2023
|
Marrocchi, Y., Rigaudier, T., Piralla, M., Piani, L. Hydrogen isotopic evidence for nebular pre-hydration and the limited role of parent-body processes in CM chondrites (Article de journal) Dans: Earth and Planetary Science Letters, vol. 611, no. 2, p. 118151, 2023. @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}
}
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. |
Piani, L., Nagashima, K., Kawasaki, N., Sakamoto, N., Bajo, K. I., Abe, Y., J.,, Aléon, Hydrogen isotopic composition of hydrous minerals in Asteroid Ryugu (Article de journal) Dans: The Astrophysical Journal, vol. 946, no. L43, 2023. @article{Piani_etal2023,
title = {Hydrogen isotopic composition of hydrous minerals in Asteroid Ryugu},
author = {L. Piani and K. Nagashima and N. Kawasaki and N. Sakamoto and K. I. Bajo and Y. Abe and J. and Al\'{e}on},
doi = {10.3847/2041-8213/acc393},
year = {2023},
date = {2023-01-01},
journal = {The Astrophysical Journal},
volume = {946},
number = {L43},
abstract = {Rock fragments of the Cb-type asteroid Ryugu returned to Earth by the JAXA Hayabusa2 mission share mineralogical, chemical, and isotopic properties with the Ivuna-type (CI) carbonaceous chondrites. Similar to CI chondrites, these fragments underwent extensive aqueous alteration and consist predominantly of hydrous minerals likely formed in the presence of liquid water on the Ryugu parent asteroid. Here we present an in situ analytical survey performed by secondary ion mass spectrometry from which we have estimated the D/H ratio of Ryugu’s hydrous minerals, D/HRyugu, to be [165 textpm 19] texttimes 10\^{a}6, which corresponds to $delta$DRyugu = +59 textpm 121texttenthousand (2$sigma$). The hydrous mineral D/HRyugu’s values for the two sampling sites on Ryugu are similar; they are also similar to the estimated D/H ratio of hydrous minerals in the CI chondrites Orgueil and Alais. This result reinforces a linkbetween Ryugu and CI chondrites and an inference that Ryugu’s samples, which avoided terrestrial contamination, are our best proxy to estimate the composition of water at the origin of hydrous minerals in CI-like material. Based on this data and recent literature studies, the contribution of CI chondrites to the hydrogen of Earth’s surficial reservoirs is evaluated to be \^{a}`u3%. We conclude that the water responsible for the alteration of Ryugu’s rocks was derived from water ice precursors inherited from the interstellar medium; the ice partially reequilibrated its hydrogen with the nebular H2 before being accreted on the Ryugu’s parent asteroid.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Rock fragments of the Cb-type asteroid Ryugu returned to Earth by the JAXA Hayabusa2 mission share mineralogical, chemical, and isotopic properties with the Ivuna-type (CI) carbonaceous chondrites. Similar to CI chondrites, these fragments underwent extensive aqueous alteration and consist predominantly of hydrous minerals likely formed in the presence of liquid water on the Ryugu parent asteroid. Here we present an in situ analytical survey performed by secondary ion mass spectrometry from which we have estimated the D/H ratio of Ryugu’s hydrous minerals, D/HRyugu, to be [165 textpm 19] texttimes 10â6, which corresponds to $delta$DRyugu = +59 textpm 121texttenthousand (2$sigma$). The hydrous mineral D/HRyugu’s values for the two sampling sites on Ryugu are similar; they are also similar to the estimated D/H ratio of hydrous minerals in the CI chondrites Orgueil and Alais. This result reinforces a linkbetween Ryugu and CI chondrites and an inference that Ryugu’s samples, which avoided terrestrial contamination, are our best proxy to estimate the composition of water at the origin of hydrous minerals in CI-like material. Based on this data and recent literature studies, the contribution of CI chondrites to the hydrogen of Earth’s surficial reservoirs is evaluated to be â`u3%. We conclude that the water responsible for the alteration of Ryugu’s rocks was derived from water ice precursors inherited from the interstellar medium; the ice partially reequilibrated its hydrogen with the nebular H2 before being accreted on the Ryugu’s parent asteroid. |
2022
|
Izidoro, A., Piani, L. Origin of water in the terrestrial planets: Insights from meteorite data and planet formation models (Article de journal) Dans: Elements, vol. 18, no. 3, p. 181–186, 2022. @article{Izidoro+Piani2022,
title = {Origin of water in the terrestrial planets: Insights from meteorite data and planet formation models},
author = {A. Izidoro and L. Piani},
doi = {10.2138/gselements.18.3.181},
year = {2022},
date = {2022-01-01},
journal = {Elements},
volume = {18},
number = {3},
pages = {181--186},
abstract = {Water condensed as ice beyond the water snowline, the location in the Sun’s natal gaseous disk where temperatures were below 170 K. As the disk evolved and cooled, the snowline moved inwards. A low temperature in the terrestrial planet-forming region is unlikely to be the origin of water on the planets, and the distinct isotopic compositions of planetary objects formed in the inner and outer disks suggest limited early mixing of inner and outer Solar System materials. Water in our terrestrial planets has rather been derived from H-bearing materials indigenous to the inner disk and delivered by water-rich planetesimals formed beyond the snowline and scattered inwards during the growth, migration, and dynamical evolution of the giant planets.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Water condensed as ice beyond the water snowline, the location in the Sun’s natal gaseous disk where temperatures were below 170 K. As the disk evolved and cooled, the snowline moved inwards. A low temperature in the terrestrial planet-forming region is unlikely to be the origin of water on the planets, and the distinct isotopic compositions of planetary objects formed in the inner and outer disks suggest limited early mixing of inner and outer Solar System materials. Water in our terrestrial planets has rather been derived from H-bearing materials indigenous to the inner disk and delivered by water-rich planetesimals formed beyond the snowline and scattered inwards during the growth, migration, and dynamical evolution of the giant planets. |
Almayrac, M. G., Bekaert, D. V., Broadley, M. W., Byrne, D. J., Piani, L., Marty, B. The EXCITING experiment exploring the behavior of nitrogen and noble gases in interstellar ice analogs (Article de journal) Dans: The Planetary Science Journal, vol. 3, p. 252, 2022. @article{Almayrac_etal2022,
title = {The EXCITING experiment exploring the behavior of nitrogen and noble gases in interstellar ice analogs},
author = {M. G. Almayrac and D. V. Bekaert and M. W. Broadley and D. J. Byrne and L. Piani and B. Marty},
doi = {10.3847/PSJ/ac98b0},
year = {2022},
date = {2022-01-01},
journal = {The Planetary Science Journal},
volume = {3},
pages = {252},
