Nicolas Schnuriger

@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{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{Schnuriger_etal2020,

title = {Long-lived volcanism expressed through mare infilling, domes and IMPs in the Arago region of the Moon},

author = {N. Schnuriger and J. Flahaut and M. Martinot and S. D. Chevrel},

doi = {10.1016/j.pss.2020.104901},

year  = {2020},

date = {2020-01-01},

journal = {Planetary and Space Science},

volume = {185},

pages = {104901},

abstract = {Mare Tranquillitatis corresponds to the deposit of successive Early to Late Imbrian basaltic units filling the Tranquillitatis basin on the Moon. The present study focuses on the western half of the mare, in the vicinity of the Arago crater (6.16textdegreeN, 21.42textdegreeE). High resolution datasets from recent remote sensing missions were used to reconstruct the geologic history of the area, which includes a variety of geological features such as: 8 extrusive domes, numerous wrinkle ridges, a sinuous rille and 37 Irregular Mare Patches (IMPs). We performed crater counting to date the domes emplacement and estimated the domes lava rheologic properties (plastic viscosities, lava effusion rates, and durations of effusion) using their geometric characteristics. As a result we classify the Arago domes into three groups: E1-type domes (Arago 1 and 8), H1-type domes (Arago 4 to 7), and B-type domes (Arago 2 and 3) respectively emplaced $null$textasciitilde $null$3.7 $null$Ga, textasciitilde3.4 $null$Ga, and textasciitilde2.8 $null$Ga ago. IMPs are observed in the younger mare unit and on the top of the Arago 6 dome; they likely correspond to a late stage of waning mare volcanism in the area. Both IMPs and domes have a composition similar to the surrounding mare in the VNIR spectral domain, consistent with mafic materials. The exceptionally long-lived volcanism and its diversity recorded in the Arago region may be related to both a Th-rich anomaly reported nearby and to the large-scale magma center responsible for the Lamont positive Bouguer anomaly. In addition, volcanic features of the Arago region are superimposed on a Ti-rich mare unit visited by the Apollo 11 crew 175 $null$km to the south at Tranquility Base. The geological and historical richness of this region makes it a compelling site for future science and/or In Situ Resources Utilization (ISRU) driven missions to the Moon.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}