安徽沿江地区中晚三叠世沉积演化及其与印支早期金子运动关系的探讨

Discussions on the relationship between the Middle-Late Triassic sedimentary evolution and the early Indosinian Jinzi movement along the Yangtze River area in Anhui

关键词:  角砾岩  岩相古地理  金子运动  中晚三叠世  安徽沿江地区

Key words:  breccias  sedimentary facies and palaeogeography  Jinzi movement  Middle-Late Triassic  Yangtze River area in Anhui

摘要:

安徽沿江地区古生代-中生代地层发育较为完整,印支构造变形表现最为强烈。印支晚期南象运动已成为公认的事实,而早期金子运动存在与否及其地质界面一直存在较大的争议。本文通过关键界面的考查、角砾岩特征及成因,以及岩相古地理的演化的分析,初步认为安徽沿江地区印支运动早期金子运动确实存在,其构造界面位于周冲村组与黄马青组之间,以平行不整合或微角度不整合接触关系为表现形式,其构造样式以构造抬升为主,盆地边界以宽缓的褶皱变形为辅。该运动与南象运动(大规模的褶皱造山)共同控制了沿江地区构造格架的形成和发展。

Abstract:

The Palaozoic and Mesozoic strata are well developed and the geological structures are highly deformed along the Yangtze River area in Anhui. It is widely accepted that there occurred the Nanxiang movement during the late Indosinian, but whether or not the Jinzi movement existed during the early Indosinian is an open question. On the basis of key boundaries, breccias origin and sedimentary facies and palaeogeographic analysis, the authors in the present paper contend that the Jinzi movement took place indeed during the early Indosinian, and is manifested in the structural boundary between the Zhouchongcun Formation and Huangmaqing Formation with a parallel unconformity or slightly angular unconformity. The tectonic patterns are dominated by tectonic uplifting, and the basin boundary is embodied by board folds and deformational processes. Together with the Nanxiang movement, a large-scale folding and mountain building movement, the Jinzi movement has controlled the formation and development of the tectonic framework of the Yangtze River area in Anhui.