摘要
本文将东祁连逆冲带与鄂尔多斯西南缘晚三叠世前陆盆地相结合,研究了逆冲带内部变形特征,前陆盆地中层序地层格架特征及其反映的盆缘构造性质和幕式逆冲作用。在此基础上,建立了逆冲带与前陆盆地对耦合机制的地质模型和力学模型,并选定参数模拟了前陆盆地沉降和沉积过程。
The subsidence and deposition of the Late Triassic foreland basin on the southwestern margin of Ordos have a close genetic connection with the thrusting of the orogenic belt on both sides of the adjacent Eastern Qilian Mountains. The stratigraphic sequence of the basin preserves a re-cod of the thrusting history of the orogen. Three sequences may be distinguished in the basin; sequences 1 and 2 are the depositional response to two events of thrusting of the Liupanshan foreland fold-thrust belt on the north side of the Eastern Qilian two-side orogen, which are composed mainly of the steep-slope deltaic system and alluvial fan system against a thrusting background; sequence 3 is a depositional response to the subsidence of post-thrusting isostatic adjustment, consisting mainly of the fluvial system and lacustrine-deltaic system against depression background. The structural subsidence rates for sequences 1 and 2 increased twice, while the rate for sequence 3 decreased. The subsidence and deposition of the foreland basin resulted from a combianed ac- tion of the structural load of the zone, sedimentary load of the basin and intra-crust horizontal compression produced during the orogeny, which can be simulated by the deflection model of the broken, elastic plate applied by horizontal compression, thrust and sediment loading and isostatic restoring force using 7 parameters. Through taking the sections of the Maxia-Zhenyuan prototype basin and the northeastern thrust belt of the Beidao-Guguan large flower structure for example , the evolution of the thrust belt-foreland basin system was simulated using the computer after assigning 7 parameters of different values.
出处
《地质学报》
EI
CAS
CSCD
北大核心
1996年第1期12-22,共11页
Acta Geologica Sinica
基金
地质矿产部重要基础理论项目(编号 8502204)
国家自然科学基金(编号 48970110)
关键词
逆冲带
前陆盆地
盆地沉降
沉积过程模拟
computer simulation, subsidence, deposition, foreland basin, Ordos
