江西崇义淘锡坑钨矿区煌斑岩LA-ICP-MS锆石U-Pb同位素定年及地质意义

发布时间：2018-03-24 13:07

本文选题：煌斑岩　切入点：岩石地球化学　出处：《地学前缘》2017年05期

【摘要】：淘锡坑钨矿床是赣南崇(义)-(大)余-(上)犹钨锡多金属成矿带上重要的石英脉型钨矿床,深部存在与成矿关系密切的燕山期花岗岩体。本次研究在详细野外调查和岩相学研究基础上,首次在淘锡坑钨矿区发现煌斑岩脉,岩石定名为闪辉正煌岩,属于钙碱性钾质低钛煌斑岩,地球化学特征显示强烈亏损Nb、Ta、Zr、Hf、Ti等高场强元素,相对富集Rb、Ba、Sr、Pb等大离子亲石元素和高场强元素LREE的特征。利用LAICP-MS锆石U-Pb同位素定年,获得两组年龄,223.3~228.5 Ma可能代表了煌斑岩浆中所捕获锆石的年龄,说明区内存在印支期岩浆活动;158.2~159.6 Ma为煌斑岩脉的侵入年龄。该煌斑岩的侵位是与燕山期(170~150 Ma)南岭地区岩石圈发生全面伸展-减薄,大规模陆壳重熔型花岗岩类产出相伴随,记录了本区存在印支期和燕山期两期岩浆活动,是南岭中生代大规模岩浆活动同一构造背景下的产物。
[Abstract]:The Taoxikeng tungsten deposit is an important quartz vein type tungsten deposit in the Tungsten and tin polymetallic metallogenic belt in southern Jiangxi. On the basis of detailed field investigation and petrographic study, the lamprophyre vein was first discovered in the Tungsten ore area of Taoxikeng, which is named as diorite orthosamarite, in the depth of Yanshanian granitic body, which is closely related to mineralization. It belongs to calc-alkaline potash low-titanium lamprophyre, and its geochemical characteristics show that it is strongly depleted of high field strength elements such as NB ~ (2 +) ~ (2 +) ~ (2 +) ~ (2 +) ~ (2 +), LREE, etc., and it is relatively rich in large ion lithophile elements such as RB _ (b) Ba ~ (2 +) Sr ~ (2 +) Pb and high field strength element (LREE). Two sets of ages (223.3 ~ 228.5 Ma) may represent the ages of zircon trapped in lamprophyre magma. It is suggested that the Indosinian magmatic activity of 158.2 ~ 159.6 Ma is the intrusive age of the lamprophyre vein. The emplacement of the lamprophyre is associated with the comprehensive extension and thinning of the lithosphere in the Nanling area of the Yanshanian period, and the occurrence of large-scale continental crust-remelting type granitoids. The magmatic activities of Indosinian and Yanshanian periods are recorded in this area, which are the products of the same tectonic setting of the Mesozoic large-scale magmatic activities in Nanling.
【作者单位】：长安大学地球科学与资源学院;长安大学西部矿产资源与地质工程教育部重点实验室;陕西中核资源有限公司;中国地质科学院矿产资源研究所;桂林理工大学地球科学学院;
【基金】：国土资源部公益性行业科研专项“南岭东段九龙脑矿田成矿规律与深部找矿示范”(201411050) 国家重点研发计划课题(2016YFC0600208) 国家自然科学基金重点资助计划(41430314);国家自然科学基金项目(41372092) 2017年长安大学“优秀博士学位论文培育资助项目”
【分类号】：P597.3;P618.67

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