江汉平原区中、古生界构造特征及演化

Tectonic Features and Evolution of Mesozoic-Paleozoic in Jianghan Plain Region

印支期以来江汉平原区经历了多期构造运动的叠加和改造,中、古生界的构造特征总体以南北造山对冲挤压为特点,形成南部受控于雪峰-江南造山带的八面山-大磨山弧形构造带和北部受控于东秦岭-大别造山带的大洪山弧形构造带两大弧形构造体系,且以南部弧形构造带为主体。早燕山期是弧形构造的主要发育期,南部弧形构造带首先形成雏形,前缘断裂为问安寺-纪山寺-潜北-天门河断裂,随后秦岭-大别碰撞造山,产生自北东向南西的挤压应力,北部大洪山弧形构造带开始发育,并对南部弧形构造带产生叠加和改造作用,在荆州-大冶地区形成对冲干涉构造带;晚燕山-早喜山期,构造负反转,荆州-沔阳地区强烈断陷,使得对冲干涉构造带隐伏于江汉盆地白垩-新近系之下,成为隐伏前锋构造。多期次的构造作用,使研究区发育挤压收缩构造、走滑压扭构造及伸展反转构造三大类基本构造样式。

The marine Mesozoic-Paleozoic in Jianghan plain has experienced multi-period deformations and superpositions since Indochina period, resulting in a counter-thrust and compress tectonic framework with S to N thrust in the south and NE to NW thrust in the north. The two great arc structure systems are thus formed： the Bamianshan-Damoshan arc structure located in the south, and the Dahongshan arc structure located in the north. The former is a main structure, whose formation and evolution are mostly controlled by the Xuefeng-Jiangnan orogenic belt, while the latter is mostly controlled by east Qinling-Dabie orogenic belt. The two systems were mainly developed and shaped in early Yanshanian, when the south arc structure embryo was formed with its front-fault as Wenansi-Jishansi-Qianbei-Tianmenhe fault before the north arc structure which was developed in the compress stress field from NE to NW due to the orogenics of east Qinling-Dabie orogenic belt,and reformed the south arc structure. Both of them are connected composited in Jingzhou-Mianyang region in the middle of Jianghan plain,resulting in a counter-thrust and interference structural belt. The Jingzhou-Mianyang interference belt was buried under Cretaceous-Paleogene stratum of Jianghan basin during the late Yanshanian period to early Himalayan period for the reason of tectonic negative reversion, and became buried front structure.