Impact‐Induced Melting of Near‐Surface Water Ice on Mars
作者:
Sarah T. Stewart,
Thomas J. Ahrens,
John D. O’Keefe,
期刊:
AIP Conference Proceedings
(AIP Available online 1904)
卷期:
Volume 706,
issue 1
页码: 1484-1487
ISSN:0094-243X
年代: 1904
DOI:10.1063/1.1780519
出版商: AIP
数据来源: AIP
摘要:
All fresh and many older Martian craters with diameters greater than a few km are surrounded by ejecta blankets which appear fluidized, with morphologies believed to form by entrainment of liquid water. We present cratering simulations investigating the outcome of 10 km s−1impacts onto models of the Martian crust, a mixture of basalt and ice at an average temperature of 200 K. Because of the strong impedance mismatch between basalt and ice, the peak shock pressure and the pressure decay profiles are sensitive to the mixture composition of the surface. For typical impact events, about 50&percent; of the excavated ground ice is melted by the impact‐induced shock. Pre‐existing subsurface liquid water is not required to form observed fluidized ejecta morphologies, and the presence of rampart craters on different age terranes is a useful probe of ground ice on Mars over time. © 2004 American Institute of Physics
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