论文部分内容阅读
为了揭示盆地深水区演化及裂后期大规模沉降的成因机制,在琼东南盆地典型的、高品质地震剖面地质构造精细解释基础上,结合岩石圈变形的挠曲悬臂梁模型和挠曲均衡模型,应用正演和反演模拟技术,定量恢复了该盆地所处地区的上地壳、地壳以及岩石圈的伸展程度.结果表明,琼东南盆地自陆架边缘到深水坳陷区,岩石圈上地壳的伸展系数较小,β值最大为1.23～1.32;整个地壳的伸展系数变化较大,盆地边缘隆起区的β值在1.1～1.2之间,向盆地中部β值逐渐增大到3.14;而对整个岩石圈而言,其伸展系数β值由陆架到陆坡深水盆地也从1.2逐渐增大到4.2.根据对南海地区的构造及岩石圈和地壳的结构分析认为,与McKenzie的岩石圈均一伸展以及由热控制的裂后期缓慢沉降过程不同的是,上述与深度相关的岩石圈伸展减薄是由南海西北次海盆扩张过程中深部物质的离散上涌流动所导致的下地壳的快速而强烈的塑性流动所引起的,并由此建立了琼东南盆地的形成演化模式,来解释和探讨深水坳陷区及裂后期快速而大规模沉降的成因机制.
In order to reveal the genetic mechanism of deep-water area evolution and large-scale subsidence during the late Cretaceous, based on the fine interpretation of the typical high-quality seismic sections in the Qiongdongnan Basin and the flexural cantilever model and deflection equilibrium model of lithosphere deformation, The application of forward modeling and inversion modeling quantitatively restored the extensibility of the upper crust, crust and lithosphere in the area where the basin was located.The results show that the extension of crust on the lithosphere from Qiongdongnan basin to the deepwater depression The coefficient is small, the maximum value of β is 1.23-1.32; the coefficient of extensibility of the whole crust varies greatly. The β value in the uplift of the basin edge ranges from 1.1 to 1.2 and gradually increases to 3.14 in the central part of the basin; In terms of the structure of the South China Sea and the structural analysis of the lithosphere and the crust, it is believed that the extension of the extension coefficient β from McKenzie to the lithosphere of the McKenzie, and from the heat Controlled post-split slow subsidence process is different from the depth-related lithospheric extension is thinning by the South China Sea sub-sea basin during the expansion of the deep material discrete upflow Fast and strong plastic flow in the lower crust caused caused, and thus established a pattern formation and evolution of the southeast Qiong basin, to explain and explore the rapid and large-scale settlement of the genetic mechanism of the deep water area and post-split depression.