东昆仑哈日扎铅锌多金属矿区英云闪长岩锆石U-Pb定年、地球化学及其地质意义

发布时间：2018-04-26 06:20

本文选题：锆石U-Pb定年 + 地球化学　；参考：《地质科技情报》2016年05期

【摘要】：东昆仑哈日扎铅锌多金属矿区地处东昆仑造山带东段,属青海都兰县境内,是近年来新发现的一处具有良好前景的铅锌多金属矿勘查区。矿体赋存于英云闪长岩中,与其具有密切的成矿关系。利用LA-ICP-MS锆石U-Pb测年技术,获得英云闪长岩加权平均年龄为(422.3±1.9)Ma(n=26,MSWD=0.42),确定其形成时代为晚志留世,属加里东晚期。这也是该区首次发现与成矿密切相关的加里东晚期岩体。岩石地球化学研究表明,该英云闪长岩为强过铝质高钾钙碱性系列岩石;明显表现为富集Rb、K等大离子亲石元素、LREE和活泼的不相容元素(U、Th),相对亏损Nb、Ta、P、Ti等高场强元素和Sr元素,显示了轻稀土元素强烈富集的右倾式稀土元素配分型式,具较明显的负Eu异常。岩石物质来源具有壳幔混熔的特点。综合东昆仑区域地质构造演化特征,认为哈日扎英云闪长岩可能形成于后碰撞构造阶段,为东昆仑造山带早古生代构造旋回的产物。
[Abstract]:The Hareza Pb-Zn polymetallic ore area in East Kunlun is located in the eastern part of the East Kunlun orogenic belt and belongs to Dulan County in Qinghai Province. It is a promising prospecting area for the Pb-Zn polymetallic deposits discovered in recent years. The orebody occurs in Yingyun diorite and has a close metallogenic relationship. Using LA-ICP-MS zircon U-Pb dating technique, the weighted mean age of quartz diorite is 422.3 卤1.9m ~ (26) MSWD ~ (0.42), which is determined to be late Silurian, belonging to the late Caledonian period. This is the first time that the late Caledonian rock mass closely related to mineralization was discovered in this area. The petrogeochemical study shows that the diorite is a strong peraluminous high potassium calc-alkaline series of rocks, which is obviously characterized by enrichment of large ion lithophile elements, such as RbCon K, LREE, and active incompatible elements, such as UTH, and the relative depletion of high field strength elements and Sr elements, such as NbBU TaPnTi, etc. It is shown that the REE distribution pattern with strong enrichment of light rare earth elements (LREE) is of the right-dip REE distribution pattern with obvious negative EU anomalies. The source of rock material is characterized by mixing of crust and mantle. Based on the characteristics of the regional tectonic evolution in East Kunlun, it is considered that the Haliza diorite may have been formed in the post-collision tectonic stage and was the product of the early Paleozoic tectonic cycle in the East Kunlun orogenic belt.
【作者单位】：中国地质调查局西安地质调查中心;长安大学;青海省第三地质矿产勘查院;
【基金】：中国地质调查局项目(DD20160013) 西北整装勘查跟踪综合与动态评估(1212011220861) 青海省都兰县察汗乌苏河地区1∶5万地质矿产综合调查(12120115022101)
【分类号】：P597.3;P618.2

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