Abstract:
The Lijiawan manganese deposit is one of the typical "Datangpo type" deposits in Songtao area of Guizhou province, which is a large concealed type manganese deposit disicovered in recent years and is also the deep peripheral extension of the Yanglizhang manganese ore bodies. Based on the field geological investigation, this paper focuses on the study of the geological, geochemical characteristics and its surrounding rocks of this manganese deposit, and then the ore-forming sources, genetic and mineralized environment of this deposit have been discussed. The results show that the ores occurred as massive, banded and mottled types, with mainly manganese minerals of rhodochrosite and greinerite. The content manganese layer has high MnO, CaO and MgO contents, but it has low TiO
2, Al
2O
3, K
2O and Na
2O contents, and the manganese-bearing rock series are enriched in Ba, Th, Rb, Cs, Zr, Cs and Ga elements. The SiO
2/Al
2O
3 ratio shows the materials were not sourced from normal terrigenous;The Al/(Al+Fe+Mn), (Fe+Mn)/Ti, Fe/Ti, Y/Ho, Nb/Ta and U/Th ratios, Fe-Mn-(Cu+Co+Ni) * 10 diagram show that the manganese ore has hydrothermal sedimentary characteristics;The Mn/Fe, Sr/Ba, V/(V+Ni) ratios reveal that the manganese ore was formed in shallow water and reductive sedimentary environment. The total REE is higher, with LREE enrichment;The manganese-bearing rock series have Eu and Ce anomalies;The La/Ce ratio, the REE and HREE values reflecct that the manganese deposition process was effected by hydrothermal activity, with a tectonic environment of passive continental margin. According to the characteristics mentioned above, it's included that the Lijiawan manganese deposit was formed in strong reducing environment, which was sourced from the mixing of hydrothermal and normal deposition.