TY - JOUR
T1 - Shock-induced volatile loss from a carbonaceous chondrite
T2 - implications for planetary accretion
AU - Tyburczy, James A.
AU - Frisch, Benjamin
AU - Ahrens, Thomas J.
N1 - Funding Information:
Supported under NASA grant NGL-05-002-105. We are grateful to Professor Carleton Moore and the Center for Meteorite Studies, Arizona State Umverslty for samples. We appreciate the use of laboratory facihties operated by George Rossman and E.M. Stolper as well as helpful comments on the manuscript proffered by Wdham Anderson. Fred Horz and two anonymous reviewers provided constructive reviews Division of Geological and Planetary Sciences Contribution No. 4293
PY - 1986/11
Y1 - 1986/11
N2 - Solid-recovery impact-induced volatile loss experiments on the Murchison C2M meteorite indicate that for an impact of a given velocity, H2O and total volatiles are driven from the sample in the same proportion as present initially. We infer that the volatiles other than H2O driven from the meteorite also have the same bulk composition as those of the starting material. Thus, the early bulk composition of an impact-induced atmosphere of a planet growing by accretion from material like Murchison would be the same as the volatile composition of the incident planetesimals. Incipient devolatilization of Murchison occurs at an initial shock pressure of about 11 GPa and complete devolatilization occurs at a pressure of about 30 GPa. If an Earth-sized planet were formed from the infall of planetesimals of Murchison composition, incipient and complete devolatilization of accreting planetesimals would occur when the planet reached approximately 12% and 27%, respectively, of its final radius. Thus, impact-induced devolatilization of accreting planetesimals and of the hydrated surface would profoundly affect the distribution of volatiles within the accreting planet. For example, for a cold, homogeneous accretion of a planet, prior to metallic core formation and internal differentiation, the growing planet would have a very small core with the same volatile content as the incident material, a volatile-depleted "mantle", and an extremely volatile-rich surface.
AB - Solid-recovery impact-induced volatile loss experiments on the Murchison C2M meteorite indicate that for an impact of a given velocity, H2O and total volatiles are driven from the sample in the same proportion as present initially. We infer that the volatiles other than H2O driven from the meteorite also have the same bulk composition as those of the starting material. Thus, the early bulk composition of an impact-induced atmosphere of a planet growing by accretion from material like Murchison would be the same as the volatile composition of the incident planetesimals. Incipient devolatilization of Murchison occurs at an initial shock pressure of about 11 GPa and complete devolatilization occurs at a pressure of about 30 GPa. If an Earth-sized planet were formed from the infall of planetesimals of Murchison composition, incipient and complete devolatilization of accreting planetesimals would occur when the planet reached approximately 12% and 27%, respectively, of its final radius. Thus, impact-induced devolatilization of accreting planetesimals and of the hydrated surface would profoundly affect the distribution of volatiles within the accreting planet. For example, for a cold, homogeneous accretion of a planet, prior to metallic core formation and internal differentiation, the growing planet would have a very small core with the same volatile content as the incident material, a volatile-depleted "mantle", and an extremely volatile-rich surface.
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U2 - 10.1016/0012-821X(86)90104-4
DO - 10.1016/0012-821X(86)90104-4
M3 - Article
AN - SCOPUS:0022928698
SN - 0012-821X
VL - 80
SP - 201
EP - 207
JO - Earth and Planetary Science Letters
JF - Earth and Planetary Science Letters
IS - 3-4
ER -