abstract = {Comets represent some of the most pristine bodies in our solar system and can provide a unique insight into the chemical makeup of the early solar system. Due to their icy volatile-rich nature, they may have played an important role in delivering volatile elements and organic material to the early Earth. Understanding how comets form can therefore provide a wealth of information on how the composition of volatile elements evolved in the solar system from the presolar molecular cloud up until the formation of the terrestrial planets. Because noble gases are chemically inert and have distinct condensation temperatures, they can be used to infer the temperatures of formation and thermal history of cometary ices. In this work, we present a new experimental setup called EXCITING to investigate the origin and formation conditions of cometary ices. By trapping nitrogen and noble gases in amorphous water ice, our experiment is designed to study the elemental and isotopic behavior of volatile elements in cometary ice analogs. We report new results of noble gas and nitrogen enrichment in cometary ice analogs and discuss the limitations of the experimental conditions in light of those supposed for comets. We show that forming ice analogs at \^{a}`u70 K best reproduce the noble gas and N2 abundances of comet 67P/Churyumov--Gerasimenko, considering a solar-like starting composition. This formation temperature is higher than previous estimates for cometary ices and suggests that the formation of cometary building blocks may have occurred in the protosolar nebula rather than in the colder molecular cloud.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Comets represent some of the most pristine bodies in our solar system and can provide a unique insight into the chemical makeup of the early solar system. Due to their icy volatile-rich nature, they may have played an important role in delivering volatile elements and organic material to the early Earth. Understanding how comets form can therefore provide a wealth of information on how the composition of volatile elements evolved in the solar system from the presolar molecular cloud up until the formation of the terrestrial planets. Because noble gases are chemically inert and have distinct condensation temperatures, they can be used to infer the temperatures of formation and thermal history of cometary ices. In this work, we present a new experimental setup called EXCITING to investigate the origin and formation conditions of cometary ices. By trapping nitrogen and noble gases in amorphous water ice, our experiment is designed to study the elemental and isotopic behavior of volatile elements in cometary ice analogs. We report new results of noble gas and nitrogen enrichment in cometary ice analogs and discuss the limitations of the experimental conditions in light of those supposed for comets. We show that forming ice analogs at â`u70 K best reproduce the noble gas and N2 abundances of comet 67P/Churyumov--Gerasimenko, considering a solar-like starting composition. This formation temperature is higher than previous estimates for cometary ices and suggests that the formation of cometary building blocks may have occurred in the protosolar nebula rather than in the colder molecular cloud. |
Barosch, J., Nittler, L. R., Wang, J., D’Alexander, C. M. O., Gregorio, B. T. De, Piani, L. Presolar Stardust in Asteroid Ryugu (Article de journal) Dans: The Astrophysical Journal Letters, vol. 935, no. L3, 2022. @article{Barosch_etal2022,
title = {Presolar Stardust in Asteroid Ryugu},
author = {J. Barosch and L. R. Nittler and J. Wang and C. M. O. D’Alexander and B. T. De Gregorio and L. Piani},
doi = {10.3847/2041-8213/ac83bd},
year = {2022},
date = {2022-01-01},
urldate = {2022-01-01},
journal = {The Astrophysical Journal Letters},
volume = {935},
number = {L3},
abstract = {We have conducted a NanoSIMS-based search for presolar material in samples recently returned from C-type asteroid Ryugu as part of JAXA\^{E}¼s Hayabusa2 mission. We report the detection of all major presolar grain types with O- and C-anomalous isotopic compositions typically identified in carbonaceous chondrite meteorites: 1 silicate, 1 oxide, 1 O-anomalous supernova grain of ambiguous phase, 38 SiC, and 16 carbonaceous grains. At least two of the carbonaceous grains are presolar graphites, whereas several grains with moderate C isotopic anomalies are probably organics. The presolar silicate was located in a clast with a less altered lithology than the typical extensively aqueously altered Ryugu matrix. The matrix-normalized presolar grain abundances in Ryugu are 4.8 2.6 4.7 ?\"{A}¬ + ppm for O-anomalous grains, 25 5 6 ?\"{A}¬ + ppm for SiC grains, and 11 3 5 ?\"{A}¬ + ppm for carbonaceous grains. Ryugu is isotopically and petrologically similar to carbonaceous Ivuna-type (CI) chondrites. To compare the in situ presolargrain abundances of Ryugu with CI chondrites, we also mapped Ivuna and Orgueil samples and found a total of 15 SiC grains and 6 carbonaceous grains. No O-anomalous grains were detected. The matrix-normalized presolar grain abundances in the CI chondrites are similar to those in Ryugu: 23 6 7 ?\"{A}¬ + ppm SiC and 9.0 3.65.4 ?\"{A}¬ + ppm carbonaceous grains. Thus, our results provide further evidence in support of the Ryugu--CI connection. They also reveal intriguing hints of small-scale heterogeneities in the Ryugu samples, such as locally distinct degrees of alteration that allowed the preservation of delicate presolar material.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We have conducted a NanoSIMS-based search for presolar material in samples recently returned from C-type asteroid Ryugu as part of JAXAʼs Hayabusa2 mission. We report the detection of all major presolar grain types with O- and C-anomalous isotopic compositions typically identified in carbonaceous chondrite meteorites: 1 silicate, 1 oxide, 1 O-anomalous supernova grain of ambiguous phase, 38 SiC, and 16 carbonaceous grains. At least two of the carbonaceous grains are presolar graphites, whereas several grains with moderate C isotopic anomalies are probably organics. The presolar silicate was located in a clast with a less altered lithology than the typical extensively aqueously altered Ryugu matrix. The matrix-normalized presolar grain abundances in Ryugu are 4.8 2.6 4.7 ?Ĭ + ppm for O-anomalous grains, 25 5 6 ?Ĭ + ppm for SiC grains, and 11 3 5 ?Ĭ + ppm for carbonaceous grains. Ryugu is isotopically and petrologically similar to carbonaceous Ivuna-type (CI) chondrites. To compare the in situ presolargrain abundances of Ryugu with CI chondrites, we also mapped Ivuna and Orgueil samples and found a total of 15 SiC grains and 6 carbonaceous grains. No O-anomalous grains were detected. The matrix-normalized presolar grain abundances in the CI chondrites are similar to those in Ryugu: 23 6 7 ?Ĭ + ppm SiC and 9.0 3.65.4 ?Ĭ + ppm carbonaceous grains. Thus, our results provide further evidence in support of the Ryugu--CI connection. They also reveal intriguing hints of small-scale heterogeneities in the Ryugu samples, such as locally distinct degrees of alteration that allowed the preservation of delicate presolar material. |
