TY - JOUR

T1 - Origin of hydrogen isotopic variations in chondritic water and organics

AU - Piani, Laurette

AU - Marrocchi, Yves

AU - Vacher, Lionel G.

AU - Yurimoto, Hisayoshi

AU - Bizzarro, Martin

PY - 2021

Y1 - 2021

N2 - 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 situ secondary 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. (C) 2021 Elsevier B.V. All rights reserved.

AB - 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 situ secondary 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. (C) 2021 Elsevier B.V. All rights reserved.

KW - chondrite

KW - water

KW - organic matter

KW - hydrogen isotopes

KW - disk

KW - molecular cloud

KW - CARBONACEOUS CHONDRITE

KW - PROTOPLANETARY DISKS

KW - CM CHONDRITE

KW - EVOLUTION

KW - FRACTIONATION

KW - ACCRETION

KW - METEORITE

KW - HISTORY

KW - MATTER

U2 - 10.1016/j.epsl.2021.117008

DO - 10.1016/j.epsl.2021.117008

M3 - Journal article

VL - 567

JO - Earth and Planetary Science Letters

JF - Earth and Planetary Science Letters

SN - 0012-821X

M1 - 117008

ER -