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本文系统分析了目前确定云开群地质年代的同位素年龄数据和微古植物化石的可利用性和存在的问题,根据云开群牛辰坳组/兰坑组中化学沉积成因硅质岩测得的~(40)Ar/~(39)Ar坪年龄872.8±8.6 Ma,并结合云开群罗罅组变质英安斑岩中颗粒锆石分层蒸发法年龄922～940 Ma,确定了云开群的地质年代为新元古代青白口纪。按其时代和岩性序列特征将其与丹洲群和板溪群进行对比。文中指出前人建立并命名作为岩石地层单位的高州岩群和黄岭岩组不符合地层划分命名原则,因而是不恰当的。根据野外观察,对比研究岩性和追索构造展布,本文认为黄岭岩组中的沉积变质岩残留体可能就是云开群兰坑组地层。高州群其余两个组地层的地质年代和对比则还有待进一步的研究。
This paper systematically analyzes the isotopic age data and the availability and existing problems of microfossil from the Geological Period of Yunkai Group. According to the chemical sedimentary origin chert from the Niuchen Au / Lankeng Formation in Yunkai Clique The Ar 40 ~ Ar 39 ~ Ar geopotential age is 872.8 ± 8.6 Ma and the ages of 922 ~ 940 Ma are determined by zircon zircon stratification in the metamorphosed Yingan porphyry of the Yunkai Group. Geological age group for the Neoproterozoic Qingbaikikiji. It is compared with the Danzhou and Banxi groups according to the characteristics of its time and lithology. The paper points out that it is inappropriate for Gaozhou Group and Huangling Group, formerly established and named as lithostratigraphic units, not to meet the principle of nomenclature of stratigraphic division. According to the field observation, comparative study of lithology and recourse tectonic distribution, this paper believes that the residual metamorphic rocks in the Huangling Formation may be the formation of the Lankai Group Lankeng Formation. The geological age and contrast of the remaining two formations in the Gaozhou group have yet to be further studied.