Moynier, F., Dai, W., Yokoyama, T., Piani, L. The Solar System calcium isotopic composition inferred from Ryugu samples (Article de journal) Dans: Geochemical Perspectives Letters, vol. 24, 2022. @article{Moynier_etal2022,
title = {The Solar System calcium isotopic composition inferred from Ryugu samples},
author = {F. Moynier and W. Dai and T. Yokoyama and L. Piani},
doi = {10.7185/geochemlet.2238},
year = {2022},
date = {2022-01-01},
urldate = {2022-01-01},
journal = {Geochemical Perspectives Letters},
volume = {24},
abstract = {The Hayabusa2 spacecraft has returned samples from the Cb-type asteroid (162173) Ryugu to Earth. Previous petrological and chemical analyses support a close link between Ryugu and CI chondrites that are presumed to be chemically the most primitive meteorites with a solar-like composition. However, Ryugu samples are highly enriched in Ca compared to typical CI chondrites. To identify the cause of this discrepancy, here we report stable Ca isotopic data (expressed as $delta$44/40CaSRM915a) for returned Ryugu samples collected from two sites. We found that samples from both sites have similar $delta$44/40CaSRM915a (0.58thinspacetextpmthinspace0.03 texttenthousand and 0.55thinspacetextpmthinspace0.08 texttenthousand, 2 s.d.) that fall within the range defined by CIs. This isotopic similarity suggests that the Ca budget of CIs and Ryugu samples is dominated by carbonates, and the variably higher Ca contents in Ryugu samples are due to the abundant carbonates. Precipitation of carbonates on Ryugu likely coincided with a major episode of aqueous activity dated to have occurred \^{a}`u5 Myr after Solar System formation. Based on the pristine Ryugu samples, the average $delta$44/40CaSRM915a of the Solar System is defined to be 0.57thinspacetextpmthinspace0.04 texttenthousand (2 s.d.).},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The Hayabusa2 spacecraft has returned samples from the Cb-type asteroid (162173) Ryugu to Earth. Previous petrological and chemical analyses support a close link between Ryugu and CI chondrites that are presumed to be chemically the most primitive meteorites with a solar-like composition. However, Ryugu samples are highly enriched in Ca compared to typical CI chondrites. To identify the cause of this discrepancy, here we report stable Ca isotopic data (expressed as $delta$44/40CaSRM915a) for returned Ryugu samples collected from two sites. We found that samples from both sites have similar $delta$44/40CaSRM915a (0.58thinspacetextpmthinspace0.03 texttenthousand and 0.55thinspacetextpmthinspace0.08 texttenthousand, 2 s.d.) that fall within the range defined by CIs. This isotopic similarity suggests that the Ca budget of CIs and Ryugu samples is dominated by carbonates, and the variably higher Ca contents in Ryugu samples are due to the abundant carbonates. Precipitation of carbonates on Ryugu likely coincided with a major episode of aqueous activity dated to have occurred â`u5 Myr after Solar System formation. Based on the pristine Ryugu samples, the average $delta$44/40CaSRM915a of the Solar System is defined to be 0.57thinspacetextpmthinspace0.04 texttenthousand (2 s.d.). |
Yokoyama, T., Nagashima, K., Nakai, I., Young, E. D., Abe, Y., Aléon, J., Alexander, C. M. O’D, Amari, S., Amelin, Y., Bajo, K., Bizzarro, M., Bouvier, A., Carlson, R. W., Chaussidon, M., Choi, B. G., Dauphas, N., Davis, A. M., Rocco, T. Di, Fujiya, W., Fukai, R., Gautam, I., Haba, M. K., Hibiya, Y., Hidaka, H., Homma, H., Hoppe, P., Huss, G. R., Ichida, K., Iizuka, T., Ireland, T. R., Ishikawa, A., Ito, M., Itoh, S., Kawasaki, N., Kita, N. T., Kitajima, K., Kleine, T., Komatani, S., Krot, A. N., Liu, M. C., Masuda, Y., McKeegan, K. D., Morita, M., Motomura, K., Moynier, F., Nguyen, A., Nittler, L., Onose, M., Pack, P., Park, C., Piani, L. Samples returned from the asteroid Ryugu are similar to Ivuna-type carbonaceous meteorites (Article de journal) Dans: Science, 2022. @article{Yokoyama_etal2022,
title = {Samples returned from the asteroid Ryugu are similar to Ivuna-type carbonaceous meteorites},
author = {T. Yokoyama and K. Nagashima and I. Nakai and E. D. Young and Y. Abe and J. Al\'{e}on and C. M. O’D Alexander and S. Amari and Y. Amelin and K. Bajo and M. Bizzarro and A. Bouvier and R. W. Carlson and M. Chaussidon and B. G. Choi and N. Dauphas and A. M. Davis and T. Di Rocco and W. Fujiya and R. Fukai and I. Gautam and M. K. Haba and Y. Hibiya and H. Hidaka and H. Homma and P. Hoppe and G. R. Huss and K. Ichida and T. Iizuka and T. R. Ireland and A. Ishikawa and M. Ito and S. Itoh and N. Kawasaki and N. T. Kita and K. Kitajima and T. Kleine and S. Komatani and A. N. Krot and M. C. Liu and Y. Masuda and K. D. McKeegan and M. Morita and K. Motomura and F. Moynier and A. Nguyen and L. Nittler and M. Onose and P. Pack and C. Park and L. Piani},
doi = {10.1126/science.abn7850},
year = {2022},
date = {2022-01-01},
urldate = {2022-01-01},
journal = {Science},
abstract = {Carbonaceous meteorites are thought to be fragments of C-type (carbonaceous) asteroids. Samples of the C-type asteroid (162173) Ryugu were retrieved by the Hayabusa2 spacecraft. We measure the mineralogy, bulk chemical and isotopic compositions of Ryugu samples. They are mainly composed of materials similar to carbonaceous chondrite meteorites, particularly the CI (Ivuna-type) group. The samples consist predominantly of minerals formed in aqueous fluid on a parent planetesimal. The primary minerals were altered by fluids at a temperature of 37 textpm 10textdegreeC, 5.2+0.7\^{a}0.8 (Stat.) +1.6\^{a}2.1 (Syst.) million years after formation of the first solids in the Solar System. After aqueous alteration, the Ryugu samples were likely never heated above textasciitilde100textdegreeC. The samples have a chemical composition that more closely resembles the Sun’s photosphere than other natural samples do.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Carbonaceous meteorites are thought to be fragments of C-type (carbonaceous) asteroids. Samples of the C-type asteroid (162173) Ryugu were retrieved by the Hayabusa2 spacecraft. We measure the mineralogy, bulk chemical and isotopic compositions of Ryugu samples. They are mainly composed of materials similar to carbonaceous chondrite meteorites, particularly the CI (Ivuna-type) group. The samples consist predominantly of minerals formed in aqueous fluid on a parent planetesimal. The primary minerals were altered by fluids at a temperature of 37 textpm 10textdegreeC, 5.2+0.7â0.8 (Stat.) +1.6â2.1 (Syst.) million years after formation of the first solids in the Solar System. After aqueous alteration, the Ryugu samples were likely never heated above textasciitilde100textdegreeC. The samples have a chemical composition that more closely resembles the Sun’s photosphere than other natural samples do. |
