Zircon LA-ICP-MS U-Pb age, petrog-raphy, geochemistry and tectonic implications of the Guluo alkaline gabbroic rock in the Dayaoshan, Guangxi
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摘要: 古罗碱性辉长岩体包括古罗、黄羌冲两个侵入体,主要由辉长岩、石英辉长岩(或石英闪长岩)组成。岩石以富碱、富集大离子亲石元素(LILE)、轻稀土元素(LREE)和高场强元素(HFSE),无 Nb、Ta 异常,是典型的板内钾玄岩。对古罗辉长岩体进行了高精度的 LA-ICP-MS 锆石 U-Pb 定年,获得石英辉长岩的206Pb/238U 加权平均年龄为165.63±0.95 Ma。研究认为古罗碱性辉长岩体形成于中侏罗世,属典型的板内钾玄岩,形成于大陆地壳伸展拉张减薄的构造背景,为燕山期早期华南后造山阶段的地质记录。
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关键词:
- 岩石地球化学 /
- LA-ICP-MS 锆石 U-Pb 年龄 /
- 碱性辉长岩体 /
- 广西大瑶山
Abstract: Guluo alkaline gabbroic magmatic rocks including Guluo and Huangqiangchong intrusive rocks are comprising of gabbro, quartz-gabbro (or quartz-diorite). These rocks are enriched in alkalies, LILE, LREE and HFSE, characteristed by no Nb and Ta anomalies, which indicates belongs to typical intrapate-shoshonite series. Zircon LA-ICP-MS U-Pb dating of Guluo alkaline gabbroic rocks yields the 206Pb/238U age of 165.63±0.95 Ma. The geochronology data suggests that Guluo alkaline gabbroic rocks as typical intrapate-shoshonite series was formed in the Middle Jurassic Period, and indicated that the magma was generated in the tectonic settings of con-tinental crust extension and thinning, which records post-orogenesis event of South China in the Early Yanshan-nian period.-
Key words:
- petrogeochemistry /
- zircon LA-ICP-MS U-Pb ages /
- alkaline gabbroic rock /
- Dayaoshan
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