sulfide compositions and textures correspondto the least heated or equilibrated CM chondrites, Category A of Kimura et al. (2011). The composition of tochilinite--cronstedtiteintergrowths gives a PCP index of 2.9. Cronstedtite is more abundant in the more altered zones whereas in normalhighly altered CM chondrites, with petrologic subtype 2.6--2.0 based on the S/SiO2 and PFeO/SiO2 ratios in PCP or tochilinite--cronstedtite intergrowths (Rubin et al., 2007), cronstedtite is destroyed by alteration. The matrix in fresh zones has CIchondritic volatile element abundances, but interactions between matrix and chondrules occurred during alteration, modifyingthe volatile element abundances in the altered zones. Paris has higher trapped Ne contents, more primitive organic compounds,and more primitive organic material than other CMs. There are gradational contacts between domains of differentdegree of alteration, on the scale of 1 cm, but also highly altered clasts, suggesting mainly a water-limited style of alteration,with no significant metamorphic reheating.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Kuga_etal2014,

title = {Nitrogen isotopic fractionation during abiotic synthesis of organic solid particles},

author = {M. Kuga and N. Carrasco and B. Marty and Y. Marrocchi and S. Bernard and T. Rigaudier and B. Fleury and L. Tissandier},

doi = {10.1016/j.epsl.2014.02.037},

year  = {2014},

date = {2014-01-01},

journal = {Earth and Planetary Science Letters},

volume = {393},

pages = {2--13},

abstract = {The formation of organic compounds is generally assumed to result from abiotic processes in the Solar System, with the exception of biogenic organics on Earth. Nitrogen-bearing organics are of particular interest, notably for prebiotic perspectives but also for over all comprehension of organic formation in the young Solar System and in planetary atmospheres. We have investigated abiotic synthesis of organics upon plasma discharge, with special attention to N isotope fractionation. Organic aerosols were synthesized from N2--CH4 and N2--CO gaseous mixtures using low-pressure plasma discharge experiments, aimed at simulating chemistry occurring in Titantextquoteright atmosphere and in the protosolar nebula, respectively. The nitrogen content, the N speciation and the N isotopic composition were analyzed in the resulting organic aerosols. Nitrogen is efficiently incorporated in to the synthesized solids, independently of the oxidation degree, of the N2 content of the starting gas mixture, and of the nitrogen speciation in the aerosols.The aerosols are depleted in 15N by15--25- relative to the initial N2 gas, whatever the experimental setup is. Such an isotopic fractionation is attributed to mass-dependent kinetic effect(s). Nitrogen isotope fractionation upon electric discharge cannot account for the large N isotope variations observed among Solar System objects and reservoirs. Extreme N isotope signatures in the Solar System are more likely the result of self-shielding during N2 photodissociation, exotic effect during photodissociation of N2 and/or low temperature ion-molecule isotope exchange. Kinetic N isotope fractionation may play a significant role in the Titantextquoterights atmosphere. On the Titantextquoterights night side, 15N depletion resulting from electron driven reactions may counterbalance photo-induced 15N enrichments occurring on the daytextquoterights side.We also suggest that the low $delta$15N values of Archaean organic matter (Beaumont and Robert,1999) are partly the result of abiotic synthesis of organics that occurred at that time, and that the subsequent development of the biosphere resulted in shifts of $delta$15N towards higher values.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Marrocchi_etal2014,

title = {The Paris CM chondrite: Secondary minerals and asteroidal processing},

author = {Y. Marrocchi and M. Gounelle and I. Blanchard and F. Caste and A. T. Kearsley},

doi = {10.1111/maps.12329},

year  = {2014},

date = {2014-01-01},

journal = {Meteoritics \& Planetary Science},

volume = {49},

number = {7},

pages = {1232--1249},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Marrocchi+Libourel2013,

