Petrogenesis and tectonic implications of the Mangya A type alkali-feldspar granites in the South Altun, Northwest China

被引：0
|
作者：
Xu N. [1 ]
Wu C. [1 ]
Zheng K. [1 ]
Gao D. [1 ]
机构：
[1] State Key Laboratory of Continental Tectonics and Dynamics, Institute of Geology, Chinese Academy of Geological Sciences, Beijing
来源：
Dizhi Xuebao/Acta Geologica Sinica | 2020年 / 94卷 / 05期
关键词：
A-type granites; LA-ICP-MS U-Pb chronology; Lu-Hf isotopic analyses; Mangya; South Altun orogenic belt;
D O I：
10.19762/j.cnki.dizhixuebao.2020146
中图分类号：
学科分类号：
摘要：
The south Altun Orogenic Belt, which is an important continental subduction-collision orogen belt, lies between the Qaidam basin and Qilian-Kunlun Orogenic Belt, and a number of early Paleozoic granites containing key information about the tectonic evolution of the orogenic belt have been discovered in this belt. The Mangya alkali-feldspar granites are ideal for research on the timing of the post-orogenic extensional environment and the crust mantle interaction; its genetic type, material source and tectonic environment need detailed study. In this paper, we present results of geochemical, LA-ICP-MS U-Pb and Lu-Hf isotopic analyses on the Mangya alkali-feldspar granites and discuss their tectonic implications. The samples are high in SiO2, iron, alkali, poor in calcium and magnesium, and depleted in Ba, Sr, P, Eu and Ti, belonging to A2-type granites; the granites were generated 403~424 Ma, and were product of partial melting of the Meso-Neoproterozoic juvenile crust materials (juvenile quartz-feldspathic materials or calc-alkaline granitoids). The magma source might have contained a small amount of Ca-rich plagioclase residuals. After 424 Ma, the South Altun was in post-orogenic extensional environment, and upwelling of the mantle materials was triggered by the isostatic adjustment between blocks, causing the partial melting of the crust materials which formed the A-type granites. © 2020, Science Press. All right reserved.
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页码：1431 / 1449
页数：18
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