Geology of the post-collisional porphyry copper-molybdenum deposit at Qulong, Tibet

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	Geology of the post-collisional porphyry copper-molybdenum deposit at Qulong, Tibet
	Yang, ZM (Yang, Zhiming); Hou, ZQ (Hou, Zengqian); White, NC (White, Noel C.); Chang, ZS (Chang, Zhaoshan); Li, ZQ (Li, Zhenqing); Song, YC (Song, Yucai)
刊名	ORE GEOLOGY REVIEWS
	2009
卷号	36 期号:1-3 页码:133-159
关键词	Porphyry copper-molybdenum deposits Geology Post-collisional Qulong Tibet
ISSN号	0169-1368
英文摘要	Porphyry deposits are usually thought to form from subduction-related calc-alkaline magmas in magmatic arc settings, although some porphyry deposits also occur in post-collisional extensional settings. The post-collisional deposits remain poorly understood. Here we describe the igneous geology, alteration mineralogy and mineralization history of Qulong, a newly-discovered porphyry Cu-Mo deposit in southern Tibet that belongs to the post-collisional class. The deposit is associated with Miocene monzogranite-granodiorite intrusions and is hosted partly by Jurassic andesitic-clacitic volcanic rocks. The deposit contains 7.1 Mt Cu and 0.5 Mt Mo metal. The similar to 19.5 Ma granodioritic-monzogranitic Rongmucuola pluton with diorite enclaves is the earliest Miocene intrusive unit. It was intruded by a regularly-shaped stock (P porphyry) and then thin dikes (X porphyry) of monzogranite at about 17.7 Ma. The main Cu-Mo mineralization is associated with the P porphyry. A barren diorite porphyry intruded the P and X porphyries around 15.7 Ma. Petrologic trends of the intrusions suggest that the Miocene intrusions have similar origins and probably formed by fractionation of a deeper magma chamber. Emplacement of Miocene porphyries, controlled by the QuIong anticline, is in direct response to the rapid uplift/erosion of the Gangdese arc batholiths in southern Tibet. Miarolitic cavities and unidirectional solidification textures, key evidence for volatile separation, have been recognized in the P and X porphyries, respectively. Early potassic alteration, characterized by quartz-K feldspar (+/-anhydrite), pervades the P porphyry and Rongmucuola pluton. Laterally, this alteration grades into quartz-biotite-anhydrite (+/-K feldspar), which affects all Miocene intrusions except the latest dioritic porphyry. Wall rocks of Rongmucuola pluton and Jurassic andesitic-clacitic volcanics within 1-1.5 km of the porphyries are dominated by pervasive potassic alteration. An outer halo of propylitic alteration (epiclote-chlorite+/-calcite) extends up to 2 km away from the deposit. Feldspar-destructive alteration (sericite-chlorite+/-clay minerals) has overprinted most of the potassic and part of the propylitic alteration. The alteration is strongly pervasive in the interior of the porphyry bodies and occurs as vein halos away from the porphyry bodies. The earliest quartz-K feldspar alteration and veins are barren, whereas approximately 60% of the Cu reserves is associated with slightly later quartz-biotite-anhydrite alteration. Barren assemblages are related to irregular quartz (-K feldspar+/-anhydrite) veins, which are truncated by the X porphyry. Cu sulfide-bearing assemblages are associated with discontinuous chalcopyrite (+/-biotite) and continuous quartz-anhydrite-chalcopyrite (+/-molybdenite) veins. Deposition of Cu-Mo with abundant anhydrite occurred during or between emplacement of closely related porphyries from high temperature magmatically-derived fluids, and was probably caused by the disproportionation of SO(2). (C) 2009 Elsevier B.V. All rights reserved.
学科主题	矿床地质
WOS关键词	EAST-WEST EXTENSION ; NEW-SOUTH-WALES ; CU-AU DEPOSIT ; VOLCANIC-ROCKS ; GOLD DEPOSITS ; ORE-DEPOSITS ; EVOLUTION ; BEARING ; PLATEAU ; ORIGIN
WOS研究方向	Geology ; Mining & Mineral Processing
语种	英语
出版者	ELSEVIER SCIENCE BV
WOS记录号	WOS:000271411200008
内容类型	期刊论文
源URL	[http://119.78.100.197/handle/2HKVOGP0/39044]
专题	中国地质调查局
作者单位	Chinese Acad Geol Sci, Inst Mineral Resources, Beijing 100037, Peoples R China
推荐引用方式 GB/T 7714	Yang, ZM ,Hou, ZQ ,White, NC ,et al. Geology of the post-collisional porphyry copper-molybdenum deposit at Qulong, Tibet[J]. ORE GEOLOGY REVIEWS,2009,36(1-3):133-159.
APA	Yang, ZM ,Hou, ZQ ,White, NC ,Chang, ZS ,Li, ZQ ,&Song, YC .(2009).Geology of the post-collisional porphyry copper-molybdenum deposit at Qulong, Tibet.ORE GEOLOGY REVIEWS,36(1-3),133-159.
MLA	Yang, ZM ,et al."Geology of the post-collisional porphyry copper-molybdenum deposit at Qulong, Tibet".ORE GEOLOGY REVIEWS 36.1-3(2009):133-159.