【摘要】 岩石圈热结构直接影响着岩石的物理性质和流变学性质,从而制约着岩石圈的形成演化。在研究南沙海槽前陆盆地地质构造背景和岩石圈热结构影响参数基础上,文章采用一维稳态热传导方程模拟计算并获得了盆地94N05地震剖面岩石圈热结构。计算表明,盆地区域大地热流平均值约为62mW.m 2;地幔热流值约37—44mW.m 2,对地表热流贡献达60%—70%。南沙海槽前陆盆地处于构造热恢复阶段,地表热流受中中新世挤压构造环境影响相对较低且主要受深部地幔控制,莫霍面温度介于500—600℃,热岩石圈较薄,厚度约60—70km。通过计算岩石圈热结构及居里面深度特征揭示揭示盆地深部岩石圈温度较高以及热活动稳定可能是南沙群岛海域地震发生很少的重要原因。更多还原

【Abstract】 Thermal structure of continental lithosphere can directly affect physical and rheological properties of rock,thus limiting the evolution of lithosphere.Based on tectonic setting and influencing parameters of lithospheric thermal state in the Nansha Trough Foreland,we numerically simulated lithospheric thermal structure of 94N05 seismic profile in the basin using an one-dimensional steady-state heat-conduction equation.Simulation Results show that average heat flow is about 62 mW·m 2 in the basin,and mantle heat flow is between 37 and 44 mW·m 2,which is up to 60% 70% of the surface heat flow. The Nansha Trough Foreland Basin is in the tectonic thermal recovering phase.Affected by compressional tectonic surroundings since the Miocene,the surface heat flow is relatively low and mainly controlled by deep mantle,and temperature of Moho varies from 500 to 600℃.Thickness of thermal lithosphere is as thin as 60 70 km.This research also reveals that key factors of few regional earthquakes may be related to high temperature and thermal stabilization of the deep lithosphere in the Nansha Islands waters.更多还原