title = {Sulfur and sulfides in chondrules},

author = {Y. Marrocchi and G. Libourel},

doi = {10.1016/j.gca.2013.05.020},

year  = {2013},

date = {2013-01-01},

journal = {Geochimica et Cosmochimica Acta},

volume = {119},

pages = {117--136},

abstract = {The nature and distribution of sulfides within type I PO, POP and PP chondrules of the carbonaceous chondrite Vigarano (CV3) have been studied by secondary electron microscopy and electron microprobe. They occur predominantly as spheroidalblebs composed entirely of low-Ni iron sulfide (troilite, FeS) or troilite + magnetite but in less abundance in association with metallic Fe--Ni beads in opaque assemblages. Troilites are mainly located within the low-Ca pyroxene outer zone and their amounts increase with the abundance of low-Ca pyroxene within chondrules, suggesting co-crystallization of troilite and low-Ca pyroxene during high-temperature events. We show that sulfur concentration and sulfide occurrence in chondrules obey high temperature sulfur solubility and saturation laws. Depending on the fS2 and fO2 of the surrounding gas and on the melt composition, mainly the FeO content, sulfur dissolved in chondrule melts may eventually reach a concentration limit, the sulfur content at sulfide saturation (SCSS), at which an immiscible iron sulfide liquid separates from the silicate melt. Theoccurrence of both a silicate melt and an immiscible iron sulfide liquid is further supported by the non-wetting behavior of sulfides on silicate phases in chondrules due to the high interfacial tension between their precursor iron-sulfide liquid droplets and the surrounding silicate melt during the high temperature chondrule-forming event.The evolution of chondrule melts from PO to PP towards more silicic compositions, very likely due to high PSiO(g) of the surrounding nebular gas, induces saturation of FeS at much lower S content in PP than in PO chondrules, leading to the cocrystallization of iron sulfides and low-Ca pyroxenes. Conditions of co-saturation of low-Ca pyroxene and FeS are only achieved in non canonical environments characterized by high partial pressures of sulfur and SiO and redox conditions more oxidizing than IW-3. Fe and S mass balance calculations also suggest the occurrence of an external source of iron, very likely gaseous, during chondrule formation. We therefore propose that enrichments in sulfur (and other volatile and moderately volatile elements) from PO to PP type I bulk chondrule compositions towards chondritic values result from progressive reactionbetween partially depleted olivine-bearing precursors and a volatile-rich gas phase.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Marrocchi+Marty2013,

title = {Experimental determination of the xenon isotopic fractionation during adsorption},

author = {Y. Marrocchi and B. Marty},

doi = {10.1002/grl.50845},

year  = {2013},

date = {2013-01-01},

journal = {Geophysical Research Letters},

volume = {40},

pages = {4165--4170},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Piani_etal2012,

title = {Structure, composition, and location of organic matter in the enstatite chondrite Sahara 97096 (EH3)},

author = {L. Piani and F. Robert and O. Beyssac and L. Binet and M. Bourot-Denise and S. Derenne and C. Le Guillou and Y. Marrocchi and S. Mostefaoui and J. N. Rouzaud and A. Thomen},

doi = {10.1111/j.1945-5100.2011.01306.x},

year  = {2012},

date = {2012-01-01},

journal = {Meteoritics \& Planetary Science},

volume = {47},

number = {1},

pages = {8--29},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Colin_etal2011,

title = {Plume-ridge interaction along the Galapagos Spreading Center: discerning between gas loss and source effects using neon isotopic compositions and 4He-40Ar*-CO2 relative abundances},

