Mapping test of lithological association-lithofacies in continental volcanic rock field:A case study of western Taipusi caldera, in Inner Mongolia

The mapping method for continental volcanic rock field with the purpose of reflecting the volcanic characteristics is different from the traditional method suitable for sedimentary area, and this problem has been groped for over half a century in China. The "diplex mapping method"(lithofacies+stratigraphy) and the "volcanic construction-lithologic rock facies-volcanic sequence" have been explored, with important progress and achievement obtained in local area. Nevertheless, the fact that volcanic rock was mapped as stratum (formation) did not get out of habitual practice in actual mapping at the national level. It is still a significant task to explore and summarize mapping method suitable for continental volcanic rocks. Volcanic facies is a foundation for restoration of the processes of volcanism and ancient volcanic apparatus, and should be shown as key elements in volcanic geological maps, whereas lithological association is a most reliable basis for assigning types of lithofacies. The continental volcanic characteristics can be well reflected on the basis of lithological association-lithofacies mapping.