The occurrence of γ phase, a high\|pressure polymorph of olivine （α phase）, in the shock veins of Si\| xiangkou chondrite was due to a greater cooling rate （>10 000℃·s -1 ） in the veins. Because γ phas...The occurrence of γ phase, a high\|pressure polymorph of olivine （α phase）, in the shock veins of Si\| xiangkou chondrite was due to a greater cooling rate （>10 000℃·s -1 ） in the veins. Because γ phase partially reverted to β phase and no back\|transformation from β phase to α phase took place, the shock veins of Peace River chondrite with a cooling rate of 1 000\2 000℃·s -1 contain a great amount of β phase. In the shock veins of Mbale chondrite with a cooling rate of <500℃·s -1 , the majority of γ phase reverted to α phase. The heat dissipation in shock veins took place after a stage of shock compression of chondrite parent body, and the parent body was broken into fragmental pieces. Cooling rate in the shock veins constrained the back\|transformations of （Mg,Fe）\-2SiO\-4 high\|pressure polymorphs.展开更多
文摘The occurrence of γ phase, a high\|pressure polymorph of olivine （α phase）, in the shock veins of Si\| xiangkou chondrite was due to a greater cooling rate （>10 000℃·s -1 ） in the veins. Because γ phase partially reverted to β phase and no back\|transformation from β phase to α phase took place, the shock veins of Peace River chondrite with a cooling rate of 1 000\2 000℃·s -1 contain a great amount of β phase. In the shock veins of Mbale chondrite with a cooling rate of <500℃·s -1 , the majority of γ phase reverted to α phase. The heat dissipation in shock veins took place after a stage of shock compression of chondrite parent body, and the parent body was broken into fragmental pieces. Cooling rate in the shock veins constrained the back\|transformations of （Mg,Fe）\-2SiO\-4 high\|pressure polymorphs.
