由中国东部前寒武纪地质构造演变探讨构造对沉积的控制

Discussion on Geotectonic Controlled Sedimentation Based on Geotectonic Evolution of Precambrian in Estern China

本文根据中国东部的太古宙与元古宙早期的岩系发育及地质构造特征,探讨了当时的构造与沉积环境,指出构造条件对古沉积作用的影响。在经历3个大地构造旋回之后,中国东部的华北与东北南部地区形成了古陆壳;而元古宙早期的地层属于裂陷构造内的沉积。文中指出不能以均变论观点来分析前寒武纪的古老岩系。

This paper deals with the development of the Archean and Early Proterozoic rock units and their between tectonic features, and then discusses the relationship tectonic environment and sedimentation.The authors emphasized that the ancient sedimentation may be controlled by tectonic settings, There are three tectonic cycles in precambrian occurred in eastern China, termed Qianxi. Fuping and Wutai.The ancient continental crust of that period may be formed just in the regions of northern China.It is suggested that, in the studying of Precambrian earth crust should be considered the tectonic settings which associated with sedimentary environment.For the high temperature and pressure existing in the mantle, it is believed the komatiite was formed in Archean, and the greenstone belt which widely spread may represented the stablity of cratonic regions. Based on the results of investigations of Archean metamorphic sequence for several years, it suggests that the development of nuclei of ancient continents may be with progression and certain tendency, such as depletion of vertical movement and increase of horizontal movement with time.In addition, the characters of deformation may be from plastic change into rigid ones. thus, on the synclinoria in NE trend stacked some fractures and led to formed proto-taphrcgens, in which the Early Proterozoic strata had been deposited, the location of which was at the continental margins and intracontinental settings.This tectonic pattern of framework had controlled the formation of the Proterozoic sediments during that period.However, the carbonate rocks can be represent the differentation of the ancient earth crust, such as Wutai Group which consists of basic to acidic volcanics and elastics interbedded with some carbonate rocks, as well as with rhythmic flysch feature.The regional metamorphism is mainly derived from Wutai Movement stage I. During the Stage II and Luliang Movement, because of the strength of tectonic movement had been depleted, there isn' t obvious regional metamorphism. The enlarging and thickening of continental crust caused by tectono-thermal events, are likely to form some nuclei of ancient continents worldwidely. In summary, it is emphasized that in the studying of Precambrian system, the uniformitarianism is not suitable to adapt, because of the characteristics of the earth s crust is different from the latter plates. which was formed in Late Paleozoic.