Shock metamorphism of ordinary chondrites from Grove Mountains, Antarctica |
| |
Authors: | Feng Lu Lin Yangting Hu Sen Liu Tao |
| |
Institution: | 1. Institute of Geology and Geophysics, Chinese Academy of Science, Beijing 100029, China 2. Guangzhou Institute of Geochemistry, Chinese Academy of Science, Guangzhou 510640, China |
| |
Abstract: | Shock effects of 93 Grove Mountains (GRV) ordinary chondrites were studied in this work, including fracture, various types of extinction, and recrystallization of silicates observed under optical microscopy. Shock-induced veins and pockets show various microtextures, decomposition and phase transformation of minerals. The confirmed high-pressure polymorphs of silicates are ringwoodite, majorite, pyroxene glass and maskelynite. Based on the shock effects and assemblages of high-pressure minerals, shock stages of all of 93 GRV chondrites were classified. In comparison with literature, the Grove Mountains meteorites have a higher fraction (23 out of 93) of heavily shocked samples (S4-S5). Most of the heavily shocked meteorites are L group (22 out of 23), except for one H chondrite. The distinct shock metamorphism between H and L groups may indicate different surface properties of their parent bodies. In addition, there is relationship between petrologic types and shock stages, with most heavily shocked samples observed in equilibrated ordinary chondrites (especially Type 5 and 6). |
| |
Keywords: | Antarctic Grove Mountains chondrites shock metamorphism high-pressure mineral |
本文献已被 维普 万方数据 等数据库收录! |
|