湖南花垣民乐震旦系锰矿床同位素地质研究

民乐碳酸锰矿层中含丰富的硫、氧、碳、铷和锶组分,经采样分析,基本掌握其同位素特征。根据同位素组成,本文探讨了成锰期古地理--梅湾潮坪-泻湖环境,成锰介质的古温度,成矿物质主要来源和成锰时代。

ISOTOPE GEOLOGICAL STUDY OF MANGANESE DEPOSIT IN MINLE AREA,HUNAN PROVINCE

The manganese carbonate beds in Minle area are abundant in isotopes S, O. C, Rb and Sr by sampling and determining. The characteristics of these isotopes are, δ34S 46.6-58.59‰ (52.17‰ on an average), δ18OPDB-3.72-9.06‰ , δ13C_PDB-8.19--12.98‰ 87Rbμg/ g 0.06827-0.45154, 86Srμg/ g 0.0837-0.18809, 87Rb/ 86Sr 0.42632-5.0459, 87Sr/ 86Sr 0.70935 ± 0.00016-0.75808 ± 0.00025. According to the comprehensive study of these isotopes, this paper has inquaired into the paleogeographic environments of metallogenic epoch of manganese, the paleotemperatures of metallogenic medium of manganese, the major source of the metallogenic materials of manganese, the source and nature of Mn-bearing solution, and the period of metallogenic manganese. Conclusions are drawn by the author as follows that the environments of the manganese carbonate were semi- limit- confin weak salt water tidal flat- lagoon and they did not emerge in evaporation; the paleotemperature of metallogenic medium of manganese was 35. 72 ° -40.88℃ , much higher than that of the modern seawater; the major source of manganese was the material of weathering and separation of continental crust; the Mn-bearing solution should be seawater; the period of metallogenic manganese was 728 ± 27 Ma (B.P.), belonging to Minle to Minle period of Early Sinian period. Thus, the important information and data were contributed in the metallogenic manganese period and the origin studying of Minle manganese deposit