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林子宗群火山岩是青藏高原规模最大的火山岩带,但对该火山岩与成矿关系的研究较少。文章以斯弄多低硫化浅成低温热液型银铅锌矿床为例,对矿区主要的赋矿火山岩开展了精确的LA-ICP-MS定年和全岩地球化学分析,获得矿区火山岩锆石U-Pb年龄在62~65 Ma之间,这些岩石属于高钾钙碱性-钾玄岩和过铝质岩石系列,相对富集轻稀土元素(∑LREE/∑HREE=3.39~13.21)和大离子亲石元素(LILE,如Rb、K、Sr);亏损重稀土元素(LaN/YbN=3.02~16.47)和高场强元素(HFSE:Nb、Ta、Ti、P),显示出弧火山特征。结合其他研究数据及区域上典型矿床成岩成矿时代特征,作者指出斯弄多低硫化浅成低温热液型矿床的形成与林子宗群火山作用(62~65 Ma)密切相关,是火山作用驱动地热体系的产物,成岩成矿发生在印度-亚洲大陆初始碰撞期的陆缘火山弧背景下。
The Linzizong group volcanic rocks are the largest volcanic belt in the Qinghai-Tibet Plateau, but there is little research on the relation between the volcanic rocks and metallogenesis. In this paper, we take Laidongdu low-sulfide epithermal silver-lead-zinc deposit as an example to conduct accurate LA-ICP-MS dating and whole-rock geochemical analysis of the major ore-forming volcanic rocks in the mining area. -Pb is between 62 and 65 Ma. These rocks belong to the series of high-K calc-alkaline-potash and peraluminous rocks and are relatively rich in LREEs (ΣLREE / ΣHREE = 3.39 ~ 13.21) and large ions LILE, such as Rb, K and Sr; loss of heavy rare earth elements (LaN / YbN = 3.02 ~ 16.47) and high field strength elements (HFSE: Nb, Ta, Ti and P) Combined with other research data and characteristics of diagenetic and mineralization age of typical deposits in the area, the authors point out that the formation of the Sidong multi-sulfide epithermal deposits is closely related to the Linzizong Group volcano (62-65 Ma) and is driven by volcanism Geothermal products, diagenesis and mineralization occurred in the Indian - Asian continent during the initial collision of the continental margin volcanic arc background.