Dynamic degassing of serpentine by impact process

Wednesday, 17 December 2014
Toshimori Sekine1, Tomoaki Kimura1, Takamichi Kobayashi2 and Tsutomu Mashimo3, (1)Hiroshima University, Higashi-Hiroshima, Japan, (2)National Institute for Materials Science, Tsukuba, Japan, (3)Kumamoto University, Kumamoto, Japan
Impact-induced dehydration of serpentine in primitive meteorites is believed to be a mechanism to provide water in terrestrial planets. Primitive meteorites show a wide range of porosity and it is necessary to know the effect of porosity on the dehydration. In this work we report the dynamic dehydration reaction of antigorite under various conditions using techniques of x-ray diffractions, electron microscopy, and thermal analyses of shock recovered samples. The present experimental results indicate that the dehydration reactions are weakly pressure-dependent below a peak shock pressure of ~21 GPa and becomes violent at pressures of 21-60 GPa dependent on the initial porosity and sample amount. We discuss the heterogeneous dehydration reactions based on the identified phases, more than previously thought.