我国东部白垩纪-早第三纪蒸发岩和生油岩沉积的区域构造背景

我国东部白垩纪-早第三纪蒸发岩和生油岩多分布在断陷盆地¹⁾的陆相地层中,主要受两个因素控制:一个是古气候因素;一个是区域构造因素。本文着重探讨区域构造因素。为了更全面地说明这一问题,首先简要地叙述一下古气候因素。

THE REGIONAL STRUCTURAL SETTING OF CRETACEOUSEARLY TERTIARY EVAPORITE AND SOURCE ROCK SEDIMENTS IN EASTERN CHINA

The fundamental factors which control such deposits as source rocks,coal series and evaporites are palaeo-climate and regional structural setting.With regard to regional structural setting,five main problems are discussed. 1.A single faulted basin of dustpan-shape is the fundamental structural element of Cretaceous-Early Tertiary evaporite-and source rock-bearing basins in Eastern China,which are complicated by secondary faults and diapirism of salt (or clay) beds in late stage.2. The single faulted basins are formed by tenssion. 3.The faulted lake basins have undergone several stages:(a) initial stage;(b) stage of development; (c) stage of contraction and (d) final stage. A large amplitude of depression of the lake basins are formed due to multi-tectonic movements,and the non-uniform uplifts of the basement have resulted in the discontinuous sediments and overlap of Tertiary.4. According to the evolutional stage of the faulted basins,the evaporites and source rocks may be divided into two main types. (a) The evaporites associated with source rocks are related to the stage of development of the basins; (b)The evaporites associated with red beds are related to the stage of contraction of the basins.5. The distribution of the evaporites is controlled by the morphology of the faulted basins and terrigenous fragment supplies around.