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

Abstract: 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