Formation of high-pressure minerals in shocked L6 chondrite Yamato 791384: constraints on shock conditions and parent body size
Formation of high-pressure minerals in shocked L6 chondrite Yamato 791384: constraints on shock conditions and parent body size
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DOI：
10.1016/j.epsl.2004.08.018
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发表时间：
2004-11-15
影响因子：
5.3
通讯作者：
Kubo, T
中科院分区：
文献类型：
--
作者：
Ohtani, E;Kimura, Y;Kubo, T
我们研究了在Yamato 791384 L 6球粒陨石中观察到的高压相。寄主陨石主要由橄榄石、辉石和斜长石玻璃组成。在主陨石的脉和脉缘区域观察到的矿物碎片部分或全部转化为高压相; ringwoodite，majerite，akimotoite，NaAlSi 3 O 8 hollandite和硬玉。震脉基质中含有镁铝榴石-镁铝榴石固溶体。空间分布表明，高压相存在于震脉和与震脉相邻的容矿岩石中。对高压相的研究表明，在Y 791384中，碎片和邻近基质受到约18-23 GPa的压力，并且在冲击事件期间静脉经历了约2300摄氏度的温度。在与矿脉相邻的寄主橄榄石中观察到林伍德石薄片。橄榄石中林伍德石片层生长动力学研究表明，冲击陨石经历了至少4s的压力。如此长的压力脉冲持续时间表明母体的大小大于10公里。(C)2004 Elsevier B. V.保留所有权利。
We have studied the high-pressure phases observed in Yamato 791384 L6 chondrite. Host meteorite mainly consists of olivine, pyroxenes and plagioclase glass. Mineral fragments observed in the veins and the vein margin region of the host meteorite were partially or totally transformed into high-pressure phases; ringwoodite, majorite, akimotoite, NaAlSi3O8 hollandite and jadeite. Matrix of the shock vein contains majorite-pyrope solid solution. The spatial distribution indicates that high-pressure phases are present in the shock veins and host rocks adjacent to the shock veins. Investigation of the high-pressure phases revealed that, in Y791384, fragments and adjacent matrix were subjected to pressures around of 18-23 GPa and the vein experienced temperatures around 2300 degreesC during the shock event. Ringwoodite lamellae were observed in the host olivine adjacent to the vein. Kinetic investigation for ringwoodite lamellar growth in olivine indicates that the shocked meteorite experienced the pressure for at least 4 s. Such long duration of the pressure pulse indicates that the size of the parent body was greater than 10 km. (C) 2004 Elsevier B.V. All rights reserved.