LA-ICPMS U-Pb zircon age and molybdenite Re-Os dating of Yaojialing large zinc-gold polymetallic deposit,Tongling, Anhui Province,China
2014; Science Press; Linguagem: Inglês
ISSN
2095-8927
Autores Tópico(s)Geochemistry and Geologic Mapping
ResumoYaojialing zinc-gold polymetallic ore deposit,located in the transitional area between the Tongling uplift region and the Fanchang fault basin,is a recently-discovered large zinc-gold deposit in the Middle-Lower Reaches of Yangtze River. It is the first large zinc-gold deposit in the Tongling uplift region. It has measured reserves of 1. 2Mt of Zn averaging 3. 64%,as well as 50t of Au,and Cu,Pb and Ag as by-products. The orebodies of it have vein to lenticular shapes and commonly locate in the contact zone with Carboniferous-Triassic limestone and Early Cretaceous granodiorite porphyry intrusion or exist inside limestone xenoliths entrapped within the granodiorite porphyry intrusion. Ore minerals in the main orebodies are usually sphalerite,pyrite,galena,chalcopyrite,gold with minor amount of scheelite,bornite,molybdenite,limonite,tetrahedrite,bismuthinite and malachite. Calcite,garnet,quartz,Kfeldspar,fluorite are the major gangue minerals,while sericite,epidote,diopside,wollastonite,kaolinite and apatite are accessory phases. Hydrothermal alteration is commonly associated with the sulfide metallogeny at Yaojialing deposit. Skarnization,silicification, carbonatization,sericitization,clayzation and potassic alteration are well recognized. A closely related granodiorite porphyry has a LAICPMS U-Pb zircon age of 141. 4 ± 1. 7Ma( MSWD = 0. 78,n = 19). Two molybdenite samples yielded Re-Os isotopic model ages of 141. 2 ± 2. 1Ma and 141. 6 ± 2. 7Ma,consistent with the age of the granodiorite porphyry. The Yaojialing deposit formed as a result of hydrothermal processes during the Early Cretaceous and was also part of the large-scale metallogeny of the Tongling uplift region in the Yanshanian Period. It is revealed that there is a favorable prospect for searching zinc-gold deposit in Tongling uplift district.
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