SOME FEATURES OF THE SEDIMENTARY FACIES AND THE TECTONIC DEVELOPMENT OF THE HENGYANG BASIN, HUN AN PROVINCE
湖南衡阳盆地沉积相及构造发展的若干问题

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.