Skarn is one of the main ore bearing rocks in Laojunshan tin poly-metallic metallogenic region. This paper analysized occurrences and mineral compositions of the skarns systematically, combine with the study of microtexture, structure and petrochemistry, original rocks of the bearing skarns was discussed. Research has revealed that the original rocks of the skarns were intermediate-basic volcanic rocks, the rocks’ forming processes were related to marine volcanic activities. Southeast Yunnan province was a continental margin depressed basin during Cambrian period, the trace elements characteristics of ore bearing skarns were the same as volcanic-exhalative-sedimentary-origin orcks. During the early Caledonian period as a regional tension background, the basin crust became thinner and mantle material upwelling,the magma melting and mixed with the crust, and intermediate-basic volcanic eruption in the central of the depressed basin. The submarine volcano-sedimentary rocks could be found in Lower and Middle Cambrian in the study area, this reflect there are many stages of volcanic eruptions in the area. The ore bearing skarns were formed by volcano-sedimentary rocks mixed with normal marine sedimentary rocks, and impacted by the regional metamorphism of Indo-Chinese epoch.
Jia Fuju Nian Hongliang Gao Jianguo Guo Yuejin Yan Yongfeng . The geologic features and original rocks of ore bearing skarns in Laojunshan tin poly-metallic metallogenic region，Yunnan Province，China[J]. Chinese Journal of Geology, 2017, 52(3): 837-854.