| 广西下雷锰矿床气液喷溢沉积构造的发现及地质意义 |
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| 引用本文： | 卢安康,周琦,覃永军,朱路艳,袁良军,黄宗添.广西下雷锰矿床气液喷溢沉积构造的发现及地质意义[J].地质科技通报,2021,40(6):124-139. |
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| 作者姓名： | 卢安康 周琦 覃永军 朱路艳 袁良军 黄宗添 |
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| 基金项目： | 中央引导地方科技发展资金项目黔科中引地[2021]4027贵州省高层次创新型人才项目黔科合平台人才[2018]5631-2贵州省高层次创新型人才项目[2020]6019贵州省优秀青年科技人才项目黔科合平台人才[2019]5654贵州省科技计划项目黔科合支撑[2019]2868贵州省地矿局地质科研项目黔地矿科合[2019]2号贵州省地矿局地质科研项目黔地矿科合[2018]34号 |
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| 摘 要： | 广西大新下雷泥盆纪锰矿床是我国首个超大型锰矿床。通过对矿床含锰岩系、矿石组合、矿石成分、矿石结构构造综合分析研究，在锰矿体中发现了可能为气液喷溢沉积成因的角砾状、脉状以及网脉状构造的锰矿石。同时在矿石中普遍见热液成因的含锰硅酸盐矿物和硫化物，如蔷薇辉石、锰铁叶蛇纹石、黄铁矿、黄铜矿、锰帘石等。通过对矿区钻孔原始编录资料综合分析，在控制该锰矿床形成分布的泥盆纪晚期的下雷-土湖Ⅳ级地堑盆地中，成功恢复识别出3条锰矿成矿期同沉积断层。发现角砾状锰矿石等在空间上集中成群分布，应是导致锰矿形成的古气液喷溢口的分布位置，空间分布受锰矿成矿期同沉积断层的控制。通过与贵州松桃南华纪"大塘坡式"气液喷溢沉积型锰矿床进行对比，发现二者气液喷溢沉积构造等特征较为相似，故认为广西大新下雷泥盆纪锰矿床的成因类型可能与南华纪"大塘坡式"锰矿相似，具有气液喷溢沉积型锰矿床的一些典型特征，这为"下雷式"锰矿成矿研究与找矿预测提供了新的思路。
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| 关 键 词： | 气液喷溢沉积构造 同沉积断层 发现 下雷锰矿 广西 |
| 收稿时间： | 2021-02-18 |
Discovery and geological significance of gas-liquid spouting expulsion and effusion depositional structures at Xialei manganese deposit in Guangxi |
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| Abstract: | The Daxin Xialei Devonian manganese deposit in Guangxi is the first super-massive manganese ore deposit ever discovered in China. Here we conducted detailed petrographic studies on manganese-bearing sequence, ore mineral assemblages and their textures and structures. Our work reveal that the brecciated, vein-bearing and stockwork manganese ore minerals may form correspondingly to the expulsion and effusion of the gas and liquid-rich fluid. In addition, prevailing manganese-bearing silicate and sulfide minerals (rhodonite, manganese-iron chlorophyllite, pyrite, chalcopyrite, manganite, etc.) of hydrothermal origin are observed among the ores. Further comprehensive examinations of the original borehole data of the mining area lead to two major outcomes.First, three syndepositional faults are successfully recovered and identified in Late Devonian Xialei-Tuhu Ⅳ-graben basins, which controls the formation and spatial distribution of the manganese ore deposit.Second, brecciated manganese ore minerals appear to be clustered in space, and the localities of which may correspond to the locations of the ancient gas-liquid expulsion and effusion centers that give rise to the formation of manganese ore. Notably, the spatial distribution of the fossilized gas-liquid centers is controlled by the syndepositional faults developed during the formation of manganese ore deposit. Given the observation that Xalei Devonian manganese ore deposit shares comparable expulsion and effusion depositional features to Nanhua Datangpo gas-liquid depositional manganese ore deposit at Songtao of Guizhou Province, it is therefore argued that both Xialei and Datangpo manganese ore developed by similar mechanisms. This study sheds light on a better understanding of the metallogenic mechanism(s) and will place better constraints on the future explorations of Xialei manganese ore deposit. |
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