Broadley, M. W., Bekaert, D. V., Piani, L., Füri, E., Marty, B. Origin of life-forming volatile elements in the inner Solar System (Article de journal) Dans: Nature, vol. 611, p. 245–255, 2022. @article{Broadley_etal2022,
title = {Origin of life-forming volatile elements in the inner Solar System},
author = {M. W. Broadley and D. V. Bekaert and L. Piani and E. F\"{u}ri and B. Marty},
doi = {10.1038/s41586-022-05276-x},
year = {2022},
date = {2022-01-01},
journal = {Nature},
volume = {611},
pages = {245--255},
abstract = {Volatile elements such as hydrogen, carbon, nitrogen and oxygen are essential ingredients to build habitable worlds like Earth, but their origin and evolution on terrestrial planets remain highly debated. Here we discuss the processes that distributed these elements throughout the early Solar System and how they then became incorporated into planetary building blocks. Volatiles on Earth and the other terrestrial planets appear to have been heterogeneously sourced from different Solar System reservoirs. The sources of planetary volatiles and the timing at which they were accreted to growing planets probably play a crucial role in controlling planet habitability.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Volatile elements such as hydrogen, carbon, nitrogen and oxygen are essential ingredients to build habitable worlds like Earth, but their origin and evolution on terrestrial planets remain highly debated. Here we discuss the processes that distributed these elements throughout the early Solar System and how they then became incorporated into planetary building blocks. Volatiles on Earth and the other terrestrial planets appear to have been heterogeneously sourced from different Solar System reservoirs. The sources of planetary volatiles and the timing at which they were accreted to growing planets probably play a crucial role in controlling planet habitability. |
Hopp, T., Dauphas, N., al.,, Piani, L. Ryugu’s nucleosynthetic heritage from the outskirts of the Solar System (Article de journal) Dans: Science Advances, vol. 8, p. eads8141, 2022. @article{Hopp_etal2022,
title = {Ryugu’s nucleosynthetic heritage from the outskirts of the Solar System},
author = {T. Hopp and N. Dauphas and al. and L. Piani },
doi = {10.1126/sciadv.add8141},
year = {2022},
date = {2022-01-01},
urldate = {2022-01-01},
journal = {Science Advances},
volume = {8},
pages = {eads8141},
abstract = {Little is known about the origin of the spectral diversity of asteroids and what it says about conditions in the proto-planetary disk. Here, we show that samples returned from Cb-type asteroid Ryugu have Fe isotopic anomalies indistinguishable from Ivuna-type (CI) chondrites, which are distinct from all other carbonaceous chondrites. Iron isotopes, therefore, demonstrate that Ryugu and CI chondrites formed in a reservoir that was different from the source regions of other carbonaceous asteroids. Growth and migration of the giant planets destabilized nearby planetesimals and ejected some inward to be implanted into the Main Belt. In this framework, most carbonaceous chondrites may have originated from regions around the birthplaces of Jupiter and Saturn, while the distinct isotopic composition of CI chondrites and Ryugu may reflect their formation further away in the disk, owing their presence in the inner Solar System to excitation by Uranus and Neptune.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Little is known about the origin of the spectral diversity of asteroids and what it says about conditions in the proto-planetary disk. Here, we show that samples returned from Cb-type asteroid Ryugu have Fe isotopic anomalies indistinguishable from Ivuna-type (CI) chondrites, which are distinct from all other carbonaceous chondrites. Iron isotopes, therefore, demonstrate that Ryugu and CI chondrites formed in a reservoir that was different from the source regions of other carbonaceous asteroids. Growth and migration of the giant planets destabilized nearby planetesimals and ejected some inward to be implanted into the Main Belt. In this framework, most carbonaceous chondrites may have originated from regions around the birthplaces of Jupiter and Saturn, while the distinct isotopic composition of CI chondrites and Ryugu may reflect their formation further away in the disk, owing their presence in the inner Solar System to excitation by Uranus and Neptune. |
Kawasaki, N., Nagashima, K., Sakamoto, N., al.,, Piani, L. Oxygen isotopes of anhydrous primary minerals show kinship between asteroid Ryugu and comet 81P/Wild2 (Article de journal) Dans: Science Advances, vol. 8, no. 50, 2022. @article{Kawasaki_etal2022,
title = {Oxygen isotopes of anhydrous primary minerals show kinship between asteroid Ryugu and comet 81P/Wild2},
author = {N. Kawasaki and K. Nagashima and N. Sakamoto and al. and L. Piani},
doi = {10.1126/sciadv.ade2067},
year = {2022},
date = {2022-01-01},
urldate = {2022-01-01},
journal = {Science Advances},
volume = {8},
number = {50},
abstract = {The extraterrestrial materials returned from asteroid (162173) Ryugu consist predominantly of low-temperature aqueously formed secondary minerals and are chemically and mineralogically similar to CI (Ivuna-type) carbonaceous chondrites. Here, we show that high-temperature anhydrous primary minerals in Ryugu and CI chondrites exhibit a bimodal distribution of oxygen isotopic compositions: 16O-rich (associated with refractory inclusions) and 16O-poor (associated with chondrules). Both the 16O-rich and 16O-poor minerals probably formed in the inner solar protoplanetary disk and were subsequently transported outward. The abundance ratios of the 16O-rich to 16O-poor minerals in Ryugu and CI chondrites are higher than in other carbonaceous chondrite groups but are similar to that of comet 81P/Wild2, suggesting that Ryugu and CI chondrites accreted in the outer Solar System closer to the accretion region of comets.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The extraterrestrial materials returned from asteroid (162173) Ryugu consist predominantly of low-temperature aqueously formed secondary minerals and are chemically and mineralogically similar to CI (Ivuna-type) carbonaceous chondrites. Here, we show that high-temperature anhydrous primary minerals in Ryugu and CI chondrites exhibit a bimodal distribution of oxygen isotopic compositions: 16O-rich (associated with refractory inclusions) and 16O-poor (associated with chondrules). Both the 16O-rich and 16O-poor minerals probably formed in the inner solar protoplanetary disk and were subsequently transported outward. The abundance ratios of the 16O-rich to 16O-poor minerals in Ryugu and CI chondrites are higher than in other carbonaceous chondrite groups but are similar to that of comet 81P/Wild2, suggesting that Ryugu and CI chondrites accreted in the outer Solar System closer to the accretion region of comets. |
