The exhalative genesis of the stratabound skarn in the Huanggangliang Sn-Fe polymetallic deposit of Inner Mongolia

The Huanggangliang deposit in Inner Mongolia is a large-size Fe-Sn polymetallic deposit in the central-southern section of Da Hinggan Ling area, where Jurassic-Cretaceous volcanic-plutonic rocks are widespread. Thus the deposit is regarded as an epigenetic hydrothermal deposit genetically related to the Mesozoic magmatism. Based on a study of geochemical characteristics of this deposit combined with the deposit geology, the authors have reached the following conclusions: (1)the stratabound ore-bearing skarn associated with magnetite ore and micro-disseminated tin is a peculiar example of exhalites;(2)REE geochemical characteristics show that the stratabound skarn in this deposit is different remarkably from the typical magmatic-hydrothermal contact metasomatic skarn but is quite similar to the modern sea floor hydrothermal fluid sedex deposit and associated hydrothermal sedimentary rock, and hence it should genetically belong to the hydrothermal exhalative type;(3)the relationship between carbon and oxygen isotopes in the stratabound ore-bearing skarn is on the whole comparable with that of many sedex-type sulfide ores and associated exhalites,implying a similar genesis for these deposits.