下扬子地区晚古生代含油气盆地原型

THE PROTOTYPES OF LATE PALEOZOIC PETROLIFEROUS BASINS IN LOWER SECTION AREA OF YANGTZE RIVER

丁道桂 李萍 吕俊祥

Ding Daogui Li Ping Lü Junxiag

地质矿产部石油地质中心实验室

Central Laboratory of Petroleum Geology, Ministry of Geology and Mineral Resources

笔者在下扬子地区晚古生代含油气盆地的基底特征的基础分析上,着重叙述克拉通台向斜拗陷盆地的原型特征。从沉积及沉降、构造发展等因素对下扬子区晚古生代盆地作构造区划,划分其三个发展阶段,即断陷—拗陷—转化。印支—早燕山运动以来主要是自东南向西北强烈褶皱、推掩的板内变形,其主要构造样式为基底拆离。对下古生界作叠加和保存,前缘拗陷内发育了中新生界,对油气生成与聚集是有利的因素。

The characters of deposition and subsidence in lower section area of Yangtze River are discussed in this paper.The authors of this paper point out that the pre-Cambrian basement in the area is composed of Paleo-core, Qiantang Arc Rising Belt and Cathaysia. Firstly, Dongan-Jinning movement cratonized the Yangtze Para-platform and the Caledonian movement ceased the developing stage of trough-platform(graben), and then transformed into the developing stage of cratonic syneclise depressions and basins. In this paper, the characteristics of Late Paleozoic protobasins are described in detail.The structure zones are classified and divided into three developing stages, depending on the structure evolution history,i.e. faultdown, depression and transformation stages. Indosinian-Early Yenshan movement is a major event which reworked the Late Paleozoic basins and resulted the intraplate deformation of severe foldings and nappings, trending from southeast to northwest in the Paleozoic sequences. The deformation pattern mainly is basement decoupling and the foredeep depressions formed at fore-nappings. Such a movement reworked Late Paleozoic intra-plate depression,and superposed and preserved the depression as well.All of these mentioned undoubtedly would provide favourable conditions for the Paleozoic oil/gas generation and accumulation and in addition, the petroli-ferous prospects in Meso-Cenozoic foredeep depression also can not be ignored.

https://doi.org/10.11781/sysydz198703272