塔北中、新生代前陆盆地沉降机制的数值模拟

NUMERICAL MODELING OF SUBSIDENCE MECHANISM OF A MESO-CENOZOIC FORELAND BASIN IN NORTH TARIM

曹守连 陈发景 罗传容

Cao Shoulian Chen Fajing Luo Chuanrong

大陆岩石图对造山带的挠曲响应是前陆盆地的构造沉降机制.中、新生代时,塔里木盆地北部地区进入前陆盆地发展阶段.本文通过数值模拟的方法探讨了塔北地区的沉降机制,模拟的结果表明,弹性模型基本上能够较好地解释塔北地区自晚二叠世以来的沉降机理.

A typical foreland basin developed in the northern part of Tarim after Hercynian.The basin was firstly confined to the piedmont of South Tianshan during TriassicJurassic, then extended southward and covered a large area since Cretuceous. The purposeof this paper is attempting to discuss the subsidence mechanism of the basin through numerical modellins. Assuming the continental lithosphere of the area to be a uniform elasticplate, tubing Tianshan orogenic zone as tectonic loads, strata distribution modelling wasmade in five stages. The main parameters necessary for the modelling included obeervedstructural sections, fie-cural rigidity of the lithosphere and the amounts of tectonic loads.The results of the modetling are theoretic structural sections and topography of specifiedload feature. Finite element method was used to solve the fie-cure equation during themodelling process. The theoretical subsidence Plofiles show considerable fit with theobserved tectonic sections except some differences in Shaya uplitf. This indicates that thefie-cural respond of the lithosphere to Tianshan mountain loads may be used to explain themain subsidence mechanism of the basin. The parameters acquired through modelling areanalogous to some typical foreland basin during Meso-Cenozoic.

10.11743/ogg19940202