地质学报2025，Vol.99Issue(5)：1807-1818,12.DOI:10.19762/j.cnki.dizhixuebao.2023459
数值模拟揭示深部热力学结构对大陆裂解过程的控制作用
Numerical simulations reveal the control of deep thermal-mechanical structure on continental breakup process
摘要
Abstract
The formation and evolution of passive continental margins are controlled by the vertical thermal-mechanical structure of pre-rifting lithosphere.In order to investigate its effect on lithospheric breakup time,faulting styles,sizes and morphology of passive continental margins,we define 3 comprehensive indexes as accumulated lithospheric yield stress(σe),average yield stress((-σ)t)and crust-mantle rigid layers coupling degree(Coc),and reveal the influences through geodynamic numerical modelling.According to simulations,the thermal-mechanical structure of lithosphere plays a key role in controlling its rifting duration,a stronger pre-rifting lithosphere inevitably causes a longer lasting rifting,and on this basis,the decrease of the Coc will prolong this process.For the fully coupled lithosphere(Coc=1),upper crust usually breaks first,and will form symmetric margins through a 'pure-shear' mode.When Coc decreases,rigid layers of upper crust and upper mantle deforms separately,and an asymmetric continental margin will form by lateral migration of the rift center.Under such circumstances,the upper mantle with a relatively limited thickness will break first,while when a thick upper mantle develops,the upper crust will break first and lead to the exhumation of mantle rocks.In addition,a low Coc is necessary to generate large-scale passive continental margin basins with a broad and gentle geometry,and the lower Coc is,the greater the migration distance of the rift center and the conjugated margins are.Thickening of the crust will lead to the decreasing of Coc,which will also enlarge the scale of continental margins.Those understandings can be verified on the central segment of South Atlantic continental margins.关键词
热力学结构/耦合程度/被动大陆边缘/数值模拟Key words
thermal-mechanical structure/coupling degree/passive continental margin/numerical modelling引用本文复制引用
范庆凯,郭金瑞,高敏,吴高奎,王炎阳..数值模拟揭示深部热力学结构对大陆裂解过程的控制作用[J].地质学报,2025,99(5):1807-1818,12.基金项目
本文为中国石化基础前瞻项目(编号P22214-2,P22214-1)资助的成果. （编号P22214-2,P22214-1）
