| 贵州清镇林歹铝土矿顶、底板特征及其对铝土矿成矿的影响 |
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| 引用本文： | 杨瑞东,高军波,赵奎,余家腊,竺成林,高磊,陈吉艳,周汝贤.贵州清镇林歹铝土矿顶、底板特征及其对铝土矿成矿的影响[J].地质学报,2018,92(10):2155-2165. |
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| 作者姓名： | 杨瑞东 高军波 赵奎 余家腊 竺成林 高磊 陈吉艳 周汝贤 |
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| 作者单位： | 1) 贵州大学资源与环境工程学院，贵阳，550025,1) 贵州大学资源与环境工程学院，贵阳，550025,1) 贵州大学资源与环境工程学院，贵阳，550025,1) 贵州大学资源与环境工程学院，贵阳，550025,1) 贵州大学资源与环境工程学院，贵阳，550025,1) 贵州大学资源与环境工程学院，贵阳，550025,1) 贵州大学资源与环境工程学院，贵阳，550025,2) 贵州工程应用技术学院矿业学院，贵州毕节，551700 |
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| 基金项目： | 贵州省科技厅科技创新人才团队项目（黔科合[2018]04）、贵州大学学科建设项目和贵州省科技厅基金（黔科合LH字[2016]7046号）成果 |
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| 摘 要： | 清镇林歹铝土矿赋矿层位为下石炭统九架炉组，含矿层序具有典型的炭质页岩—铝土矿—铁质岩结构。本研究以铝土矿层顶、底板为主要研究对象，围绕林歹铝土矿顶板炭质页岩、底板喀斯特面及紫红色泥岩开展野外调查、地球化学分析测试、古生物化石鉴定等研究，结果发现在铝土矿顶部的炭质页岩中含大量的黄铁矿、丰富的植物和动物化石，植物化石主要为芦木、裸蕨类，由化石组合确定铝土矿形成时代为早石炭世。在炭质页岩中发现含腕足、腹足化石的白云岩夹层，证明炭质页岩形成于滨岸近海环境，由此推测铝土矿也形成近海湖泊环境。对含大量黄铁矿炭质页岩进行蒸馏水浸泡试验，发现炭质页岩浸泡液体pH值为1.5~2，呈现出强酸性，结合清镇林歹、小山坝等地铝土矿层与炭质页岩叠覆特征，认为铝土矿形成后，上覆炭质页岩在大气淡水淋滤下会对下伏铝土矿层起脱硅除铁作用，使铝土矿品位进一步提高。在铝土矿底板发现强风化白云岩砂、溶蚀裂隙、钙结层、湖泊沉积纹层等，认为寒武系白云岩中紫红色泥岩夹层很可能是铝土矿成矿母岩，且具有一定的找矿指示意义。
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| 关 键 词： | 成矿环境 生物化石 铝土矿顶底板 清镇 贵州 |
| 收稿时间： | 2017/9/18 0:00:00 |
| 修稿时间： | 2017/11/19 0:00:00 |
Roof and Floor Characteristics of Bauxite in Qingzhen, Guizhou,and their Implications for Bauxite Mineralization |
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| YANG Ruidong,GAO Junbo,ZHAO Kui,YU Jial,ZHU Chenglin,GAO Lei,CHEN Jiyan and ZHOU Ruxian.Roof and Floor Characteristics of Bauxite in Qingzhen, Guizhou,and their Implications for Bauxite Mineralization[J].Acta Geologica Sinica,2018,92(10):2155-2165. |
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| Authors: | YANG Ruidong GAO Junbo ZHAO Kui YU Jial ZHU Chenglin GAO Lei CHEN Jiyan and ZHOU Ruxian |
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| Abstract: | The Lindai bauxite deposit with typical sequence of carbonaceous shale- bauxite- iron rock occurs in the Jiujialu Formation of the Lower Carboniferous. With the roof and floor of bauxite as the main research objective, this study investigated top carbonaceous shale, bottom purple mudstone and karst feature using geochemistry methods and paleontological identification, as well as field survey. The results show that the top carbonaceous shale contains abundant pyrite and plant fossils, and minor animal fossils. The plant fossils are mainly archaeocalamites scrobiculatus and sublepidodendron, the assemblage of which suggests that the bauxite deposit likely formed in the Early Carboniferous. Brachiopods and gastropods fossils discovered in dolomite interlayer indicate that the carbonaceous shale formed in a coastal environment. This also suggests that the Lindai bauxite deposit deposited in offshore lake environment. The study performed an immersion test on samples from pyrite carbonaceous shale in distilled water. The results show that the immersion liquid presents strong acidity with pH values of 1.5~2. According to overlaying relationship of strata (the top carbonaceous shale and bauxite) in Lindai, Maochang and Xiaoshaba mines, this study found that the overlying carbonaceous shale after the formation of bauxite removed Si and Fe out of underlying bauxite layers under the leaching effect of meteoric water, thus improving the grade of bauxite ore deposits. Discovery of strong weathering sandy dolomite, dissolution cracks, calcium junction and lacustrine sediments suggests that the purple red mudstone within Cambrain dolomitic rock was likely the source rock for bauxite mineralization and has some significance for exploration. |
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| Keywords: | mineralization environment biological fossil roof and floor of bauxite Qingzhen Guizhou |
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