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| GEOLOGICAL CHARACTERISTICS OF THE HYDROTHERMAL VEIN TYPE GOLDCOPPER DEPOSITS IN NINGWU BASIN:A Case Study of Tongjing Gold-Copper Deposit in Jiangsu Province |
| GAO Li-kun, ZOU Zhi-hong, LI Shu-chun, CAI Wei-dong, SUN Xi-hua, QIAN Ling-yu, ZHANG Long-sheng |
| No. 1 Geological Brigade, Jiangsu Bureau of Geology and Mineral Exploration, Nanjing 210041, China |
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Abstract Numerous hydrothermal vein type Au-Cu deposits are distributed in the Ningwu basin. Among them Tongjing Au-Cu deposit is a typical one. The ore bodies are hosted in the composite positions of NNW-trending compressive-shearing faults and ancient volcanic edifices in vein, veinoid and lentiform, with the characteristics of isometric en echelon arrangement. Studies show that Tongjing Au-Cu deposit underwent the early stage of quartz sulfide, mid-stage of quartz sulfide carbonate and late stage of carbonate. The sulfur isotope δ34S of chalcopyrite is 3.63‰, averagely, with 34S/32S of 22.139, suggesting a mantle source. The ore-forming materials of gold and copper are the liquation production in the late period of differentiation and evolution of alkaline basaltic andesitic magma of the Cretaceous Niangniangshan Formation. The ore-forming hydrotherm rose along the compressive-shearing fault structure, and enriched to mineralization in favorable structural spaces. The homogenization temperature of fluid inclusions ranges from 171 to 253℃, with metallogenic depth of 100-400 m. The Tongjing Au-Cu deposit generally belongs to epi-mesothermal filling vein type related to tectono-volcanic activities.
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Received: 05 August 2014
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2015, Vol. 24 
