中国东北漠河盆地的构造背景和地质演化

在概述漠河盆地上侏罗统沉积特征及相变的基础上,基于多种证据,首次提出晚侏罗世漠河盆地是蒙古-鄂霍次克洋消减时因古缝合线活化而引起的燕山期陆内造山运动控制发育的磨拉石盆地。分3个阶段重塑了盆地发育,指出其动态演化以向北迁移为特点。侏罗纪末,随陆-陆碰撞的发生,漠河盆地闭合并经受了WE走向的冲断活动的改造(主变形幕)。白垩纪—新生代的两期改造分别以近NNE走向的张扭性断层和近WE走向的正断层为构造形迹,前者中至少可辨认出3幕变形。就油气勘探的前景而言,盆地的中-东段较西段有利,盆地的中-南部较北部有利。

Tectonic setting and geological evolution of Mohe basin in Northeast China

Based on the sedimentary features and facies change of the Upper Jurassic in Mohe basin and supported by many other evidences,it is proposed for the first time that the late Jurassic Mohe basin is a molasse basin controlled by the Yanshanian intracontinental orogeny,which was caused by the activation of the fossil suture zones related to subduction of the Mongolia-Ochotsk ocean.Three stages of the development of the basin have been established and the northward migration feature of its dynamic evolution has been identified.At the end of Jurassic the basin closed and was reformed by the W-E trending thrusts(the main deformation episode) along with continent-continent collision.From the Cretaceous to the Eogene,two phases of reformation happened in the basin and their structure features are nearly NNE trending transtentional faults,with at least three deformation episodes recognized and W-E trending normal faults.In terms of oil and gas exploration potential,the central,eastern,and southern part of the basin are more promising than the rest parts of the basin.