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前寒武纪经历了漫长的地质历史时期,约占整个地球地质历史六分之五还要多些。这一时期的地层分布也很广,各个大洲都有出露,就出露地表或为不厚的第四系所覆盖的前寒武系而言,其所占面积将近世界陆地总面积的五分之一。此外,在前寒武纪地层内有着各种各样的矿产。因此,对于前寒武纪地层的研究是有着重要意义的。前寒武纪地层的划分问题,虽然广大地质工作者常常把它划分为两部分,其上部叫元古
Precambrian experienced a long period of geological history, accounting for about six-fifths of the Earth’s geological history even more. Stratigraphic distribution during this period is also very wide, there are exposures on all continents, to reveal the surface or not thick Quaternary covered Precambrian, its share of the world’s land area of nearly five One part. In addition, there are a variety of minerals in Precambrian formations. Therefore, the study of Precambrian strata is of great significance. Precambrian stratigraphic division problem, although the majority of geologists often divide it into two parts, the upper part called Proterozoic