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| 兰坪盆地白秧坪铜钴多金属矿床中钴的成矿地球化学 | |
| 引用本文： | 李志明,刘家军,胡瑞忠,何明勤,刘玉平,李朝阳.兰坪盆地白秧坪铜钴多金属矿床中钴的成矿地球化学[J].矿物学报,2004,24(2):197-205. |
| 作者姓名： | 李志明 刘家军 胡瑞忠 何明勤 刘玉平 李朝阳 |
| 作者单位： | 1. 中国科学院,矿床地球化学开放研究实验室,贵州,贵阳,550002;中石化,石油勘探开发研究院,无锡实施地质研究所,江苏,无锡,214151;同济大学,海洋与地球科学学院,上海200092 2. 中国地质大学,北京,北京,100083 3. 中国科学院,矿床地球化学开放研究实验室,贵州,贵阳,550002 |
| 基金项目： | 国家重点基础研究发展规划项目(编号:G1999043208)，南京大学内生金属矿床成矿机制研究国家重点实验室资助项目(049805) |
| 摘 要： | 白秧坪铜钴多金属矿床产于下白垩统景星组陆相红色碎屑岩中，呈似层状、脉状分布于断裂带内，蚀变分带明显。研究表明：在原生矿石中钴主要赋存于独立矿物．辉砷钴矿中，同时钴可以类质同象赋存于砷黝铜矿及少量含钴黄铁矿中；在氧化矿石中，以钴华存在于矿石的表面。辉砷钴矿的成分和Co／Ni比值揭示钴的成矿作用与基性．超基性岩浆有关。矿床褪色蚀变岩、碳酸盐化蚀变岩矿石和正常岩石具有类似的稀土元素配分模式，即富集轻稀土而重稀土相对亏损、铈异常不明显而铕异常显著，但稀土元素总量、分异程度存在明显的差异。这可能与流体中带入稀土元素的方式、带入稀土的矿物类型和流体性质的差异等因素造成，反映成矿物质来源存在差异。相对正常岩石的微量元素含量，元素Cu、Co、As、Sb、Bi、Ag等在褪色蚀变岩、碳酸盐化蚀变岩和矿石中均相对富集，但在在褪色蚀变岩以亲石元素富集最明显，而在碳酸盐化蚀变岩和矿石中以显著富集亲硫元素(成矿元素)为主特征，表明在蚀变过程中，赋矿围岩本身没有为成矿作用提供主成矿元素，主成矿元素源自幔源的基性岩浆。由此认为钴的成矿作用可能主要与喜马拉雅期幔源的基性岩浆活动有关。 |
| 关 键 词： | 成矿地球化学 铜钴多金属矿床 钴 ：赋存状态 基性岩浆 |
| 文章编号： | 1000-4734(2003)04-0197-09 |
| 修稿时间： | 2003年6月11日 |
COBALT ORE-FORMING GEOCHEMISTRY OF THE BAIYANGPING COPPER-COBALT POLYMETALLIC DEPOSIT IN LANPING BASIN, YUNNAN |
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| LI Zhi-ming.COBALT ORE-FORMING GEOCHEMISTRY OF THE BAIYANGPING COPPER-COBALT POLYMETALLIC DEPOSIT IN LANPING BASIN, YUNNAN[J].Acta Mineralogica Sinica,2004,24(2):197-205. | |
| Authors: | LI Zhi-ming |
| Institution: | LI Zhi-ming~ |
| Abstract: | The Baiyangping copper-cobalt polymetallic deposit, which occurs as bedded and veined orebodies in fractures with distinct alteration zoning, is located in the continental red clastic rocks of the Lower Cretaceous Jingxing Formation. The study of occurrence of cobalt shows that it exists mainly in its independent mineral-cobaltite and in tennatites and few cobalt-pyrites isomorphically in primary ores, and also in erythrite on the surface of oxidation ore. The composition of and ratio of Co/Ni in cobaltite suggest cobalt ore-formation is related to basic-ultrabasic magma. Although the chondrite-normalized REE patterns of normal rocks, altered rocks, and ores are similar, they are characterized by LREE enrichment, HREE depletion, insignificant Ce-anomalies and significant negative Eu-anomalies. Distinct differences are noticed in the contents and the degree of differentiation of REE, which, we consider, may be ascribed to differences in way and mineral type carrying REE into normal rocks from fluids, and to the different properties between pre-ore-forming fluid and ore-forming fluid, reflecting the difference of ore source at different ore-forming stages. The elements Cu, Co, As, Sb, Bi and Ag are relatively enriched in discolouration altered rocks, carbonatization altered rocks and ores, as compared with the contents of trace elements in normal rocks. The lithophile elements are most enriched in discolouration altered rocks , whereas the sulphophile elements (ore-forming elements) are significantly enriched in carbonatization altered rocks and ores, suggesting wall-rock hosted ores did not provide main ore-forming elements for mineralization, and the main ore-forming elements are derived from mantle-source basic magma. Generally, cobalt metallogenesis may be related to the activity of basic magma derived from the mantle at the Himalayan stage. |
| Keywords: | copper-cobalt polymetallic deposit cobalt elementce occurrence REE and trace element basic magma Baiyangping |
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