登录 | 注册 | 中文  | English  | 用时: 0.83s
元数据
高级检索
首页 > 中国极地考察知识库 > 成果信息库 > 已审查 The protoliths to the sillimanite gneisses from the Larsemann Hills and geological implication in their formation

The protoliths to the sillimanite gneisses from the Larsemann Hills and geological implication in their formation

【标题】The protoliths to the sillimanite gneisses from the Larsemann Hills and geological implication in their formation

【Title】The protoliths to the sillimanite gneisses from the Larsemann Hills and geological implication in their formation

【作者】 任留东; 杨崇辉; 王彦斌; 刘平; 赵越

【Author】 Ren Liudong ; Yang Chonghui ; Wang Yanbin ; Liu Ping ; Zhao Yue

【期刊】极地研究

【Journal】

【期刊年份】2009

【卷】20

【期】1

【关键词】 sillimanite gneiss; protolith; aluminum contents; chemical process; Larsemann Hills

【Keywords】 sillimanite gneiss; protolith; aluminum contents; chemical process; Larsemann Hills

【摘要】The source rock from which the sillimanite gneisses derive mainly was the biotite plagioclase gneiss in the Larsemann Hills. It is the deformation-metamorphism process under special pressure and temperature condition, not the original rock compositions,that controls the presence of sillimanite.To a great degree, the sillimanite gneiss was the mixture of the detaining materials of the migrating felsic melt from the bt-plagioclase gneiss that underwent partial melting and the relics when the melt was removed. In In sillimanitization the original rock had been changed substantially in chemical composition. The related metamorphism process severely deviated from the isochemical series, the process was of, therefore, an open system. In addition, the Al 2 O 3 contents of the original rock was an important, but not critical factor for the formation of sillimanite, i. e. , the sillimanite2bearing rock need not be of aluminum rich in composition, and vise contrarily, the aluminum rock may not p roduce sillimanite. The authors of the present paper postulate that the source rock from which the aluminum rich rock derives need not be of aluminum rich, but sillimanitization is generally the Al2O3 increasing process. The aluminum rich sediments such as clay or shale need not correspond directly to sillimanite-rich gneisses. No argillaceous rock present equals to sillimanite2rich gneiss in chemical composition. The protoliths to the sillimanite gneisses from the Larsemann Hills, east Antarctica, and their adjacent area may be pelite, shale greywacke, sub-greywacke, quartz sandstone and quartz-tourmalinite. If correct, the conclusion will be of significant imp lication for the determination of the sillimanite gneiss formation p rocess and the reconstruction of the protolith setting.

【Abstract】The source rock from which the sillimanite gneisses derive mainly was the biotite plagioclase gneiss in the Larsemann Hills. It is the deformation-metamorphism process under special pressure and temperature condition, not the original rock compositions,that controls the presence of sillimanite.To a great degree, the sillimanite gneiss was the mixture of the detaining materials of the migrating felsic melt from the bt-plagioclase gneiss that underwent partial melting and the relics when the melt was removed. In In sillimanitization the original rock had been changed substantially in chemical composition. The related metamorphism process severely deviated from the isochemical series, the process was of, therefore, an open system. In addition, the Al 2 O 3 contents of the original rock was an important, but not critical factor for the formation of sillimanite, i. e. , the sillimanite2bearing rock need not be of aluminum rich in composition, and vise contrarily, the aluminum rock may not p roduce sillimanite. The authors of the present paper postulate that the source rock from which the aluminum rich rock derives need not be of aluminum rich, but sillimanitization is generally the Al2O3 increasing process. The aluminum rich sediments such as clay or shale need not correspond directly to sillimanite-rich gneisses. No argillaceous rock present equals to sillimanite2rich gneiss in chemical composition. The protoliths to the sillimanite gneisses from the Larsemann Hills, east Antarctica, and their adjacent area may be pelite, shale greywacke, sub-greywacke, quartz sandstone and quartz-tourmalinite. If correct, the conclusion will be of significant imp lication for the determination of the sillimanite gneiss formation p rocess and the reconstruction of the protolith setting.

【基金/项目】 南极拉斯曼丘陵深熔过程的研究 ; 极埃默里冰架-格罗夫山综合地质调查与研究 ; Sapphirine in the high-grade quartzofeldspathic gneiss of the Larsemann Hills,East Antarctica

【下载】 PDF(2.7 MB)