| 摘要: |
| 贵州道坨锰矿是2010年发现的一个大型碳酸锰矿床,含矿层位为南华系大塘坡组底部的含锰黑色页岩,主要含锰矿物为菱锰矿。通过对锰矿石全岩与提取出的菱锰矿进行稀土元素对比分析发现:(1)不同Mn含量的锰矿石的ΣREE在(171.84~243.08)×10-6之间,提取的菱锰矿的ΣREE在(32.52~135.69)×10-6之间,菱锰矿的ΣREE占全岩ΣREE的比例从15%到80%不等。菱锰矿的ΣREE随着锰含量的升高而升高,且稀土元素配分模式都呈轻稀土含量少,中稀土富集,重稀土相对中稀土减少的"帽"式配分模式,而全岩的配分模式基本是平坦的直线型。随着全岩中Mn含量的升高,全岩和菱锰矿的配分模式越来越相似;(2)菱锰矿的δCe值在1左右,且随着Mn含量的升高。δCe值变大,这可能是因为Ce在锰氧化物或氢氧化物逐渐沉积富集的过程中,逐渐地被吸附,而造成了异常值的逐渐增大,说明菱锰矿的形成经过了锰氧化物或氢氧化物的阶段;(3)分别比较菱锰矿中Mn和P与轻、中、重稀土的相关性,Mn与中稀土的相关性最差,而P与中稀土的相关性最好。因此菱锰矿所表现出的中稀土富集的现象可能是其中的磷酸盐引起的,而磷酸盐与菱锰矿的共存可能是因为当时环境中磷与锰的分离不彻底造成的。 |
| 关键词: 道坨 菱锰矿 稀土元素 磷元素 |
| DOI： |
| 附件 |
| 投稿时间：2014-11-01修订日期：2014-11-10 |
| 基金项目: |
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| REE characteristics of rhodochrosite from the Daotuo manganese deposit in Guizhou |
| PEI Hao-xiang, FU Yong, XU Zhi-gang, WEN Hong-li, AN Zheng-ze |
(1. College of Resources and Environmental Engineering, Guizhou University, Guiyang 550000, Guizhou, China;
2. Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 100037, China;
3. National Research Center for Geoanalysis, Beijing 100037, China;
4. No. 103 Geological Party, Guizhou Bureau of Geology and Mineral Resources, Tongren 554300, Guizhou, China) |
| Abstract: |
| The Daotuo manganese deposit in Guizhou is a large-scale carbonate manganese deposit discovered in 2010 and hosted in the manganese-bearing black shales with rhodochrosite as the main manganese-bearing mineral at the base of the Nanhuan Datangpo Formation. The results of research in this study are generalized as follows. (1) The ΣREE contents range between 171.84×10-6 and 243.08×10-6 for the manganese ores with different manganese contents; 32.52×10-6 and 135.69×10-6 for the selected rhodochrosite in which the ΣREE contents amount to 15% and 80% of the whole manganese-bearing rocks, and ΣREE contents in rhodochrosite tend to increase with the increase of manganese contents. The REE distribution patterns for the rhodochrosite exhibit the "cap"-type distribution patterns showing low LREE contents, enriched MREE contents and relatively lower HREE contents than MREE contents, while almostly smooth straight distribution patterns for the whole manganese-bearing rocks. (2) The δCe values equal to about 1, and increase with the increase of Mn contents, indicating the gradual absorption of the element Ce during the deposition and enrichment of the manganese oxides and hydroxides. (3) There is no correlation between Mn and MREE, and a good correlation between P and MREE. It is inferred that the MREE enrichment in rhodochrosite may be caused by the phosphates, and coexistence of the phosphates and rhodochrosite may be ascribed to the incomplete separation of the elements P and Mn in the depositional environments at that time. |
| Key words: Daotuo rhodochrosite REE the element P |
