大别超高压变质过程中部分熔融作用的地球化学约束

凌文黎; 张宏飞; 高山; 钟增球; 韩吟文; 徐启东

Volume 25 Issue 6

Jun. 2000

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Article Navigation > Earth Science > 2000 > 25(6): 573-578

Ling Wenli, Zhang Hongfei, Gao Shan, Zhong Zengqiu, Han Yinwen, Xu Qidong, 2000. GEOCHEMICAL CONSTRAINTS ON THE PARTIAL MELTING OF DABIE SUBDUCTED BLOCKS DURING UHPM PROCESS. Earth Science, 25(6): 573-578.

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Ling Wenli, Zhang Hongfei, Gao Shan, Zhong Zengqiu, Han Yinwen, Xu Qidong, 2000. GEOCHEMICAL CONSTRAINTS ON THE PARTIAL MELTING OF DABIE SUBDUCTED BLOCKS DURING UHPM PROCESS. Earth Science, 25(6): 573-578.

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GEOCHEMICAL CONSTRAINTS ON THE PARTIAL MELTING OF DABIE SUBDUCTED BLOCKS DURING UHPM PROCESS

Faculty of Earth Sciences, China University of Geosciences, Wuhan 430074, China

Received Date: 2000-05-09
Publish Date: 2000-11-25

Abstract

Abstract

This paper presents a comprehensive geochemical study of rocks from the cross section of Sidaohe quarry in Macheng, one of the representative outcrops of eclogite and its host rocks in Dabie UHPM belt. It is revealed in this paper that the eclogite shares the geochemical features with N MORB, and its felsic host rocks can be categorized as TTG gneiss and garnet bearing granite. Evidences from REE and w (Nb) / w (Ta) ratios, Sm Nd isotopes and U Pb zircon dating favor the scenario that TTG gneiss originated from the partial melting of eclogite during the process of subduction, therefore, a special allochthonous relationship in tectonics arises between TTG gneiss and eclogite, the origin of TTG gneiss, while the garnet bearing granite would have resulted from the partial melting of eclogite during its exhumation, but the V type REE pattern denotes that HREE enriched mineral (s) was crystallized when the granite was forming, and the garnet would have been the most favorable candidate of these minerals. Low w (Nb) / w (Ta) ratios of garnet bearing granite indicate that the melting occurred in some extent due to fluid metasomatism, a product of the retrograde metamorphism of UHPM rocks. Therefore, the garnet bearing granite and eclogite would have been in a sub in situ relationship, as the granite may have occurred in the depth where garnet was stable.
- UHPM belt,
- partial melting,
- fluid matasomatism,
- geochemical constraint,
- western Dabie

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References(20)

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