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。
Taoxikeng is one of the most important quartz-vein-type of tungsten deposit in Chong-Yu-You tungsten-tin polymetallic metallogenie belt and the Yanshanian granite which is hidden beneath the deposit has a close relationship with the tungsten-tin polymetallic mineralization. Based on the field and petrographic research, lamprophyre is first discovered in the Taoxikeng, which belongs to potassic calc-alkaline series, with alkali-rich, high K and low Ti features. Geochemically, the rocks show relatively depletion in HFSE （Nb, Ta, Zr, Hf, Ti） and enrichment in LILE （Rh, Ba, Sr, Pb） and LREE. LA-ICP-MS U-Pb zircon ages for the lamprophyre are 223. 3 ± 2. 8 Ma and 158. 2 q- 3. 1 Ma, indicating the age of the captured zircons and the emplacement age of the lamprophyre respectively. The two ages imply that two stages of magmatic activity which were Indosinian and Yanshanian magmatism existed in Taoxikeng tungsten deposit and the lamprophyre formed in the Late Jurassic. The lamprophyre was the product of the intensive Mesozoic magmatism in Nanling region. The fact that a few intermediate to mafic dykes went with the intensive crust remelting type of granite in Yanshanian indicates that comprehensive lithospheric extension and thinning occurred in Nanling region at that time.
出处
《地学前缘》
EI
CAS
CSCD
北大核心
2017年第5期93-108,共16页
Earth Science Frontiers
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"
关键词
煌斑岩
岩石地球化学
锆石U-PB测年
淘锡坑钨矿
lamprophyre
petrogeochemistry
zircon LA-ICP-MS U-Pb dating
Taoxikeng tungsten deposit
