| 华北东部橄榄岩岩石化学特征及其岩石圈地幔演化意义 |
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| 引用本文： | 郑建平,路凤香,余淳梅,袁晓萍,张瑞生.华北东部橄榄岩岩石化学特征及其岩石圈地幔演化意义[J].地球科学,2006,31(1):49-56. |
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| 作者姓名： | 郑建平 路凤香 余淳梅 袁晓萍 张瑞生 |
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| 作者单位： | 中国地质大学地质过程与矿产资源国家重点实验室，湖北武汉?430074 |
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| 基金项目： | 国家自然科学基金项目(No．40425002)
长江学者和创新团队发展计划(IRT0441) |
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| 摘 要： | 华北东部古生代以来火山岩中捕虏体橄榄岩和苏鲁早中生代构造侵位橄榄岩的岩石化学结果表明: 古生代金伯利岩侵位时仍然存在的难熔、漂浮克拉通地幔在中、新生代时其大部被新生饱满的岩石圈地幔物质取代置换.在100 Ma前(但不早于178 Ma), 新生软流圈物质就已开始沿古老岩石圈内的地幔薄弱带和岩石圈深断裂带对克拉通地幔进行侵蚀、交代和混合作用, 引起岩石圈大幅减薄.这一减薄存在时间、空间的不均匀性, 但在老第三纪达最大.新第三纪以来, 上涌的软流圈物质由于温度下降回落(岩石圈小幅增厚)并转化为新生岩石圈地幔, 实现地幔置换过程.分析的苏鲁造山带橄榄岩是早中生代构造侵位改造过的古老岩石圈地幔物质.
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| 关 键 词： | 橄榄岩 岩石化学 地幔置换 华北东部 |
| 文章编号： | 1000-2383（2006）01-0049-08 |
| 收稿时间： | 2005-09-22 |
| 修稿时间： | 2005-09-22 |
Peridotitic Petrochemistry of the Eastern North China: Significance for Lithospheric Mantle Evolution |
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| ZHENG Jian-ping,LU Feng-xiang,YU Chun-mei,YUAN Xiao-ping,ZHANG Rui-sheng.Peridotitic Petrochemistry of the Eastern North China: Significance for Lithospheric Mantle Evolution[J].Earth Science-Journal of China University of Geosciences,2006,31(1):49-56. |
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| Authors: | ZHENG Jian-ping LU Feng-xiang YU Chun-mei YUAN Xiao-ping ZHANG Rui-sheng |
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| Institution: | State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Wuhan 430074, China |
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| Abstract: | A petrochemical analysis was undertaken of peridotitic xenoliths in volcanic rocks that erupted from the Paleozoic to the Cenozoic within the eastern part of the North China craton, and the peridotites as tectonic intrusive in the Early Meso-zoic from the Sulu orogen. The results show that the cratonic mantle, which was refractory and existed when the kimberlites intruded in the Paleozoic, had almost been replaced by the newly accreted fertile lithospheric mantle during the Mesozoic-Ce-nozoic. The erosion, metasomatism and intermingling caused by the accreted asthenospheric material acting on the craton mantle along the weak zone and deep fault (such as the Tanlu fault) in the existing lithosphere resulted in the lithosphere thinning at a larger scale 100 Ma ago (but later than 178 Ma). The largest thinning would be in the Eogene. The upwelling asthenospheric material transformed into accreted lithospheric mantle due to the asthenospheric temperature falling in the Neogene (leading to relatively slight lithospheric incrassation), and finally accomplished mantle replacement. The peridotitic body in the Sulu orogen represents the products spread from the modified cratonic lithospheric mantle. |
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| Keywords: | peridotite petrochemistry mantle replacement eastern North China |
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