Characteristics in naturally and experimentally shocked chondrites: A clue to P-T conditions of impacted asteroids |
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Authors: | XIE Xiande CHEN Ming DAI Chengda A El Goresy |
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Institution: | 1. Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China 2. Max-Planck-Institute fur Chemie, Mainz 55128, Germany |
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Abstract: | The aim of this study is to compare the experimentally shock-induced features with those in naturally shocked chondrites and
to test the feasibility of experimentally calibrating naturally induced features in shocked H- and L-chondrites. Samples of
the Jilin chondrite (H5) were experimentally shock-loaded at the following peak pressures: 12, 27, 39, 53, 78, 83, 93 and
133 GPa respectively. Chondritic melts were first obtained at P>78 GPa and more than 60% melting was achieved at P~133 GPa.
No high-pressure phases were observed in any of the shocked samples, neither in the deformed nor in the molten regions. Textural
relations and mineral assemblages of the shocked samples are comparable to those encountered in the heavily shocked H-chondrite
Yanzhuang but differ considerably from those found in heavily shocked L6 chondrites. Shock melt veins in L6 chondrites contain
high-pressure polymorphs of olivine and pyroxene and high pressure liquidus phases. Scaling from shock experiments on millimeter-sized
samples to natural shock features on kilometer-sized asteroids poses considerable problems in quantifying the P-T conditions
during natural shock events on asteroids. |
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Keywords: | chondrite experiment shock characteristics asteroid P-T condition |
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