似新华夏式伸展盆海系的基本特征及其形成演化的力学机制

BASIC FEATURES AND FORMATION MECHANISM OF PARANEOCATHAYSIAN EXTENSIONAL BASINS SYSTEM

晚中生代 (白垩纪 )以来 ,中国东部及西太平洋大陆边缘发育一系列NNE、NE乃至NEE向 (与纬向构造联合 )的巨型右行张扭性断陷 (地堑、半地堑 )在平面上组成平行雁列的多字型构造 ,其深部发育同走向的上地幔隆起和基底拆离 ,地表常出现变质核杂岩和大型低缓倾角的伸展剥离断层 ,它主要是东亚及西太平洋大陆边缘陆缘扩张的产物 ,其地球动力学过程为晚燕山期以来的后造山期的大陆隆升和水平侧向伸展以及晚白垩世末一早第三纪、45Ma以来的印度板块与欧亚板块碰撞所产生的碰撞效应。

There develop a series of dextral transtesoinal fault basins (graben and half graben) trending NNE since the late Mesozoic (Cretaceous period) in the continental margin of East China and West Pacific Ocean. These basins were arranged as zigzag pattern in the plane view. Under these fault basins develop upper mantle uplifting and basement detachments of the same trend. Some times expressed as metamorphic core complex and big low angle extensional detachments. The regional tectonic stress field has been in horizontal extension of NW—SE direction during post orogenic period since the late Yanshannian stage. It is continental margin expanding caused by the de rooting of lithosphere (since the late Cretaceous)and the effect of the collision between India and Eurasia plates (since the end of Late Cretaceous and Early Tertiary period).