| 刘娇,周洋,郭宏杰,熊昕,李德威.云南建水腊里河超基性岩地质特征及其构造意义[J].贵州地质,2016,33(3):178-186 |
| 云南建水腊里河超基性岩地质特征及其构造意义 |
| Geological Characteristics and the Tectonic Significance of Ultrabasic Rock of Nali River in Jianshui，Yunnan Province |
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| DOI： |
| 中文关键词: 超镁铁岩 锆石U-Pb测年 大火成岩省 热液改造 云南建水 |
| 英文关键词:Ultrabasic rock Zircon U-Pb age Large igneous province Hydrothermal modification Jian Shui |
| 基金项目:中国地质调查局：云南1∶5万龙朋等六幅区域地质调查（项目编号：1212011220400）。 |
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| 中文摘要: |
| 川滇黔等地在二叠世晚期发生峨眉山玄武岩短期内大规模溢流喷发。滇西地区发育的镁铁—超镁铁质岩均被认为是峨眉山大火成岩省的产物，但在滇东地区却一直缺少该类岩石组合的报道。本文在滇东建水地区首次发现了腊里河超基性岩体，通过LA-ICP-MS锆石U-Pb定年分析表明该超基性岩先期形成年龄为（246±5.2）Ma，为晚二叠-早三叠世的产物，后期中侏罗世晚期（169.6±2.0）Ma（MSWD=3.5）发生岩浆活化。该超基性岩Mg#值平均为78.73，稀土元素表现出略微右倾的平坦型特征，Rb、Sr、Ba、Pb等大离子亲石元素相对富集，高场强元素Zr、Hf相对亏损，Ta异常富集。其地化特征表现出富集型地幔源区特征，与峨眉山玄武岩成因关系密切。晚二叠世建水地区由于地幔柱活动形成地表溢流玄武岩，在深部岩浆房由玄武质岩浆结晶分异作用形成超基性侵入岩，到中侏罗世晚期，伴随着华南地区发生多期次构造运动，先前存在于岩浆房中的超镁铁质岩经过后期热液改造活化，沿着断层裂隙侵入地表。 |
| 英文摘要: |
| Emeishan basalts happened mass effusive eruption in the short term late Permian，in Sichuan，Yunnan，Guizhou et al.Ultrabasic rock was considered to be the production of Emeishan large igneous province，Yunnan west.However，there has been lack of report about ultrabasic rock Yunnan east.In this paper，the ultrabasic rock has been discovered for the first time in Jianshui，Yunnan east，Through the analysis of zircon U-Pb age，the ultrabasic rock formed early in（246±5.2）Ma，then it has happened magmatic activation in the late of middle Jurassic （169.6±2.0）Ma（MSWD=3.5）.Mg# average value is 78.73，REE shows flat type characteristics with slightly to the right，LILE（Rb，Sr，Ba，Pb）shows relative enrichment，HFSE（Zr，Hf）shows relative depletion，Ta showes abnormal enrichment.Geochemical features show that the lherzolite has originated from enrichment type mantle source region，closely related with formation of Emeishan basalt.Late Permian the mantle plume activity make the formation of surface overflow basalt，in the deep magma chamber，basaltic magma crystallization differentiation form ultrabasic rock.By the late of middle Jurassic，along with multiphase tectonic activity south China，the early ultramafic rock in the magma chamber go through lately hydrothermal activation，invade into surface along the fault crevice. |
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