【摘要】 受多期非均衡造山作用以及多构造体制的叠加,东秦岭-大别造山带北侧中新生代发生差异构造变形。基于区域构造动力学机制,将中新生代构造变形分为4个期次:印支期(T2-T3)、早燕山期(J1)、中燕山期(J2-K1)和晚燕山-早喜马拉雅期(K2-E)。通过野外地质剖面和地震剖面的构造解析,认为印支期-中燕山期主体变形方式为逆冲推覆作用,变形强度自东向西发生时空迁移;晚燕山-早喜马拉雅期为关键构造变革期,发生区域伸展变形,且以信阳-合肥盆地和灵宝-鲁山-确山-固始-肥东断裂一带伸展作用最强。平衡剖面恢复显示,印支期和中燕山期为东秦岭-大别造山带北侧两期主要逆冲推覆构造发育期,其中印支期强烈的逆冲推覆作用发生于商城-潢川一带以东,而中燕山期则发生于商城-潢川一带以西。中燕山晚期(K1),受差异造山作用,研究区东西构造变形分异,东秦岭北侧发生强烈收缩变形,而大别北侧则在热隆作用下发生滑覆。更多还原

【Abstract】 Because of the multiphasic unbalanced orogeny and superimpose of multiple tectonic system,there is Meso-Cenozoic differential deformation in the northern East Qinling-Dabie orogenic belt. Based on the difference in geodynamic mechanism, the Meso-Cenozoic tectonic deformation in the northern East Qinling-Dabie Orogenic Belt could be divided into four epochs including Indosinian (T2-T3), Early Yanshanian (J1), Middle Yanshanian (J2-K1), Late Yanshanian -Early Himalayaian (K2-E). Structural analysis of two petrofabric sections and three seismic ones show that the tectonic deformation mode was thrusting from Indosinian to Middle Yanshanian, and the deformation strength had a feature of space-time migration from east to west. Late Yanshanian-Early Himalayaian was the key tectonic transform epoch in which the deformation was extensional,and the strongest extensional deformation happened in Xinyang-Hefei basin and the area along the Lingbao-Lushan-Queshan-Gushi-Feidong fault. And in order to understand the deformation strength from space-time, three balance cross-section were finished. The data display that Indosinian and Middle Yanshanian are the major epochs of thrusting in the northern East Qinling-Dabie orogenic belt. The intense thrusting lied in the east of the Shangcheng-Huangchuan area in Indosinian, and west in Middle Yanshanian. Because of the varying orogeny, the tectonic deformation was differential from the east to west of the study region in late Middle Yanshanian(K1). The deformation was thrusting in the northern East Qinling orogenic belt, and slumped overthrusting in the northern Dabie owing to thermal doming.更多还原