| 深成古岩溶不整合构造系统构造岩相学与金属成矿 |
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| 引用本文： | 方维萱.深成古岩溶不整合构造系统构造岩相学与金属成矿[J].地质学报,2022,96(7):2585-2610. |
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| 作者姓名： | 方维萱 |
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| 作者单位： | 1）有色金属矿产地质调查中心，北京，100012；
2）有色金属矿产地质调查中心，矿山生态环境资源创新实验室，北京，100012 |
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| 基金项目： | 本文为云南省企业基础研究应用基础研究联合专项（编号 202101BC070001-015）、自然资源部公益性行业科研专项项目(编号201511016-1)、国家科技部科技支撑计划课题（编号 2006BAB01 B09)和科技部转制科研院所专项资金项目(编号 2008EG115074)联合资助的成果 |
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| 摘 要： | 古岩溶风化壳和岩溶构造与生态环境资源和地球演化关系密切，对深成的古岩溶构造系统识别属关键科学问题和技术难题。在滇黔桂地区地表水岩溶作用形成了山顶侵蚀面、岩溶侵蚀相系和砖红壤岩溶风化壳；地下水岩溶作用形成了垂向岩溶构造相带、缓倾斜的侧向岩溶构造相带、隐伏岩溶相带及隐伏岩溶前锋面，它们为表生岩溶构造的物质组成。进行大比例尺构造岩相学填图和解析研究认为云南个旧表生岩溶构造系统具有“顶面红土型岩溶风化壳、上部垂向岩溶构造带、中部缓倾斜的侧向岩溶构造带、底部不透水层（花岗岩和变海相火山岩顶面）”4个构造岩相学垂向分带模型，它们继承了先存多期次岩溶作用和岩浆热液岩溶作用。这种垂向分带模式有助于重建深成的古岩溶不整合构造系统。深成的古岩溶不整合构造系统由古气成热水、古火山热水、古火山喷发-岩浆侵位有关的复合热液岩溶作用等叠加在先存岩溶构造系统上形成，发育上覆岩性封闭层，经历了埋藏成岩、热液叠加成岩和层间滑脱构造叠加改造等，具有显著多期次的热流体叠加改造和再造作用。深成古岩溶不整合构造系统属重要油气储层、（非）金属矿产的储集层。对云南个旧地区中—新生代岩溶构造系统、新疆乌拉根地区古近纪热水岩溶不整合构造系统、贵州大厂地区二叠纪火山热水岩溶不整合构造系统、云南东川地区小溜口岩组（Ar3-Pt1x）顶面火山喷发-岩浆侵入有关的元古宙复合热液岩溶构造系统进行解析研究，揭示4类深成的古岩溶不整合构造系统物质组成和形成机制，认为深成的古岩溶不整合构造系统内关键战略矿产成矿潜力巨大。
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| 关 键 词： | 古岩溶 构造岩相学 酸性热液岩溶 叠加成岩相系 古岩溶不整合构造系统 关键战略矿产 |
| 收稿时间： | 2021/3/7 0:00:00 |
| 修稿时间： | 2022/1/4 0:00:00 |
On tectonic lithofacies of hypogene paleokarst unconformable tectonic systems and metallic mineralization |
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| FANG Weixuan.On tectonic lithofacies of hypogene paleokarst unconformable tectonic systems and metallic mineralization[J].Acta Geologica Sinica,2022,96(7):2585-2610. |
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| Authors: | FANG Weixuan |
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| Abstract: | Weathering crust of paleokarst tectonics had close relationships with eco-environment and mineral resources and evolution of the earth. Identification of the system of hypogene paleokarst tectonics is a key scientific issue and a technological puzzle. Erosion surface of peaks, facies system of karst erosion, and lateritic weathering crust in the Yunnan-Guizhou-Guangxi area are being formed by the groundwater. However, the vertical karst lithofacies, the gentle-dipping lateral karst lithofacies, the buried karst lithofacies, and the buried karst-front have been formed by underground water. All of the above mentioned belong to the material compositions of the supergene karst tectonic system. Based on the tectonic lithofacies mapping and analyses on a large-scale in the Gejiu Sn-Cu-W-Cs-Rb-polymetals ore-concentrated area, Yunnan province, the material compositions of the supergene karst tectonic system comprise four vertical zones of tectonic lithofacies. These are the lateritic weathering crust at the top, the vertical karst lithofacies in the upper part, the gentle-dipping lateral karst lithofacies in the middle part, the impervious bed including granite and altered marine volcanic rocks at the bottom. They have inherited the pre-existing paleokarst in the multiperiod including the paleokarst by the magmatic hydrothermal fluid. This vertical zone pattern of tectonic lithofacies in the Gejiu Sn-Cu-W-Cs-Rb-polymetals ore- concentrated area may help us to reconstruct the hypogene paleokarst unconformable tectonic system. The hypogene paleokarst unconformable tectonic system have been produced by the paleo-hydrothermal, the paleo-volcanic hydrothermal fluids, the hydrothermal fluids derived from the volcanic eruption and magmatic intrusion, and are superimposed on the pre-existing karst system. These systems with prominent superimposition and reworking by the hydrothermal fluids during multiple periods have overlying lithologic seals, underwent burial diagenesis, hydrothermal reworked diagenesis, and superimposed diagenesis by interlayer detachment structure. These systems are the significant reservoir space for oil, gas, metals and nonmetals. Using mapping technique of the large-scale tectonic lithofacies, the Mesozoic-Cenozoic karst tectonic system in Gejiu, Yunnan have been studied, and three kinds of hypogene karst unconformable tectonic systems have been identified. These are respectively, the Paleogene hydrothermal type in Wulagen area in Xinjiang, the Permian volcanic hydrothermal fluid type, and the Proterozoic compound hydrothermal fluids derived from the volcanic eruption to magmatic intrusion on the top of the Xiaoliukou Group (Ar3-Pt1x) in the Dongchuan area in Yunnan, that have been anatomically studied. Materials and mechanisms for four different types of hypogene karst unformable tectonic system have been uncovered. It is believed that there is a high potential of discovering key strategic minerals hosted in hypogene karst unconformable tectonic system. |
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| Keywords: | paleokarst tectonic lithofacies karstification of acidic hydrothermal fluid superimposing diagenetic lithofacies paleokarst unconformable tectonic system key strategic minerals |
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