四川省大地构造单元划分及其基本特征

Divisions and their basic characteristics of tectonic units in Sichuan Province

四川省大地构造演化研究已有百余年的历史,不同时期、不同学派在不同的尺度上提出了不同的大地构造单元划分方案,其中仍存在诸多争议。本文结合近30年来四川省特别是造山带地区开展的蛇绿岩和洋板块地层等调查和研究成果,以李廷栋所提出的洋板块地质学理念为指导思想,以区域主构造事件形成的优势大地构造相的时空结构组合和存在状态为基本原则,划分出秦-祁-昆造山系、勉县-略阳对接带、北羌塘-三江造山系以及扬子克拉通4个一级构造单元,包括11个二级构造单元和24个三级构造单元。

Researches on tectonic evolution about Sichuan Province have had a history more than 100 years. Different divisions of geotectonic units have been put forward by different schools in different periods at different scales. This study is combined with the survey of ophiolite and oceanic plate stratigraphy in the orogenic belt area of Sichuan Province in the past 30 years. The concept of oceanic plate geology proposed by academician Li Tingdong is taken as the guiding ideology, and the basic principle is the space-time structure composition and existence state of dominant geotectonic facies formed by major tectonic events in specific regions.It is suggested that Sichuan Province should be divided into 4 first-order tectonic units i.e. the Qin-Qi-Kun orogenic system, Mianxian-Lueyang abutting subduction zone Sanjiang orogenic system and Yangtze craton, including 11 second-order tectonic units and 24 third-order tectonic units.