广西新路—水岩坝钨锡矿田的成因探讨  

A genetic study of Xinlu-Shuiyanba W-Sn orefield, northeast Guangxi

作　　者：顾晟彦[1] 华仁民[1] 戚华文[1] 

机构地区：[1]南京大学成矿作用研究国家重点实验室花岗岩火山岩及成矿理论研究所,江苏南京210093

出　　处：《矿床地质》2007年第3期265-276,共12页Mineral Deposits

基　　金：国家自然科学基金项目(40572057);国家重点基础研究发展规划项目(1999CB403209)的联合资助

摘　　要：广西新路—水岩坝钨锡矿田位于广西平桂地区、燕山中期姑婆山花岗岩的西南接触带,为南岭钨锡多金属成矿带的重要组成部分。文章在前人成果基础上,进行了岩石地球化学、石英流体包裹体成分及Rb-Sr同位素定年等研究,结果表明,该区成矿作用(约151Ma)与姑婆山花岗岩主体(161～165Ma)存在较大的年龄差,因此没有直接的成因联系。姑婆山花岗岩形成后,由于进一步的断裂活动和幔源物质上升在姑婆山南缘形成了晚期花岗质小岩体,伴随的深源流体活动造成了W、Sn等成矿物质的活化、运移和富集,才形成了以六合坳、烂头山为代表的矿床。矿床受晚期成矿花岗岩、有利赋矿层位及断裂构造等因素的综合控制,成矿物质主要来源于花岗岩。激光拉曼探针分析显示,该区矿床流体包裹体的成分主要为CO2、CH4和H2O,结合其他特征,显示可能有较多幔源成分参与,其中新路六合坳矿床流体包裹体极富CH4,而水岩坝烂头山矿床流体包裹体富CO2,反映了两者在流体来源、形成机制、成矿深度等方面的差异。Situated at the southwestern outer contact zone of the Middle Yanshanian Guposhan granite pluton in Pinggui area of Guangxi, the Xinlu-Shuiyanba W-Sn deposit is one of the representative W-Sn-polymetallic orefields in the Nanling Range, South China. Based on the data obtained from previous researches, this paper has studied systematically petrochemistry, Rb-Sr isotopic age dating and fluid inclusion compositions of the quartz, and the results show that the ages of the ore deposits are about 136 Ma, quite different from the age of the host granite of Guposhan, which was dated at （161-165） Ma. It is thus considered that there is no direct relationship between the granite emplacement and the ore formation. There occurred an intrusion of a late small granite body at about 151Ma in the southern part of Guposhan granite pluton, which was probably caused by the further rupture of the crust and the upwelling of mantle material. The activity of associated mantle-derived fluids stimulated the mobilization, transportation and enrichment of W, Sn and other ore-forming elements and resulted in the formation of the Liuheao and Lantoushan ore deposits as representative ones. It is suggested that the ore deposits are controlled by late granite as well as favorable strata and structures, and the ore materials were mainly derived from late granite. Researches on oxygen, hydrogen and sulfur isotopes show that δ^18O values are 8.19‰-13.389‰ and 10.2‰-12.35‰ for Liuheao and Lantoushan ore deposits, respectively, and δ^34S values are 2.09‰-1.7‰ and 0.95‰- 3.6‰, respectively, indicating that ore-forming elements were dominantly derived from the granite. Laser Raman microprobe analyses show that CO2, CH4 and H2O constitute the dominant part of the fluid inclusions in these ore deposits. Combined with other characteristics, it is suggested that oreforming fluids were dominantly derived from the mantle. In addition, the fluid inclusions in the Liuheao ore deposit have rich CH4, while those of the Lantoushan ore depo

关 键 词：地质学 钨锡矿田 成矿流体 矿床成因 新路—水岩坝 广西 

分 类 号：P618.67[天文地球—矿床学] P618.44[天文地球—地质学]