湖南衡阳盆地沉积相及构造发展的若干问题

本文通过湖南衡阳盆地主要地层剖面(主要是白垩系)沉积特征的描述,探讨了盆地内沉积相在纵向上的分布规律,并由此来认识盆地内沉积建造的演变过程及由其所反映的盆地构造演化方向。同时,本文还探讨了盆地在燕山阶段的形成和发展,特别是喜马拉雅阶段时期盆地形成以后因挤压而受到改造,形成了一系列逆掩断层和推覆体。盆地今天的面貌是这一改造的结果。

SOME FEATURES OF THE SEDIMENTARY FACIES AND THE TECTONIC DEVELOPMENT OF THE HENGYANG BASIN, HUN AN PROVINCE

Based on an analysis of the features of the sediments, sedimentary structures, the relationships among the sequences in the basin and the tectonic disturbances after the basin was formed, some suggestions are given as follows: 1. The Hengyang Basin is a down-warping basin developed on a Caledonian basement. The basin filled with thick clastic-sulfate rocks during the Cretaceous-Paleogene. The types of sedimentary facies in the basin are characterizeda wide range of piedmont-proluvial, fluvial, delta and lacustrine facies. y 2. The succession of the sedimentary facies above mentioned suggests adevelopment process from the paramolasse association, the inland fluvio-lacu-strine red clastic association, and the inland salt lake saline association, finally to the inland plain clastic association. 3. The formation of the Hengyang basin was preceded by the early phase of the Yanshanian Movement and ended with the early stage of the Himalayan. The effect of the succeeding phases of the date Yanshanian was also imprinted on the characteristics of this basin.1.There was intense compression in a northwest-southeast direction in the basin during the Late Himalayan Stage, forming a series of thrusts. The tectonic pattern of the basin has been significantly reworked. The pattern of the basin and the features of the gravity and magnetic anomalies that we see today are the products of this rework.