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大兴安岭嫩北农场一带出露一套以中酸性火山熔岩为主的晚古生代地层.前人对这套地层划分、时代归属存有很大分歧.原因是:一方面区域上火山岩出露厚度大、露头不连续、区域植被茂盛,顶底多为断层接触或被第四系所覆盖;另一方面由于存在于火山岩地层中的化石较少或缺少精确的同位素年代学数据.本文在新近研究成果的基础上,依据地层岩石组合对比及锆石U-Pb年代学资料,将这套晚古生代地层进行了重新厘定为大石寨组.
A set of late Paleozoic strata dominated by medium-acidic volcanic lava is exposed in the Nenbei Farm in the Greater Hinggan Mountains. The predecessors have very different opinions on this stratigraphic division and the ownership of the times. The reasons are as follows: on the one hand, the exposed thick volcanic rocks , Discontinuous outcrops, lush vegetation in the area, most of the tops are fault-contacting or covered by Quaternary, and on the other hand, there are few fossils in the volcanic strata or lack of accurate isotope dating data.In this paper, Based on the comparison of stratigraphic rock assemblages and zircon U-Pb chronological data, this Late Palaeozoic strata was re-determined as Dashizhai Formation.