气候变化领域集成服务门户(CCPortal): Discovery of the Zhegucuo Au (As)-bearing fine granular quartz diorite in the eastern Tethyan Himalayan Belt and its significance

CCPortal

	Discovery of the Zhegucuo Au (As)-bearing fine granular quartz diorite in the eastern Tethyan Himalayan Belt and its significance
	Bian, Q. T.; Ding, L.
通讯作者	Bian, QT (通讯作者)
发表日期	2006
ISSN	1000-0569
EISSN	2095-8927
起始页码	977
结束页码	988
卷号	22 期号:4
英文摘要	This paper reports newly discovered An (As)-bearing fine granular high-Mg quartz diorites in the Zhegucuo hydrothermal Sb-Au deposit, in the eastern Tethyan Himalayan Belt. The rocks have been mostly altered and disseminated sulfide mineralized, and intruded in the Upper Triassic-Lower Jurassic black shale as veins or apophyses. Many gabbroid veins and few olivine websterite bodies are distributed in the Zhegucuo area. The geochemical characteristics of the An (As) -bearing fine granular high-Mg quartz diorites are similar to high-Mg adakite, such as SiO2 >= 56%, high Al2O3 content (> 15%), high Mg-# (48 similar to 59), high Cr (75 X 10(-6) similar to 130 x 10(-6)) and Ni content (54 X 10(-6) similar to 74 X 10(-6)), rich in large ion lithophile elements (LILE), relatively depleted in high strength field elements (HFSE) and HREE, (La/Yb)(N) > 12, weakly negative Eu anomaly (delta Eu = 0.81 similar to 0.91), relatively high and variable Sr content(209.28 X 10(-6) similar to 685.14 X 10(-6)), low Y and Yb content, Y < 16 X 10(-6), Yb < 1.7 X 10(-6), flat HREE pattern, (Ho/Yb)(N) approximate to 1, relatively high and variable Sr/Y (14.58 similar to 47.28). The Nd-Sr-Pb isotopic characteristics of the Au(As)-bearing fine granular high-Mg quartz diorites are high I-Sr(0.709726 similar to 0.711203), epsilon(Nd) (t) = -3.08 similar to -1.15, Pb-206/Pb-204 = 18.638 similar to 18.672, Pb-207/Pb-204 = 15.694 similar to 15.702, Pb-208/Pb-204 = 38.983 similar to 39.016. Two K-Ar isotopic ages of 42.54 +/- 0.94Ma and 43.21 +/- 1.14Ma for An (As)-bearing fine granular high-Mg quartz diorites have been obtained. The rocks were probably formed by the melting of underplated basaltic lower crust having the same geochemical characteristics as gabbroid occurred in the Zhegocuo area, and source of which was the continental mantle with weakly enriched in EMII matter. In Late Jurassic, a basaltic magma underplating took place in the eastern Tethyan Himalayan Belt. In Eocene (approximate to 43Ma), the thickness of crust in the studied area had been thickened more than 40km due to the collision between India and Asia continents (approximate to 65Ma). A tectonic event induced melting of the underplated basaltic lower crust in that time, by which the magma of An ( As) -bearing fine granular high-Mg quartz diorites was produced. Then the magma moved up and intruded shallow crust, along with the formation of the Au (As) -bearing fine granular high-Mg quartz diorites and the porphyry An (As) deposit. The An (As)-bearing fine granular high-Mg quartz diorites are favorable to An mineralization. It is approximately determined that the rocks contain porphyry-type An (As) mineralized bodies. The discovery indicates that a porphyry-type An (As) mineralized zone probably existed in the eastern Tethyan Himalayan Belt. It is also of significance for understanding tectonics and geodynamics of the Tethyan Himalayan Belt.
关键词	GENESIS EVOLUTION ANDESITES GANGDESE PORPHYRY ORIGIN MAGMAS GROWTH ROCKS GOLD
英文关键词	An(As)-bearing quartz diorite; porphyry An(As) deposit; high-Mg adakite; geochemistry; Tethyan Himalayan Belt
语种	英语
WOS研究方向	Geology
WOS类目	Geology
WOS记录号	WOS:000238367700021
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/257401
推荐引用方式 GB/T 7714	Bian, Q. T.,Ding, L.. Discovery of the Zhegucuo Au (As)-bearing fine granular quartz diorite in the eastern Tethyan Himalayan Belt and its significance[J]. 中国科学院青藏高原研究所,2006,22(4).
APA	Bian, Q. T.,&Ding, L..(2006).Discovery of the Zhegucuo Au (As)-bearing fine granular quartz diorite in the eastern Tethyan Himalayan Belt and its significance.ACTA PETROLOGICA SINICA,22(4).
MLA	Bian, Q. T.,et al."Discovery of the Zhegucuo Au (As)-bearing fine granular quartz diorite in the eastern Tethyan Himalayan Belt and its significance".ACTA PETROLOGICA SINICA 22.4(2006).