秦岭俯冲板块前缘石炭纪构造-沉积环境

CARBONIFEROUS TECTONIC AND SEDIMENTARY SETTING OF FRONTAL MARGIN OF QINLING SUBDUCTING PLATE

石炭纪处于秦岭南、北板块由俯冲到全面碰撞的重要阶段。在俯冲板块前缘,石炭系发育在两种不同类型的沉积盆地之中。前缘南带盆地的形成与俯冲板块边缘弯曲而导致的浅层水平伸展有关,前缘北带主要为一些小型残余盆地,并明显遭受定向滑移构造的改造。两种不同沉积作用演化是在不同的构造过程中形成的。

The Qinling orogenic belt is divided by the ShangDan fault zone into northern and southern plates. Northward subduction initiated from the beginning of the palaeozoic and then was followed by arc-continental collision during the Hercynian-Indosinian periods. The Carboniferous was just the important stage of transition from subduction to collision, and the detailed tectonic and sedimentary processes were recorded by the Carboniferous strata developed in the frontal margin of subduction plate. The southern-zone basins were formed through shallow-level extension due to the bending of subducting-plate frotal margin. The northern-zone basins are believed to result from the irregularity of plate boundaries, and be positioned at ressess parts of subducting plate.