气候变化领域集成服务门户(CCPortal): Early Miocene leucogranites in Dinggye area, southern Tibet: Formation mechanism and tectonic implications

CCPortal

	Early Miocene leucogranites in Dinggye area, southern Tibet: Formation mechanism and tectonic implications
	Yu JunJie; Zeng LingSen; Liu Jing; Gao LiE; Xie KeJia
通讯作者	Yu, JJ (通讯作者)
发表日期	2011
ISSN	1000-0569
EISSN	2095-8927
起始页码	1961
结束页码	1972
卷号	27 期号:7
英文摘要	The Ama Drime Massif, Dinggye area, is located in the central Greater Himalaya and consists of granitic gneisses, metapelites, metabasites and massive leucogranites, and has experienced amphibolite- to granulite-facies metamorphism. Whole-rock major- and trace-element, radiogenic isotope (Sr and Nd), and SHRIMP zircon analyses were undertaken to investigate the petrogenic relationship between the leucogranites and the metamorphic rocks, as well as the formation mechanism of the leucogranites. Bulk element and Sr-Nd isotope analyses show that the leucogranites have (1) high SiO2 (> 72%), Al2O3 (> 12%), and A/CNK (> 1.0); (2) high Rb and low Sr, thus high Rb/Sr ratios (> 1.0); (3) high contents of total REE, and substantial negative Eu anomalies; and (4) high initial Sr (Sr-87/Sr-86 (t) = 0.7621 similar to 0.8845) and low Nd (epsilon(Nd)(t) = -13.0 similar to -20.2) isotopic compositions. High Rb/Sr ratios and Sr-Nd isotope systematics indicate that the leucogranites were mainly derived from muscovite dehydration melting of metapelite with a substantial contribution from granitic gneiss. SHRIMP zircon U-Pb dating indicates that the leucogranites have preserved a record of two episodes of partial melting at 21.0 +/- 0.7Ma and 15.8 +/- 0.1Ma, respectively; and the granitic gneisses experienced high-grade metamorphism at 22.2 +/- 1.4Ma,similar to the timing of retrograde metamorphism in this area. In conclusion, both granitic and pelitic gneisses have experienced high-grade metamorphism and anatexis. The Miocene anatectic event could be episodic and at least produced leucogranitic melts at 22 similar to 21 Ma and similar to 16Ma, respectively.
关键词	U-PB ZIRCON OROGEN-PARALLEL EXTENSION MOUNT EVEREST REGION YARDOI GNEISS DOME GEOCHEMICAL CONSTRAINTS STRUCTURAL GEOMETRY NORTHWEST HIMALAYA DETACHMENT SYSTEM CRUSTAL ANATEXIS TETHYAN HIMALAYA
英文关键词	Leucogranite; Granitic gneiss; Metpelite; Greater Himalaya; Crustal anatexis
语种	英语
WOS研究方向	Geology
WOS类目	Geology
WOS记录号	WOS:000293800900005
来源期刊	ACTA PETROLOGICA SINICA
来源机构	中国科学院青藏高原研究所
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/257880
推荐引用方式 GB/T 7714	Yu JunJie,Zeng LingSen,Liu Jing,et al. Early Miocene leucogranites in Dinggye area, southern Tibet: Formation mechanism and tectonic implications[J]. 中国科学院青藏高原研究所,2011,27(7).
APA	Yu JunJie,Zeng LingSen,Liu Jing,Gao LiE,&Xie KeJia.(2011).Early Miocene leucogranites in Dinggye area, southern Tibet: Formation mechanism and tectonic implications.ACTA PETROLOGICA SINICA,27(7).
MLA	Yu JunJie,et al."Early Miocene leucogranites in Dinggye area, southern Tibet: Formation mechanism and tectonic implications".ACTA PETROLOGICA SINICA 27.7(2011).