Paquet, M., Moynier, F., Yokoyama, T., al.,, Piani, L. Contribution of Ryugu-like material to Earth’s volatile inventory by Cu and Zn isotopic analysis (Article de journal) Dans: Nature Astronomy, 2022. @article{Paquet_etal2022,
title = {Contribution of Ryugu-like material to Earth’s volatile inventory by Cu and Zn isotopic analysis},
author = {M. Paquet and F. Moynier and T. Yokoyama and al. and L. Piani},
doi = {10.1038/s41550-022-01846-1},
year = {2022},
date = {2022-01-01},
urldate = {2022-01-01},
journal = {Nature Astronomy},
abstract = {Initial analyses showed that asteroid Ryugu’s composition is close to CI (Ivuna-like) carbonaceous chondrites (CCs) -- the chemically most primitive meteorites, characterized by near-solar abundances for most elements. However, some isotopic signatures (for example, Ti, Cr) overlap with other CC groups, so the details of the link between Ryugu and the CI chondrites are not yet fully clear. Here we show that Ryugu and CI chondrites have the same zinc and copper isotopic composition. As the various chondrite groups have very distinct Zn and Cu isotopic signatures, our results point at a common genetic heritage between Ryugu and CI chondrites, ruling out any affinity with other CC groups. Since Ryugu’s pristine samples match thesolar elemental composition for many elements, their Zn and Cu isotopic compositions likely represent the best estimates of the solar composition. Earth’s mass-independent Zn isotopic composition is intermediate between Ryugu/CC and non-carbonaceous chondrites (NCs), suggesting a contribution of Ryugu-like material to Earth’s budgets of Zn and other moderately volatile elements.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Initial analyses showed that asteroid Ryugu’s composition is close to CI (Ivuna-like) carbonaceous chondrites (CCs) -- the chemically most primitive meteorites, characterized by near-solar abundances for most elements. However, some isotopic signatures (for example, Ti, Cr) overlap with other CC groups, so the details of the link between Ryugu and the CI chondrites are not yet fully clear. Here we show that Ryugu and CI chondrites have the same zinc and copper isotopic composition. As the various chondrite groups have very distinct Zn and Cu isotopic signatures, our results point at a common genetic heritage between Ryugu and CI chondrites, ruling out any affinity with other CC groups. Since Ryugu’s pristine samples match thesolar elemental composition for many elements, their Zn and Cu isotopic compositions likely represent the best estimates of the solar composition. Earth’s mass-independent Zn isotopic composition is intermediate between Ryugu/CC and non-carbonaceous chondrites (NCs), suggesting a contribution of Ryugu-like material to Earth’s budgets of Zn and other moderately volatile elements. |
2021
|
Bouden, N., Villeneuve, J., Marrocchi, Y., Deloule, E., Füri, E., Gurenko, A., Piani, L., Thomassot, E., Peres, P., Fernandes, F. Triple oxygen isotope measurements by multi-collector secondary ion mass spectrometry (Article de journal) Dans: Frontiers in Earth Science, p. 8:601169, 2021. @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}
}
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$Ømega$ 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. |
Piani, L., Marrocchi, Y., Vacher, L. G., Yurimoto, H., Bizzarro, M. Origin of hydrogen isotopic variations in chondritic water and organics (Article de journal) Dans: Earth and Planetary Science Letters, p. 117008, 2021. @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}
}
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. |
2020
|
Marrocchi, Y., Bonal, L., Gattacceca, J., Piani, L., Beck, P., Greenwood, R., Eschrig, J., Basque, A., Nuccio, P. M., Martin, F. F. The Piancaldoli meteorite : A forgotten primitive LL3.10 ordinary chondrite (Article de journal) Dans: Meteoritics & Planetary Science, vol. 55, no. 8, p. 1924–1935, 2020. @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}
}
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. |
Piani, L., Marrocchi, Y., Rigaudier, T., Vacher, L. G., Thomassin, D., Marty, B. Earthtextquoterights water may have been inherited from material similar to enstatite chondrite meteorites (Article de journal) Dans: Science, vol. 369, no. 6507, p. 1110–1113, 2020. @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}
}
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. |
Piralla, M., Marrocchi, Y., Verdier-Paoletti, M. J., Vacher, L. G., Villeneuve, J., Piani, L., Bekaert, D. V., Gounelle, M. Primordial water and dust of the Solar System: Insights from in situ oxygen measurements of CI chondrites (Article de journal) Dans: Geochimica et Cosmochimica Acta, vol. 269, p. 451–464, 2020. @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}
}
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. |
Vacher, L., Piani, L., Rigaudier, T., Thomassin, D., Florin, G., Piralla, M., Marrocchi, Y. Hydrogen in chondrites: Influence of parent body alteration and atmospheric contamination on primordial components (Article de journal) Dans: Geochimica et Cosmochimica Acta, vol. 281, p. 53–66, 2020. @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}
}
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 |
2019
|
Dalou, C., Füri, E., Deligny, C., Piani, L., Caumon, G., Laumonier, B., Boulliung, J., Edén, M. Redox control on nitrogen isotope fractionation during planetary core formation (Article de journal) Dans: Proceedings of the National Academy of Sciences of the United States of America, 2019. @article{Dalou_etal2019,
title = {Redox control on nitrogen isotope fractionation during planetary core formation},
author = {C. Dalou and E. F\"{u}ri and C. Deligny and L. Piani and G. Caumon and B. Laumonier and J. Boulliung and M. Ed\'{e}n},
doi = {10.1073/pnas.1820719116},
year = {2019},
date = {2019-01-01},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
