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DOI	10.1029/2004JB003330
	Nyainqentanglha Shan: A window into the tectonic, thermal, and geochemical evolution of the Lhasa block, southern Tibet
	Kapp, JLD; Harrison, TM; Kapp, P; Grove, M; Lovera, OM; Lin, D
发表日期	2005
ISSN	2169-9313
EISSN	2169-9356
卷号	110 期号:B8
英文摘要	In the Nyainqentanglha (NQTL) massif, southern Tibet, a late Cenozoic, SE dipping, normal fault exhumed an oblique section of crust in its footwall. U-Th-Pb dating of zircon and monazite from footwall exposures reveals a collage of felsic intrusions including Cretaceous-early Tertiary and Miocene granitoids. Ages of the latter span >10 m. y., suggesting semicontinuous or episodic Miocene magmatism. Geochemical and isotopic analyses show a Gangdese arc affinity, indicating significant mantle heat and mass transfer in their formation and semicontinuous calc-alkaline magmatism throughout the Cenozoic Indo-Asian collision. The undeformed nature of the footwall Cretaceous and Miocene granitoids suggests that Mesozoic-Cenozoic Lhasa block deformation was thin-skinned,'' being concentrated in supracrustal assemblages. This, coupled with the lack of migmatites exposed in the NQTL, implies the exposed crust was not a partial melt zone nor involved in large-scale channel flow. Some Ar-40/Ar-39 thermochronologic studies of footwall K-feldspars reveal that samples collected within several kilometers below the normal fault cooled prior to emplacement of young leucogranites, indicating little perturbation of the background thermal structure since similar to 15 Ma. This plus high melting temperatures and the lack of penetrative granitoid deformation requires that the melts formed at lower crustal levels and were emplaced rapidly to the midcrust. Seismic reflection results showing high bright spot'' anomalies in the midcrust along the NQTL rift may have imaged the youngest magmatic episode or its associated hydrothermal system.
关键词	EAST-WEST EXTENSION MANTLE BENEATH TIBET FOLD-THRUST BELT VOLCANIC-ROCKS LOWER CRUST CONTINENTAL SUBDUCTION QUATERNARY EXTENSION ACTIVE TECTONICS GANGDESE THRUST DULUTH COMPLEX
语种	英语
WOS研究方向	Geochemistry & Geophysics
WOS类目	Geochemistry & Geophysics
WOS记录号	WOS:000231728600002
来源期刊	JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
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/257391
推荐引用方式 GB/T 7714	Kapp, JLD,Harrison, TM,Kapp, P,et al. Nyainqentanglha Shan: A window into the tectonic, thermal, and geochemical evolution of the Lhasa block, southern Tibet[J]. 中国科学院青藏高原研究所,2005,110(B8).
APA	Kapp, JLD,Harrison, TM,Kapp, P,Grove, M,Lovera, OM,&Lin, D.(2005).Nyainqentanglha Shan: A window into the tectonic, thermal, and geochemical evolution of the Lhasa block, southern Tibet.JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH,110(B8).
MLA	Kapp, JLD,et al."Nyainqentanglha Shan: A window into the tectonic, thermal, and geochemical evolution of the Lhasa block, southern Tibet".JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH 110.B8(2005).