Genesis of volcanic-hosted gold deposits in the Sawur gold belt,northern Xinjiang,China:Evidence from REE,stable isotopes,and noble gas isotopes
会议名称：《中国科学院地质与地球物理研究所2007学术年会》
会议日期：2008年
学科分类：070902[理学-地球化学] 0709[理学-地质学] 07[理学]
基 金：supported by the Innovative Project of the Chinese Academy of Sciences(Grant No.KZC3-SW-137) the National 305 Research Scholarship(Grant nos. 2001BA609A-07-08 and -2003 BA612A-19)
关 键 词：REE Isotopes Gold mineralization Sawur gold belt China
摘 要：The Sawur gold belt,the Sawur Mountains,northern Xinjiang,China,is the eastwards extension of the Zarma-Sawur goldcopper belt in *** Kuoerzhenkuola and Buerkesidai gold deposits are the two largest volcanic-hosted gold deposits in this belt,and are spatially associated with Early Carboniferous calc-alkaline volcanic rocks of the Heishantou *** are hosted in a caldera structure consisting of volcanic rocks and subvolcanic rocks,and controlled by a caldera fracture system superimposed by regional *** host rocks are main andesite in the Kuoerzhenkuola deposit,and carbonaceous silty tuff in the Buerkesidai deposit,respectively. Rare earth element(REE) chemistry,stable isotopes(H,O,C,S),radiogenic isotope(Pb),and noble gas isotopes(He and Ar) have been used to discriminate the sources and evolutionary histories of the ore-forming fluid,and to evaluate the genesis in the Kuoerzhenkuola and Buerkesidai volcanic-hosted gold *** ore-forming fluids of the two deposits share the same origin, withδO andδD data indicating that the water of ore fluids was derived from magmatic water,diluted by meteoric waters. He/He and Ar/Ar values suggest that the He in the ore fluids consists of a mixture of mantle He with minor components of meteoric water He.δS values(0.33 to 2.85‰) show that the sulfur isotope composition of the ore fluids is characterized by mantle *** isotope compositions indicate that the majority of the lead in the ore fluids is mantle-derived,with minor lower crust-derived *** rock and pyrite REE data show that the volcanic rocks could have been a fertile source for the metals. The mantle-derived component in the ore-forming fluids from the two deposits decreased,and the meteoric water gradually increased from early to late mineralization *** and oxygen isotopes suggest that late stage mineralization may have been influenced by ***-Ar geochronological data show that mineralization is synchronous or