abstract = {The present-day nitrogen isotopic compositions of Earthtextquoterights surficial (15N-enriched) and deep reservoirs (15N-depleted) differ significantly. This distribution can neither be explained by modern mantle degassing nor recycling via subduction zones. As the effect of planetary differentiation on the behavior of N isotopes is poorlyunderstood, we experimentally determined N-isotopic fractionations during metal--silicate partitioning (analogous to planetary core formation) over a large range of oxygen fugacities ($Delta$IW −3.1 \< logfO2 \< $Delta$IW −0.5, where $Delta$IW is the logarithmicdifference between experimental oxygen fugacity [fO2] conditions and that imposed by the coexistence of iron and wüstite) at 1 GPa and 1,400 textdegreeC. We developed an in situ analytical method to measure the N-elemental and -isotopic compositions of experimental run products composed of Fe--C--N metal alloys and basaltic melts.Our results show substantial N-isotopic fractionations between metal alloys and silicate glasses, i.e., from −257 textpm 22texttenthousand to −49 textpm 1texttenthousand over 3 log units of fO2. These large fractionations under reduced conditions can be explained by the large difference between N bonding in metal alloys (Fe--N) and in silicate glasses (asmolecular N2 and NH complexes). We show that the $delta$15N value of the silicate mantle could have increased by �`u20texttenthousand during core formation due to N segregation into the core.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The present-day nitrogen isotopic compositions of Earthtextquoterights surficial (15N-enriched) and deep reservoirs (15N-depleted) differ significantly. This distribution can neither be explained by modern mantle degassing nor recycling via subduction zones. As the effect of planetary differentiation on the behavior of N isotopes is poorlyunderstood, we experimentally determined N-isotopic fractionations during metal--silicate partitioning (analogous to planetary core formation) over a large range of oxygen fugacities ($Delta$IW −3.1 < logfO2 < $Delta$IW −0.5, where $Delta$IW is the logarithmicdifference between experimental oxygen fugacity [fO2] conditions and that imposed by the coexistence of iron and wüstite) at 1 GPa and 1,400 textdegreeC. We developed an in situ analytical method to measure the N-elemental and -isotopic compositions of experimental run products composed of Fe--C--N metal alloys and basaltic melts.Our results show substantial N-isotopic fractionations between metal alloys and silicate glasses, i.e., from −257 textpm 22texttenthousand to −49 textpm 1texttenthousand over 3 log units of fO2. These large fractionations under reduced conditions can be explained by the large difference between N bonding in metal alloys (Fe--N) and in silicate glasses (asmolecular N2 and NH complexes). We show that the $delta$15N value of the silicate mantle could have increased by �`u20texttenthousand during core formation due to N segregation into the core. |
Isono, Y., Tachibana, S., Naraoka, H., Orthous-Daunay, F. R., Piani, L., Kebukawa, Y. Bulk chemical characteristics of soluble polar organic molecules formed through condensation of formaldehyde: Comparison with soluble organic molecules in Murchison meteorite (Article de journal) Dans: Geochemical Journal, vol. 53, p. 41–51, 2019. @article{Isono_etal2019,
title = {Bulk chemical characteristics of soluble polar organic molecules formed through condensation of formaldehyde: Comparison with soluble organic molecules in Murchison meteorite},
author = {Y. Isono and S. Tachibana and H. Naraoka and F. R. Orthous-Daunay and L. Piani and Y. Kebukawa},
doi = {10.2343/geochemj.2.0551},
year = {2019},
date = {2019-01-01},
journal = {Geochemical Journal},
volume = {53},
pages = {41--51},
abstract = {Carbonaceous chondrites contain up to 2 wt% organic carbon, which is present as acid and solvent insoluble solid organic matter (IOM) and solvent soluble organic matter (SOM). The extraterrestrial organic matter should record chemical processes occurred in different environments in the early history of the Solar System, and the role of parent body aqueous alteration in the synthesis or subsequent modification of IOM and SOM still requires accurate constraints. We conducted hydrothermal experiments to simulate the synthesis of organic molecules during aqueous alteration on small bodies. Bulk chemical characteristics of soluble organic matter synthesized from formaldehyde in aqueous solutions were studied to compare them with that of chondritic SOM. We found that the redox state of synthesized organic molecules depends on temperature; the molecules become richer in hydrogen at higher temperatures. This can be explained by a cross-disproportionation reaction between organic molecules and formic acid, which occurs as a side reaction of the aldol condensation and works more effectively at higher temperatures. Comparison of the bulk chemical characteristics between the synthesized molecules and SOM extracted from the Murchison meteorite with methanol shows that the solubleorganic molecules in Murchison are more reduced than the synthesized molecules. Considering the temperature condition for aqueous alteration on the CM parent body that is lower than or equivalent to the experimental temperatures, thereduced nature of Murchison organic molecules requires a reducing environment for them to be formed during hydrothermal alteration or imply that processes other than hydrothermal alteration were responsible for their synthesis. In case ofhydrothermal synthesis, reducing conditions might be established by the interaction between water and iron-bearing silicates or metals on the parent body.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Carbonaceous chondrites contain up to 2 wt% organic carbon, which is present as acid and solvent insoluble solid organic matter (IOM) and solvent soluble organic matter (SOM). The extraterrestrial organic matter should record chemical processes occurred in different environments in the early history of the Solar System, and the role of parent body aqueous alteration in the synthesis or subsequent modification of IOM and SOM still requires accurate constraints. We conducted hydrothermal experiments to simulate the synthesis of organic molecules during aqueous alteration on small bodies. Bulk chemical characteristics of soluble organic matter synthesized from formaldehyde in aqueous solutions were studied to compare them with that of chondritic SOM. We found that the redox state of synthesized organic molecules depends on temperature; the molecules become richer in hydrogen at higher temperatures. This can be explained by a cross-disproportionation reaction between organic molecules and formic acid, which occurs as a side reaction of the aldol condensation and works more effectively at higher temperatures. Comparison of the bulk chemical characteristics between the synthesized molecules and SOM extracted from the Murchison meteorite with methanol shows that the solubleorganic molecules in Murchison are more reduced than the synthesized molecules. Considering the temperature condition for aqueous alteration on the CM parent body that is lower than or equivalent to the experimental temperatures, thereduced nature of Murchison organic molecules requires a reducing environment for them to be formed during hydrothermal alteration or imply that processes other than hydrothermal alteration were responsible for their synthesis. In case ofhydrothermal synthesis, reducing conditions might be established by the interaction between water and iron-bearing silicates or metals on the parent body. |
