Dorian Thomassin

@article{Piani_etal2020,

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

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

doi = {10.1126/science.aba1948},

year  = {2020},

date = {2020-01-01},

journal = {Science},

volume = {369},

number = {6507},

pages = {1110--1113},

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

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{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}

}