Petrogenesis of Acidic Volcanic Rocks in Sangxiu Formation, East-Central Segment of Tethyan-Himalaya: Response to Break-up of Eastern Gondwana Continent?

被引：0
|
作者：
Tian J. [1 ]
Ding F. [2 ]
Hao S. [1 ]
Pei X. [1 ]
Li T. [1 ]
Sun Y. [2 ]
Xie X. [3 ]
机构：
[1] State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology, Chengdu
[2] College of Earth Sciences, Chengdu University of Technology, Chengdu
[3] School of Earth System Science, Tianjin University, Tianjin
来源：
Diqiu Kexue - Zhongguo Dizhi Daxue Xuebao/Earth Science - Journal of China University of Geosciences | 2021年 / 46卷 / 11期
关键词：
Acid volcanic rock; East Gondwana; East⁃central segment of Tethyan⁃Himalaya; Petrogenesis; Petrology; Sangxiu Formation;
D O I：
10.3799/dqkx.2021.363
中图分类号：
学科分类号：
摘要：
For a long time, there have been many controversies on whether the acid volcanic rocks of Sangxiu Formation in the central and eastern parts of the Tethyan-Himalaya tectonic belt were formed by crustal anatism and were related to the break-up of East Gondwana continent. In this study, the characteristics of acid volcanic rocks of Sangxiu Formation in YamzhoYumco area were studied. Based on the detailed field geological survey and sample collection, the petrography characteristics, LA-ICP-MS zircon U-Pb geochronology, whole-rock geochemistry and Hf isotope of zircon were investigated. The results show that weighted mean age of the two acid volcanic rock samples (RYA01 and DYA01) at the bottom of Sangxiu Formation in YamzhoYumco area were 139.1±1.3 Ma (1σ, MSWD=1.08) and 137.3±1.4 Ma (1σ, MSWD=0.98), respectively, indicating that the two acid volcanic rock samples were formed by the Early Cretaceous volcanic activity in the Tethyan-Himalaya region. The geochemical and Hf isotopic geochemical characteristics show that the acidic volcanic rocks have high content of SiO2, low magnesium index, high A/CNK ratio, enrichment of Al, LREE and Th, and strong depletion of Nb. The zircon εHf(t) values range from -20.1 to -10.5, with an average of -13.5. It is revealed that the acid volcanic rocks of Sangxiu Formation in YamzhoYumco area are magmatic products of partial melting of overlying crust induced by mantle derived magma underplating in the northern margin of Indian continent. Combining with the previous study, it is recognized that the genesis of the acid volcanic rocks is related to the rifting of East Gondwana continent. It is the early product of Kerguelen mantle plume. © 2021, Editorial Department of Earth Science. All right reserved.
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页码：3926 / 3944
页数：18
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