| 贵州开阳磷矿地区下寒武统牛蹄塘组地层层序及其As、Sb、Au、Ag丰度异常与赋存状态研究 |
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| 引用本文： | 张岳,颜丹平,赵非,李旭拓,邱亮,张翼西.贵州开阳磷矿地区下寒武统牛蹄塘组地层层序及其As、Sb、Au、Ag丰度异常与赋存状态研究[J].岩石学报,2016,32(11):3252-3268. |
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| 作者姓名： | 张岳 颜丹平 赵非 李旭拓 邱亮 张翼西 |
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| 作者单位： | 中国地质大学地球科学与资源学院, 北京 100083,中国地质大学地球科学与资源学院, 北京 100083,中国地质大学地球科学与资源学院, 北京 100083,中国地质大学地球科学与资源学院, 北京 100083,中国地质大学地球科学与资源学院, 北京 100083,中国地质大学地球科学与资源学院, 北京 100083 |
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| 基金项目： | 本文受“973”计划项目（2014CB440903）资助. |
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| 摘 要： | 贵州开阳磷矿地区出露较为完整的下寒武统黑色岩系层序,这套黑色岩系中富含多种金属元素,但目前对岩系中主要低温成矿元素As、Sb、Au、Ag的地球化学背景异常与分布规律了解极少,对其形成背景与赋存状态无法进行深入讨论。本文以开阳磷矿地区下寒武统牛蹄塘组黑色岩系剖面作为研究对象,通过详细的野外地质调查、系统采样并进行地球化学分析、全岩硫同位素分析及黄铁矿电子探针分析,划分了详细的牛蹄塘组地层层序,对主要低温成矿元素(As、Sb、Au、Ag)的丰度异常、富集特征及赋存状态进行了研究,结果表明,黑色岩系中普遍富集As、Sb、Ag三种主要低温成矿元素,Au也在大部分层位富集。四种元素具有层控性的特点,在牛蹄塘组下部有机质含量较高的黑色白云质粉砂质页岩和黑色页岩层位中具有较高的元素丰度异常,在泥岩和粉砂岩混合层位元素丰度异常较低,钙质成分含量较高的层位元素含量较低。黄铁矿是黑色页岩中金的主要赋存矿物,也是Sb的重要赋存矿物,同时是Ag和As的次要赋存矿物;不同类型的黄铁矿,元素富集规律也不相同:As、Ag更容易富集在不规则集合体和草莓状黄铁矿中,Sb和Au则在散布的单颗粒黄铁矿中富集系数最高。
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| 关 键 词： | 牛蹄塘组 地层层序 As、Sb、Au、Ag 丰度异常 赋存状态 |
| 收稿时间： | 2016/4/11 0:00:00 |
| 修稿时间： | 2016/8/14 0:00:00 |
Stratigraphic sequences, abundance anomalies and occurrences of As, Sb, Au, Ag in the Lower Cambrian Niutitang Formation in Kaiyang Phosphate Mine area |
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| ZHANG Yue,YAN DanPing,ZHAO Fei,LI XuTuo,QIU Liang and ZHANG YiXi.Stratigraphic sequences, abundance anomalies and occurrences of As, Sb, Au, Ag in the Lower Cambrian Niutitang Formation in Kaiyang Phosphate Mine area[J].Acta Petrologica Sinica,2016,32(11):3252-3268. |
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| Authors: | ZHANG Yue YAN DanPing ZHAO Fei LI XuTuo QIU Liang and ZHANG YiXi |
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| Institution: | School of Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China,School of Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China,School of Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China,School of Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China,School of Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China and School of Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China |
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| Abstract: | The black shale sequences of the Lower Cambrian Niutitang Formation expose well in the Kaiyang Phosphorite area in Guizhou Province. The black shale sequences deposited in a special sedimentary environment with rich polymetallic elements have become the focus of research in recent years. However, the geochemical background anomalies and occurrence of the main elements of low-temperature mineralization, such as As, Sb, Ag, Au in these black shales, have not been documented, and thus the implications were not well understood. In this contribution, stratigraphic sequences along the selected geological profiles are detailed investigated and divided. Geochemistry composition, sulfur isotope composition of whole-rock samples and pyrites are analyzed mainly using ICP-MS and EPMA (electron probe microanalysis), respectively, after sampled the Niutitang Formation profiles methodically and systematically. The results indicate that As, Sb and Ag are enriched in all layers, while Au is enriched in most layers. The enrichment of these four elements show strata-bound characteristics, i.e., there are high positive abundance anomalies of As, Sb, Ag and Au in black dolomite silty shales and black shales with higher content of organic matter in the lower part of the Niutitang Formation, but low abundance anomalies in the layer with higher content of calcium and mixing layers of mudstone and siltstone. Primary pyrites in black shales are the main host mineral for element Au, the important occurrence mineral for element Sb, and the secondary occurrence mineral for elements Ag and As. Meanwhile, different types of pyrites showed different elements enrichment patterns in our analysis. As and Ag are more easily to enrich in irregular aggregate and framboids pyrites, while Sb and Au have higher concentration coefficients in single pyrite grains distributed in matrix. |
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| Keywords: | Niutitang Formation Stratigraphic sequence As Sb Au and Ag Abundance anomalies Occurrences |
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