Genesis of Delong Granite in East Kunlun Orogen and Its Implication on the Evolution of Paleo-Tethys Ocean

被引：2

作者：

Chen J. ^{[1
,2
]}

Leng C. ^{[1
,2
]}

Fu L. ^{[3
]}

Zhao X. ^{[4
]}

Xing H. ^{[1
,2
]}

机构：

[1] State Key Laboratory of Nuclear Resources and Environment, East China University of Technology, Nanchang

[2] School of Earth Sciences, East China University of Technology, Nanchang

[3] Faculty of Earth Resources, China University of Geosciences, Wuhan

[4] Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou

来源：

Diqiu Kexue - Zhongguo Dizhi Daxue Xuebao/Earth Science - Journal of China University of Geosciences | 2024年 / 49卷 / 02期

关键词：

crust remelting; East Kunlun Orogen; geochemistry; granite; Nd-Hf decoupling; ocean-continental conversion; Paleo-Tethys Ocean;

D O I：

10.3799/dqkx.2022.328

中图分类号：

学科分类号：

摘要：

The East Kunlun Orogen is an important part of the Paleo-Tethys domain. The closure time of the Paleo-Tethys Ocean and the reason for decoupling Nd-Hf isotopes of Permian-Triassic magmatic rocks are still controversial. Zircon chronology and whole rock elemental and isotopic analyses have been carried out on the Delong granite in the East Kunlun Orogen. The results show that the Delong granite was emplaced in the Middle Triassic and belong to metaluminous to weakly peraluminous high silica I-type granite, with low Sr/Y and La/Yb ratios, similar to normal island arc magmatic rocks. Isotopic data show enriched Sr-Nd and enriched to depleted zircon Hf isotopic signatures for the Delong granite. These data, together with petrography, indicate that the Delong granite comes from the mixed melting of new and old crust or the remelting of rocks from mixed source areas such as enriched mantle and oceanic plate (mixture of basalt crust and sediments). These special sources contribute to widespread decoupling of εNd(t) and εHf(t) of the Delong granite and even regional contemporaneous intermediate-acid magmatic rocks. Based on the above conclusions and the geological and geochemical characteristics of the rocks regionally, it is inferred that the Paleo-Tethys Ocean was closed at about 240 Ma. © 2024 China University of Geosciences. All rights reserved.

引用

页码：560 / 576

页数：16

共 42 条

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