author = {A. Colin and P. G. Burnard and D. W. Graham and Y. Marrocchi},

doi = {10.1016/j.gca.2010.11.018},

year  = {2011},

date = {2011-01-01},

journal = {Geochimica et Cosmochimica Acta},

volume = {75},

number = {4},

pages = {1145--1160},

abstract = {To document the plume--ridge interaction at the Galapagos Spreading Center (GSC), we present neon 3-isotope analyses performed on vesicles-trapped volatiles of MORB glasses dredged along the ridge axis between 86 W and 98 W. 4He--40Ar*-- CO2 relative abundances were also measured in order to study gas loss in this context and discern between source and degassing effects. Neon isotopic compositions are in the MORB range with 21Ne/22Ne ratios extrapolated to the 20Ne/22Ne mantleratio of 12.5 varying between 0.053 and 0.072. Unradiogenic plume-like compositions were not measured. The 4He--40Ar*-- CO2 relative abundances are highly variable along the ridge, for example 4He/40Ar* ratio varies between 3 and 433, but these variations can be fully explained by a simple model of Rayleigh distillation, with a single volatile source composition for the entire GSC. Magma fractional crystallisation, which increases in the plume influenced zone, seems to be the main motor for degassing. As other geochemical and geophysical studies indicate a significant plume influence on the GSC, these results suggest the plume component feeding the ridge is either degassed or else different from the plume core.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Marrocchi_etal2011,

title = {Adsorption of xenon ions onto defects in organic surfaces: Implications for the origin and the nature of organics in primitive meteorites},

author = {Y. Marrocchi and B. Marty and P. Reinhardt and F. Robert},

doi = {10.1016/j.gca.2011.07.048},

year  = {2011},

date = {2011-01-01},

journal = {Geochimica et Cosmochimica Acta},

volume = {75},

pages = {6255--6266},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Westall_etal2011,

title = {Implications of in situ calcification for photosynthesis in a textasciitilde3.3 Ga-old microbial biofilm from the Barberton greenstone belt, South Africa},

author = {F. Westall and B. Cavalazzi and L. Lemelle and Y. Marrocchi and J. N. Rouzaud and A. Simionovici and M. Salom\'{e} and S. Mostefaoui and C. Andreazza and F. Foucher and J. Toporski and A. Jauss and V. Thiel and G. Southam and L. MacLean and S. Wirick and A. Hofmann and A. Meibom and F. Robert and C. D\'{e}farge},

doi = {doi:10.1016/j.epsl.2011.08.029},

year  = {2011},

date = {2011-01-01},

journal = {Earth and Planetary Science Letters},

volume = {310},

pages = {468--479},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Marrocchi_etal2009,

title = {Neon isotopic measurements using high-resolution, multicollector noble gas mass spectrometer: HELIX-MC},

author = {Y. Marrocchi and P. Burnard and D. Hamilton and A. Colin and M. Pujol and L. Zimmermann and B. Marty},

doi = {10.1029/2008GC002339},

year  = {2009},

date = {2009-01-01},

journal = {Geochemistry, Geophysics, Geosystems G3},

volume = {10},

number = {4},

pages = {1--8},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Marrocchi_etal2005,

title = {Interlayer trapping of noble gases in insoluble organic matter of primitive meteorites},

author = {Y. Marrocchi and S. Derenne and B. Marty and F. Robert},

doi = {10.1016/j.epsl.2005.04.010},

year  = {2005},

date = {2005-01-01},

journal = {Earth and Planetary Science Letters},

volume = {236},

number = {3-4},

pages = {569--578},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Marrocchi_etal2005_2,

title = {Low-pressure adsorption of Ar, Kr, and Xe on carbonaceous materials (kerogen and carbon blacks), ferrihydrite, and montmorillonite: Implications for the trapping of noble gases onto meteoritic matter},

author = {Y. Marrocchi and A. Razafitianmaharavo and L. J. Michot and B. Marty},

doi = {10.1016/j.gca.2004.09.016},

year  = {2005},

date = {2005-01-01},

journal = {Geochimica et Cosmochimica Acta},

volume = {69},

number = {9},

pages = {2419--2430},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Marrocchi+Toplis2005,

title = {Experimental determination of argon solubility in silicate melts: An assessment of the effects of liquid composition and temperature},

author = {Y. Marrocchi and M. J. Toplis},

doi = {10.1016/j.gca.2005.08.010},

year  = {2005},

date = {2005-01-01},

journal = {Geochimica Et Cosmochimica Acta},

volume = {69},

number = {24},

pages = {5765--5776},

keywords = {},

pubstate = {published},

tppubtype = {article}

}