| 黔中开阳地区震旦纪陡山沱期富磷矿沉积特征与成矿模式* |
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| 引用本文： | 张亚冠,杜远生,陈国勇,刘建中,王泽鹏,徐圆圆,谭代卫,李磊,王大福,吴文明.黔中开阳地区震旦纪陡山沱期富磷矿沉积特征与成矿模式*[J].古地理学报,2016,18(4):581-594. |
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| 作者姓名： | 张亚冠 杜远生 陈国勇 刘建中 王泽鹏 徐圆圆 谭代卫 李磊 王大福 吴文明 |
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| 作者单位： | 1.中国地质大学(武汉)生物地质与环境地质国家重点实验室,湖北武汉 430074;2.贵州省地质矿产勘查开发局科技信息处,贵州贵阳 550004;3.贵州省地质矿产勘查开发局105地质大队,贵州贵阳 550018 |
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| 基金项目： | 中国地质调查局地质调查项目(编号:12120114016501);贵州省地质矿产开发局项目(编号:黔地矿办发[2013]56号)联合资助~~ |
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| 摘 要： | 黔中开阳地区在震旦纪陡山沱期全球成磷事件的大背景下,发育了厚度较大的富磷矿层。通过岩石薄片观察、地层对比与划分及沉积相分析等手段,探讨黔中开阳地区震旦纪陡山沱期磷矿床沉积特征与成矿模式。结果表明:(1)开阳地区陡山沱期处于黔中古陆北缘的磷质海岸环境,磷矿层中分布最广泛、品位最高的矿石类型为砂屑磷块岩,为富磷沉积物在沉积、成岩过程中遭受多期次冲刷破碎、暴露淋滤及堆积胶结的产物。(2)开阳地区古地理环境和动荡的海水条件控制了磷矿的沉积和高品位矿石的分布,洋水、永温等地在震旦纪陡山沱期所处的海水深度适中的临滨带为成矿优势地带,而水体过浅的前滨带和过深的远滨带均不利于磷质的聚集和成矿。(3)开阳地区动态磷矿床成矿模式表明,陡山沱期海平面的频繁进退使临滨带已沉积的磷块岩遭受多期次的冲蚀、暴露、淋滤、胶结及磷质再沉积作用;通过物理分选作用和风化淋滤作用最终使磷质聚集,是研究区富磷矿形成的主要原因。
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| 关 键 词： | 黔中 震旦纪 陡山沱期 磷矿 成矿模式 |
| 收稿时间： | 25 January 2016 |
Sedimentary characteristics and mineralization model of high￣grade phosphorite in the Sinian Doushantuo Age of Kaiyang area,central Guizhou Province |
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| Zhang Yaguan;Du Yuansheng;Chen Guoyong;Liu Jianzhong;Wang Zepeng;Xu Yuanyuan;Tan Daiwei;Li Lei;Wang Dafu;Wu Wenming.Sedimentary characteristics and mineralization model of high￣grade phosphorite in the Sinian Doushantuo Age of Kaiyang area,central Guizhou Province[J].Journal of Palaeogeography,2016,18(4):581-594. |
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| Authors: | Zhang Yaguan;Du Yuansheng;Chen Guoyong;Liu Jianzhong;Wang Zepeng;Xu Yuanyuan;Tan Daiwei;Li Lei;Wang Dafu;Wu Wenming |
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| Institution: | 1.State Key Laboratory of Biogeology and Environmental Geology,China University of Geosciences(Wuhan),Wuhan 430074,Hubei;2.Science and Technology Information Department,Bureau of Geology and Mineral Exploration and Development of Guizhou Province,Guiyang 550004,Guizhou;3.Geological Brigade 105,Brueau of Geology and Mineral Exploration Development of Guizhou Province,Guiyang 550018,Guizhou; |
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| Abstract: | There were thick and high-grade phosphorite beds in Kaiyang area of central Guizhou Province during the global phosphogenesis events in the Sinian Doushantuo Age. This paper used thin sections observation,stratigraphic comparison and subdivision and sedimentary facies analysis to study the sedimentary characteristics and mineralization model of phosphorite deposits in the Sinian Doushantuo Age in Kaiyang area,central Guizhou Province. The result showed that: (1)Kaiyang area was located in north margin of Central Guizhou Old Land which was a phosphorus beach during the Sinian Doushantuo Age. The high-grade phosphorite ore in Kaiyang area was mainly composed of sand clastic phosphate rocks which were formed in the process of sedimentation-diagenesis of phosphorus-rich deposits,during which they were erosion and broken,exposed and leached,accumulated and cemented repeatedly. (2)The palaeogeographic environment and unstable seawater condition controlled the deposition and enrichment of phosphorite in Kaiyang area. Shore face zone like Yangshui or Yongwen which were in a depositional condition with moderately-deep seawater in the Sinian Doushantuo Age was the advantageous metallogenetic zone. Foreshore zone with too shallow seawater and offshore zone with too deep seawater were unbeneficial for phosphorus aggregation and mineralization. (3)The dynamic mineralization model of phosphorite deposits in Kaiyang area showed that frequent transgression and regression during the Doushantuo Age made phosphate rocks which originally deposited in shore face zone experienced multi-stages erosion,exposure,leaching,cementing and redeposition. Physical winnowing action,weathering and leaching gathered phosphorus and ultimately led to the formation of high-grade phosphorite. |
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| Keywords: | central Guizhou Province Sinian Doushantuo Age phosphorite mineralization model |
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