Kouchi, A., Tachibana, S., Piani, L., Orthous-Daunay, F. R., Naraoka, H. Preface: Evolution of molecules in space: From interstellar clouds to protoplanetary nebulae (Article de journal) Dans: Geochemical Journal, vol. 53, no. 1, p. 1–3, 2019. @article{Kouchi_etal2019,
title = {Preface: Evolution of molecules in space: From interstellar clouds to protoplanetary nebulae},
author = {A. Kouchi and S. Tachibana and L. Piani and F. R. Orthous-Daunay and H. Naraoka},
doi = {10.2343/geochemj.2.0555},
year = {2019},
date = {2019-01-01},
journal = {Geochemical Journal},
volume = {53},
number = {1},
pages = {1--3},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
|
Marrocchi, Y., Piani, L. The tumultuous childhood of the Solar System (Article de journal) Dans: Nature Astronomy, vol. 3, no. 10, p. 889–890, 2019. @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}
}
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. |
Orthous-Daunay, F. R., Piani, L., Flandinet, L., Thissen, R., Wolters, C., Vuitton, V., Poch, O., Moynier, F., Sugawara, I., Naraoka, H., Tachibana, S. Ultraviolet-photon fingerprints on chondritic large organic molecules (Article de journal) Dans: Geochemical Journal, vol. 53, no. 32, p. 21–32, 2019. @article{Orthous-Daunay_etal2019,
title = {Ultraviolet-photon fingerprints on chondritic large organic molecules},
author = {F. R. Orthous-Daunay and L. Piani and L. Flandinet and R. Thissen and C. Wolters and V. Vuitton and O. Poch and F. Moynier and I. Sugawara and H. Naraoka and S. Tachibana},
doi = {10.2343/geochemj.2.0544},
year = {2019},
date = {2019-01-01},
journal = {Geochemical Journal},
volume = {53},
number = {32},
pages = {21--32},
abstract = {The organic matter in carbonaceous chondrites is of two kinds : one is called Insoluble Organic Matter, made of extremely large molecules that cannot be named with the usual nomenclature ; one can be extracted by laboratory solvents and analyzed as a molecular mixture. Both are of debated origin. Retracing their natural histories requires putting strong constraints on their possible place of birth and their life time in space environments. It cannot be excluded they were formed in an interstellar medium before accretion on the chondritic parent bodies. As ultraviolet rays are the most common in the star forming regions and during the accretion phase of solar system, we propose to test the resilience of the natural organic matter of the Murchison meteorite against photolysis. The meteoritical soluble molecules were extracted by maceration and artificially exposed to a La photon dose commensurate to the one expected in molecular clouds and disks. The gaseous photolysis products were analyzed on the fly whereas the solid state mixture was solubilized again after irradiation for Orbitrap High Resolution Mass Spectrometry monitoring. We found that ultraviolet photons do modify the molecular mixture, removing H2 and small carbon bearing species, shifting the mass distribution toward lower masses and increasing the number of cycles and double bonds in the molecules structure. A noteworthy effect of the irradiation is its selective preservation of species with a double bond equivalent consistent with aromatic rings in their structure. This is explained by the higher stability of such compounds. As the pristine Murchison extract lacks those features, we estimate it has not undergone significant irradiation after its synthesis. The extract we used for experiment being water insoluble, we assume its reactivity in hydrothermal condition would have been limited and have had no effect on the irradiation fingerprints. As a result the soluble fraction of Murchison was whether formed where the UV photon flux was negligible or it has been accreted quickly and shielded from photolysis in a parent body.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The organic matter in carbonaceous chondrites is of two kinds : one is called Insoluble Organic Matter, made of extremely large molecules that cannot be named with the usual nomenclature ; one can be extracted by laboratory solvents and analyzed as a molecular mixture. Both are of debated origin. Retracing their natural histories requires putting strong constraints on their possible place of birth and their life time in space environments. It cannot be excluded they were formed in an interstellar medium before accretion on the chondritic parent bodies. As ultraviolet rays are the most common in the star forming regions and during the accretion phase of solar system, we propose to test the resilience of the natural organic matter of the Murchison meteorite against photolysis. The meteoritical soluble molecules were extracted by maceration and artificially exposed to a La photon dose commensurate to the one expected in molecular clouds and disks. The gaseous photolysis products were analyzed on the fly whereas the solid state mixture was solubilized again after irradiation for Orbitrap High Resolution Mass Spectrometry monitoring. We found that ultraviolet photons do modify the molecular mixture, removing H2 and small carbon bearing species, shifting the mass distribution toward lower masses and increasing the number of cycles and double bonds in the molecules structure. A noteworthy effect of the irradiation is its selective preservation of species with a double bond equivalent consistent with aromatic rings in their structure. This is explained by the higher stability of such compounds. As the pristine Murchison extract lacks those features, we estimate it has not undergone significant irradiation after its synthesis. The extract we used for experiment being water insoluble, we assume its reactivity in hydrothermal condition would have been limited and have had no effect on the irradiation fingerprints. As a result the soluble fraction of Murchison was whether formed where the UV photon flux was negligible or it has been accreted quickly and shielded from photolysis in a parent body. |
2018
|
Marrocchi, Y., Bekaert, D. V., Piani, L. Origin and abundance of water in carbonaceous asteroids (Article de journal) Dans: Earth and Planetary Science Letters, vol. 482, p. 23–32, 2018. @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$m such as presolar grains. Among carbonaceous chondrites, CV chondrites show O-isotopic features suggesting potential contribution of 17--18O-rich water that may be related to their older accretion relative to other hydrated carbonaceous chondrites.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The origin and abundance of water accreted by carbonaceous asteroids remains underconstrained, but would provide important information on the dynamic of the protoplanetary disk. Here we report the in situoxygen isotopic compositions of aqueously formed fayalite grains in the Kaba and Mokoia CV chondrites. CV chondrite bulk, matrix and fayalite O-isotopic compositions define the mass-independent continuous trend ($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. |
