摘要
依据 10口系统测温井数据和 6 1块岩石热导率测试结果 ,计算了辽河盆地东部凹陷 10个高质量的大地热流数据 ,并在此基础上 ,利用镜质体反射率 (Ro)资料对该区的热历史进行了恢复 .结果表明 :东部凹陷下第三系平均地温梯度为 36 .5℃ km ,岩石平均热导率为 1.6 6 7W (m·K) ,热流密度变化于 49.5～ 70 .0mW m2 之间 ,平均为5 8.0mW m2 ;东部凹陷热流呈现古热流高现今热流低的变化特征 ,从沙三期到东营期 ,古热流值是逐渐增大的 ,到东营期末达到最大值 ,晚第三纪至现今表现为持续冷却 ;构造沉降史分析显示 ,盆地经历了早期的裂谷阶段 ( 43～2 5Ma)和后期的热沉降阶段 .盆地现今较低的大地热流和较高的古热流及典型的裂谷型构造沉降样式为东部凹陷的构造 -热演化提供了重要认识 .
Based on temperature measurements in 10 boreholes and thermal conductivity determination of 61 rock samples, 10 heat flow values were obtained for the eastern subdepression of Liaohe basin. The thermal history of eastern subdepression was reconstructed based on the vitrinite reflectance (Ro) data. The results show that the mean geothermal gradient and thermal conductivity are about 36.5 ℃/km and 1.667 W/(m·K) respectively, and the corresponding heat flow ranges from 49.5 mW/m 2 to 70.0 mW/m 2, with a mean of 58 0 mW/m 2. The eastern subdepression experienced a much higher heat flow period from 43Ma to 25Ma. After reaching the maximum heat flow of～82 mW/m 2 at 25Ma, the subdepression cooled down to the present-day heat flow of ～60 mW/m 2. Structural subsidence analysis shows that the subsidence of eastern subdepression is divided into two phases: earlier syn-rift phase (25～43Ma) and late thermal subsidence phase (since 25Ma).The lower present-day heat flow and the higher palaeo-heat flow corresponding to structual subsidence stages as well as the typical rift subsidence style provide some insight into the tectonothermal evolution of the basin.
出处
《地球物理学报》
SCIE
EI
CAS
CSCD
北大核心
2003年第2期197-202,共6页
Chinese Journal of Geophysics
基金
国家自然科学基金项目 (40 1 72 1 0 0 ) .
关键词
辽河盆地
东部凹陷
大地热流
热史恢复
构造-热演化
Liaohe basin, Eastern subdepression, Heat flow, Thermal history, Tectonothermal evolution.
