气候变化领域集成服务门户(CCPortal): Origin of middle Miocene leucogranites and rhyolites on the Tibetan Plateau: Constraints on the timing of crustal thickening and uplift of its northern boundary

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DOI	10.1007/s11434-011-4813-4
	Origin of middle Miocene leucogranites and rhyolites on the Tibetan Plateau: Constraints on the timing of crustal thickening and uplift of its northern boundary
	Zhang LiYun; Ding Lin; Yang Di; Xu Qiang; Cai FuLong; Liu DeLiang
通讯作者	Ding, L (通讯作者)
发表日期	2012
ISSN	1001-6538
EISSN	1861-9541
起始页码	511
结束页码	524
卷号	57 期号:5
英文摘要	Leucogranites play a significant role in understanding crustal thickening, melting within continental collisional belts, and plateau uplift. Field investigations show that Miocene igneous rocks from the Hoh Xil Lake area mainly consist of two-mica leucogranites and rhyolites. We studied the Bukadaban two-mica leucogranites and the Kekao Lake, Malanshan and Hudongliang rhyolites by zircon U-Pb, muscovite and sanidine Ar-40/Ar-39 geochronology, and whole-rock geochemical and Sr-Nd isotopic analysis. Results yielded crystallization and cooling ages for the Bukadaban leucogranites of 9.7 +/- 0.2 and 6.88 +/- 0.19 Ma, respectively. Extrusive ages of the Kekao Lake and Malanshan rhyolites are 14.5 +/- 0.8 and 9.37 +/- 0.30 Ma, respectively. All rocks are enriched in SiO2 (70.99%-73.59%), Al2O3 (14.39%-15.25%) and K2O (3.78%-5.50%) but depleted in Fe2O3 (0.58%-1.56%), MgO (0.11%-0.44%) and CaO (0.59%-1.19%). The rocks are strongly peraluminous (A/CNK=1.11-1.21) S-type granites characterized by negative Eu anomalies (delta Eu=0.18-0.39). In also considering their Sr-Nd isotopic compositions (Sr-87/(86)Sri=0.7124 to 0.7143; epsilon Nd (9 Ma)=-5.5 to -7.1), we propose that these igneous rocks were generated through dehydration melting of muscovite in the thickened middle or lower crust of northern Tibet. Melting was probably triggered by localized E-W stretching decompression in the horse tails of Kunlun sinistral strike-slip faults. Reactivation of the Kunlun strike-slip faults, accompanied by emplacement of leucogranite and eruption of rhyolite in the Hoh Xil Lake area, indicates that large-scale crustal shortening and thickening in northern Tibet mainly occurred before 15 Ma. In addition, these findings suggest that the northern Tibetan Plateau attained its present elevation (similar to 5000 m) at least 15 Ma ago.
关键词	INDIA-ASIA COLLISION YARDOI GNEISS DOME ULUGH-MUZTAGH AREA KUNLUN FAULT ZONE SOUTHERN TIBET VOLCANIC-ROCKS GEOCHEMICAL CONSTRAINTS NORTHWESTERN TIBET TETHYAN HIMALAYA AGE
英文关键词	Hoh Xil; zircon U-Pb dating; Ar-40/Ar-39 dating; leucogranite; rhyolite; crustal thickening; Tibetan Plateau uplift
语种	英语
WOS研究方向	Science & Technology - Other Topics
WOS类目	Multidisciplinary Sciences
WOS记录号	WOS:000299924000012
来源期刊	CHINESE SCIENCE BULLETIN
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/257982
推荐引用方式 GB/T 7714	Zhang LiYun,Ding Lin,Yang Di,et al. Origin of middle Miocene leucogranites and rhyolites on the Tibetan Plateau: Constraints on the timing of crustal thickening and uplift of its northern boundary[J]. 中国科学院青藏高原研究所,2012,57(5).
APA	Zhang LiYun,Ding Lin,Yang Di,Xu Qiang,Cai FuLong,&Liu DeLiang.(2012).Origin of middle Miocene leucogranites and rhyolites on the Tibetan Plateau: Constraints on the timing of crustal thickening and uplift of its northern boundary.CHINESE SCIENCE BULLETIN,57(5).
MLA	Zhang LiYun,et al."Origin of middle Miocene leucogranites and rhyolites on the Tibetan Plateau: Constraints on the timing of crustal thickening and uplift of its northern boundary".CHINESE SCIENCE BULLETIN 57.5(2012).