| 龙宇,徐建,明方平,罗沙,方生红.贵州金沙东部晚二叠世龙潭组底部铝土质泥岩中镓的地球化学特征[J].贵州地质,2024,(4):403-409 |
| 贵州金沙东部晚二叠世龙潭组底部铝土质泥岩中镓的地球化学特征 |
| Mudstone of the Late Permian Longtan Formation, East Jinsha, Guizhou |
| 投稿时间：2024-06-11 |
| DOI： |
| 中文关键词: 金沙县东部 晚二叠世 龙潭组 镓 地球化学元素 |
| 英文关键词:East of Jinsha county Late Permian Epoch Longtan formation Gallium Geochemical elements |
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| 中文摘要: |
| 研究区位于贵州金沙县东部，系统的采集研究区范围内各煤矿区钻孔岩芯晚二叠世龙潭组底部铝土质泥岩样品。X射线衍射测试粘土岩矿物组成，主要为粘土矿物、其次为钾长石和黄铁矿。样品中地球化学元素表现为TiO2、Fe2O3、Al2O3、Ni、Th、U、V富集，CaO、MgO、MnO、Na2O、K2O、Sr、Rb、Co、Ba相对亏损；稀土元素标准化分配曲线明显右倾，(La/Yb)N为12441936，具有明显的轻稀土富集特征，δEu为058068，δCe为072087，表现出Eu和Ce的负异常。龙潭组底部铝土质粘土岩与峨眉山玄武岩具有继承性，其物质来源于玄武岩。粘土岩样品中高粘土矿物含量、高成分成熟度及较低的Mg/Ca比值反映了研究区温暖潮湿古气候条件，高Sr/Ba值指示咸水环境，隆升暴露的氧化环境使大部分化学性质活泼的碱金属元素被析出淋失，而化学性质相对稳定的Ga元素则残留原地或运移至近源低洼地带。 |
| 英文摘要: |
| The research area was located in the east of Jinsha County, Guizhou Province. The borehole core samples of Late Permian Longtan Formation bottom aluminaceous mudstone were systematically collected from coal mining areas within the research area. The mineral composition of claystone was determined by X-ray diffraction, which was mainly clay minerals, followed by potassium feldspar and pyrite. The geochemical elements in the sample ware enriched in TiO2, Fe2O3, Al2O3, Ni, Th, U and V, while CaO, MgO, MnO, Na2O, K2O, Sr, Rb, Co and Ba are relatively deficient. The normalized distribution curve of rare earth elements is significantly to the right, and (La/Yb)N was 12.4419.36, showing obvious enrichment characteristics of light rare earth, δEu was 0.580.68, δCe is 0.720.87, showing negative anomalies of Eu and Ce. The aluminaceous clay rocks at the bottom of Longtan Formation ware inherited from Emei Mountain basalt, and their materials come from basalt. The high clay mineral content, high compositional maturity and low Mg/Ca ratio in the clay rock samples reflect the warm and humid paleoclimate conditions in the study area. The high Sr/Ba value indicates the saltwater environment, and the oxidation environment exposed by uplift causes most of the chemically active alkali metal elements to be eluviated. However, Ga elements with relatively stable chemical properties remain in situ or migrate to near-source low-lying areas. |
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