【作者】 赵长煜；

【导师】 钱荣毅； 宋海斌；

【作者基本信息】 中国地质大学（北京） ， 地球探测与信息技术， 2009， 硕士

【摘要】 目前国内盆地的构造-热演化模拟研究多集中在中国东部的裂谷盆地,对于江汉盆地这样一个在前震旦系陆壳基底上,经历了多期升降、拉张、挤压构造活动作用,最终形成的多期原型盆地并列迭加的叠合盆地,构造—热演化模拟工作开展的不多。对于江汉盆地的热历史研究,多集中在对新生代伸展断陷盆地的研究,并且热历史研究的方法多采用古温标法。利用地球动力学方法进行构造热演化模拟研究,可以帮助我们从更深、更广的岩石圈角度和尺度来研究沉积盆地的热历史,探索深部动力作用和构造活动与快速沉积、剥蚀等浅部作用相结合的方法,模拟研究盆地的热体制。本文尝试从盆地的构造-热体制出发,基于地球动力学理论,对江汉盆地的宜随、监应、临黄、宜洪四条地质剖面进行了构造模拟。晚印支期—中燕山期,江汉盆地受到了强烈的挤压改造,模拟结果表明,江汉盆地中部地区此时的缩短率约为23.9%。南部挤压作用更为强烈,缩短率25.9%。燕山晚期以后,全区进入伸展构造环境,江汉盆地广泛接受了白垩系、古近系、新近系沉积。在构造模拟的基础上,采用应变速率法对江汉盆地进行长时间序列的构造热演化模拟。反演了宜随、监应和临黄剖面570Ma以来的基底热流密度。结果表明在390Ma以前,江汉盆地基底热流一直处于缓慢增长阶段,570Ma热流普遍在57mW/m2左右;390～240Ma,江汉盆地中部热流进入衰减期,240Ma热流普遍降至55W/m2左右;240～159Ma,热流迅速升高,盆地北部部分地区甚至达到了历史极大值,整个盆地的热流分布呈现“北高南低”的分布特征,随后江汉盆地的热流变化出现明显的区域特征,部分区域热流变化较为复杂。最后计算了三条剖面的各期的温度场,实现岩石圈尺度的热模拟与盆地尺度的热模拟的有机结合。建立的多期挤压、伸展构造旋回沉积盆地的构造热演化模拟流程,为中国陆域前新生代海相沉积盆地的热历史研究提供了新的思路。更多还原

【Abstract】 Currently, most of the tectonic- thermal evolution researches for sedimentary basins in China are focused on the rift basins in the east of China. Jianghan basin is a superposed basin formed by multiple extensional and compressional tectonic deformation on Pre-Sinian crystallized continental crust. The researches of tectonic-thermal evolution of Jianghan basin are few,and most of them are focused on Cenozoic extensional rift basin stage, or used palaeo-temperature indicator method.Tectonic-thermal evolution modeling, witch are based on geodynamics, is useful to study the thermal history of sedimentary basins based on the thermal structure of the Lithosphere scale. The method can combine the effects of deep-dynamics, the tectonic activity, rapid sedimentation and erosion, etc.In this paper, tectonic modeling of four geological profiles (Yihong , Yisui , Jianying , Linhuang) in Jianghan Basin were carried out based on geodynamics setting. From late Indo-Chinese epoch to mid-Yanshanian epoch,Jianghan basin was deformed intensively by compressional tectonic activity. The shortening rate was 23.9% in the central region, and 25.9% in the south. After late-Yanshanian, Jianghan basin entered extensional period and deposited thick sedimentary strata.Long time series models of tectonic-thermal evolution about Jianghan Basin were set up by strain rate method. The basal heat flow densites and temperature fields of Yihong, Yisui, Jianying profiles were inversed for different historical stages, which are important for maturity studies of source rocks in Jianghan Basin. The results of the thermal evolution modeling showed that HF (heat flow) increased slowly before 390Ma from about 57mW/m2 at 570Ma, decreased to 55mW/m2 at 240Ma, and increased rapidly from 240Ma to 159Ma, when the heat flow achieved the historical maximum value at the northern area of JiangHan basin. Subsequently, it changed significantly and showed different regional characteristics. The method combines the thermal model of the lithosphere scale and that of the basin scale. The process flow for modeling tectonic-thermal evolution is established for multi-period extensional and compressional tectonic cycles, which provides a new way for study of the thermal history of pre-Cenozoic marine facies sedimentary basins in China.更多还原