Exsolution of ilmenite and Cr-Ti magnetite from olivine of garnet-wehrlite
Exsolution of rod-like ilmenite (Ilm) and Cr-Ti magnetite (Mt) have been found in olivine of garnet-wehrlite from the core of Chinese Continental Sciences Drilling (CCSD). Their composition, morphology, crystal structure and their topotaxies with host olivine have been studied in detail by the transmission electron microscopy (TEM) and electron probe microanalysis (EPMA) technique. It shows that rod-like Ilm exsolution reported in this paper has similar characteristic with that of Alpe Arami olivine, while Cr-Ti magnetite exsolution mentioned in this paper has large discrepancy with chromite exsolution in Alpe Arami olivine. These observations suggest that both of the exsolutions found in this paper should be solid solution phases in β-olivine at their first period, then experiencing decomposition of solid solution and therefore forming Ilm and Cr-Ti magnetite exsolution with the pressure decreasing. So, this garnet-wehrlite perhaps had been ever located in mantle transition zone with a minimum depth of 300 km.
作 者： LIU Xiangwen JIN Zhenmin QU Jing WANG Lu 作者单位： LIU Xiangwen(State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Wuhan 430074, China;Graduate School of China University of Geosciences, Wuhan 430074, China)JIN Zhenmin(State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Wuhan 430074, China;Faculty of Earth Sciences, China University of Geosciences, Wuhan 430074, China)
QU Jing,WANG Lu(Graduate School of China University of Geosciences, Wuhan 430074, China)
刊 名： 中国科学D辑(英文版) SCI 英文刊名： SCIENCE IN CHINA (EARTH SCIENCES) 年，卷(期)： 2005 48(9) 分类号： P3 关键词： garnet-wehrlite ilmenite magnetite exsolution CCSD