Marrocchi, Y., Villeneuve, J., Batanova, V., Piani, L., Jacquet, E. Oxygen isotopic diversity of chondrule precursors and the nebular origin of chondrules (Article de journal) Dans: Earth and Planetary Science Letters, vol. 496, p. 132–141, 2018. @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}
}
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. |
Piani, L., Marrocchi, Y. Hydrogen isotopic composition of water in CV-type carbonaceous chondrites (Article de journal) Dans: Earth and Planetary Science Letters, vol. 504, p. 64–71, 2018. @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}
}
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. |
Piani, L., Yurimoto, H., Remusat, L. A dual origin for water in carbonaceous asteroids revealed by CM chondrites (Article de journal) Dans: Nature Astronomy, no. 2, p. 317–323, 2018. @article{Piani_etal2018,
title = {A dual origin for water in carbonaceous asteroids revealed by CM chondrites},
author = {L. Piani and H. Yurimoto and L. Remusat},
doi = {10.1038/s41550-018-0413-4},
year = {2018},
date = {2018-01-01},
journal = {Nature Astronomy},
number = {2},
pages = {317--323},
abstract = {Carbonaceous asteroids represent the principal source of water in the inner Solar System and might correspond to the main contributors for the delivery of water to Earth. Hydrogen isotopes in water-bearing primitive meteorites, for example carbonaceous chondrites, constitute a unique tool for deciphering the sources of water reservoirs at the time of asteroid formation. However, fine-scale isotopic measurements are required to unravel the effects of parent-body processes on the pre-accretion isotopic distributions. Here, we report in situ micrometre-scale analyses of hydrogen isotopes in six CM-type carbonaceous chondrites, revealing a dominant deuterium-poor water component ($delta$ D = − 350 textpm 40texttenthousand) mixed with deuterium-rich organic matter. We suggest that this deuterium-poor water corresponds to a ubiquitous water reservoir in the inner protoplanetarydisk. A deuterium-rich water signature has been preserved in the least altered part of the Paris chondrite ($delta$ DParis �W − 69 textpm 163texttenthousand) in hydrated phases possibly present in the CM rock before alteration. The presence of the deuterium-enriched water signature in Paris might indicate that transfers of ice from the outer to the inner Solar System were significant within the first million years of the history of the Solar System.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Carbonaceous asteroids represent the principal source of water in the inner Solar System and might correspond to the main contributors for the delivery of water to Earth. Hydrogen isotopes in water-bearing primitive meteorites, for example carbonaceous chondrites, constitute a unique tool for deciphering the sources of water reservoirs at the time of asteroid formation. However, fine-scale isotopic measurements are required to unravel the effects of parent-body processes on the pre-accretion isotopic distributions. Here, we report in situ micrometre-scale analyses of hydrogen isotopes in six CM-type carbonaceous chondrites, revealing a dominant deuterium-poor water component ($delta$ D = − 350 textpm 40texttenthousand) mixed with deuterium-rich organic matter. We suggest that this deuterium-poor water corresponds to a ubiquitous water reservoir in the inner protoplanetarydisk. A deuterium-rich water signature has been preserved in the least altered part of the Paris chondrite ($delta$ DParis �W − 69 textpm 163texttenthousand) in hydrated phases possibly present in the CM rock before alteration. The presence of the deuterium-enriched water signature in Paris might indicate that transfers of ice from the outer to the inner Solar System were significant within the first million years of the history of the Solar System. |
2017
|
Tachibana, S., Kouchi, A., Hama, T., Oba, Y., Piani, L. Liquid-like behavior of UV-irradiated interstellar ice analog at low temperatures (Article de journal) Dans: Science Advances, vol. 3, no. 9, p. eaao2538, 2017. @article{Tachibana_etal2017,
title = {Liquid-like behavior of UV-irradiated interstellar ice analog at low temperatures},
author = {S. Tachibana and A. Kouchi and T. Hama and Y. Oba and L. Piani},
doi = {10.1126/sciadv.aao2538},
year = {2017},
date = {2017-01-01},
journal = {Science Advances},
volume = {3},
number = {9},
pages = {eaao2538},
abstract = {Interstellar ice is believed to be a cradle of complex organic compounds, commonly found within icy comets and interstellar clouds, in association with ultraviolet (UV) irradiation and subsequent warming. We found that UV-irradiated amorphous ices composed of H2O, CH3OH, and NH3 and of pure H2O behave like liquids over the temperature ranges of 65 to 150 kelvin and 50 to 140 kelvin, respectively. This low-viscosity liquid-like ice may enhance the formation of organic compounds including prebiotic molecules and the accretion of icy dust to form icy planetesimals under certain interstellar conditions.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Interstellar ice is believed to be a cradle of complex organic compounds, commonly found within icy comets and interstellar clouds, in association with ultraviolet (UV) irradiation and subsequent warming. We found that UV-irradiated amorphous ices composed of H2O, CH3OH, and NH3 and of pure H2O behave like liquids over the temperature ranges of 65 to 150 kelvin and 50 to 140 kelvin, respectively. This low-viscosity liquid-like ice may enhance the formation of organic compounds including prebiotic molecules and the accretion of icy dust to form icy planetesimals under certain interstellar conditions. |
2016
|
Marrocchi, Y., Chaussidon, M., Piani, L., Libourel, G. Early scattering of the solar protoplanetary disk recorded in meteoritic chondrules (Article de journal) Dans: Science Advances, 2016. @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}
}
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. |
Piani, L., Marrocchi, Y., Libourel, G., Tissandier, L. Magmatic sulfides in the porphyritic chondrules of EH enstatite chondrites (Article de journal) Dans: Geochimica et Cosmochimica Acta, vol. 195, p. 84–99, 2016. @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}
}
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. |
2012
|
Piani, L., Robert, F., Beyssac, O., Binet, L., Bourot-Denise, M., Derenne, S., Guillou, C. Le, Marrocchi, Y., Mostefaoui, S., Rouzaud, J. N., Thomen, A. Structure, composition, and location of organic matter in the enstatite chondrite Sahara 97096 (EH3) (Article de journal) Dans: Meteoritics & Planetary Science, vol. 47, no. 1, p. 8–29, 2012. @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}
}
|
