层序地层学在前寒武纪地层研究中的应用──以河南省西部震旦系为例

Application of Sequence Stratigraphy to Precambian Strata-A case study on the Sinian in Western Henan Province

运用层序地层学原理和工作方法，对豫西震旦系进行了详细地研究，识别出三个I类层序，并建立起了各层序的等时格架，系统地研究了地层沉积相带在层序格架中的分布规律和成因联系。认为相对海平面变化是本区层序、体系域形成的主导因素。以相对海平面升降作为等时周期，不同成困背景下的沉积物就具有等时性，可以对比。同时，对相应的海平面变化曲线的绘制方法进行了尝试。

The paper focuses on sequence stratigraphy of the Sinian in Western Henan Province. Based on the theory of sequence stratigraphy, three type I sequences have been identified, in which the first two sequences correlate to the Huanglianduo Formation and Dongjia Formation, respectively, and the third one includes both the Luoquan and Dongpo Formations. After estabhshing their sequence isochronic framework, the author ana1yzes systematical1y the distribution patterns and genetic relations of the strata and sedimentary facies zones within the framework, and then proposes that the formation of the Sinian sequences and their system tracts in the study area was controlled primarily by the relative sea-level changes. The sediments which deposited within the same sea-level changes, although they have different sedimentary environments and different components, are isochrononic and can be correlated. Finally, the author proposes a method how to drow the curves of relative sea-level changes.Based on the research result, the author concludes that the theory of sequence stratigraghy can be generally applled to the Precambian, such as the Sinian, by identifying the key boundaries, especially the sequence boundary (SB) and the maximum flooding surface (mfs), and analyzing the features of the parasequences,parasequence sets and system tracts within a sequence. The method establishes a good base for the classification and correlation of the strata study. But the hierarchy of the sequence cannot be precisely determined because of low-studying-level and short of accurate dating, therefore further studies are necessary.