High-pressure investigations on Piplia Kalan eucrite meteorite using in-situ X-ray diffraction and ^(57)Fe Mssbauer spectroscopic technique up to 16 GPa

作     者：Usha Chandra K.K. Pandey G. Parthasarathy Surinder M. Sharma 

作者机构：Department of Physics University of Rajasthan Jaipur 302 004 India High Pressure & Synchrotron Radiation Physics Division Bhabha Atomic Research Centre Trombay Mumbai 400 085 India CSIR-National Geophysical Research Institute Uppal Road Hyderabad 500 007 India 

出 版 物：《Geoscience Frontiers》 (地学前缘（英文版）)

年 卷 期：2016年第7卷第2期

页      面：265-271页

核心收录：

学科分类：0709[理学-地质学] 070901[理学-矿物学、岩石学、矿床学] 07[理学] 

基　　金：Council of Scientific and Industrial Research(CSIR) PLANEX program of India Space Research Organization Department of Space(Government of India) CSR-SHORE-PSC-02005 and ISRO projects(GP)for funding  CSIR for providing Emeritus Scientist Fellowship(UC) 

主　　题：Meteorites High pressure X-ray diffraction Mossbauer spectroscopy Eucrites synchrotron radiation Ferrosilite 

摘      要：We report here high-pressure investigations on Piplia Kalan eucrite-a member of HED （Howardite -Eucrite-Diogenite） family from asteroid 4-Vesta based on synchrotron X-ray diffraction （up to 16 GPa） and ^57Fe Mossbauer spectroscopy （up to 8 GPa）. Dominant with anorthite-rich plagioclase, pigeonite-rich pyroxene and clino-ferrosilite, the sample displayed various phase transitions attaining amorphous character at 16 GPa. These phase transitions of individual components could be explained simultaneously through variations in high-pressure XRD patterns and the Mossbauer parameters. Most prominent P21/c to C2/c transition of pigeonite and ferrosilite was exhibited both as sudden variation in Mossbauer parameters and population inversion of Fe^2＋ in M1 and M2 sites between 2.9 and 3.8 GPa and variation in intensity profile in XRD patterns at 3.56 GPa. Anorthite seemed to respond more to such impact than other components in the sample. Complete amorphization in anorthite which occurred at lower pressure of - 12 GPa implied residual stress experienced due to shock impact. The presence of high pressure （monoclinic） phase of pigeonite and ferrosilite at ambient condition in this eucrite sample confirmed earlier suggestions of an early shock event. This report is an attempt to emphasize the role of anorthite in the determination of the residual stress due to impact process in the parent body thus to understand the behavioral differences amongst HED members.