中中新世以来南沙海槽前陆盆地演化模拟  

NUMERICAL SIMULATION OF FORELAND BASIN EVOLUTION IN NANSHA TROUGH SINCE MIDDLE MIOCENE

作　　者：马辉[1,2] 许鹤华[1] 吴世敏[3] 刘海龄[1] 

机构地区：[1]中国科学院边缘海地质重点实验室,南海海洋研究所,广州510301 [2]中国科学院研究生院,北京100049 [3]中山大学地球科学系,广州510275

出　　处：《海洋地质与第四纪地质》2011年第6期157-166,共10页Marine Geology & Quaternary Geology

基　　金：中国科学院知识创新工程重要方向项目(KZCX2-YW-Q05-04);中国科学院南海海洋研究所知识创新工程领域前沿项目(LYQY200704);国家重点基础研究发展规划项目(2007CB41170405);国家高技术研究发展计划课题(2008AA09Z306);国家自然科学基金项目(40576025)

摘　　要：为了理解南沙海槽前陆盆地演化过程及其动力学特征,基于中科院南海海洋研究所过去数十年获得的地球物理数据和最新国内外研究成果,在深入分析盆地构造史、沉积特征等之后,建立了中中新世以来南沙海槽前陆盆地弹性岩石圈板挠曲模型,并采用有限差分数值方法来模拟盆地演化。通过模拟重建了盆地沉积沉降、构造活动、挠曲变形动态演化过程,预测了不同演化阶段盆地的几何形态、重力异常、沉积厚度等结果。模拟实验预测的0Ma阶段重力异常和盆地地形与实测数据拟合良好;同时模拟结果显示南沙海槽前陆盆地由构造沉积负载造成的最大盆地挠曲仅约2 300m,结合地质资料表明区域地壳在前陆盆地形成之前已经挠曲,且盆地挠曲可能受深部岩石圈负载作用。In order to better understand the mechanism and characteristic of foreland basin evolution in the NanSha trough, we studied the structure, sedimentology and other characteristics of the basin based on the geophysical data of the past decades collected from South China Sea Institute and recent research progress both at home and abroad. An elastic lithospheric plate flexure model for Nansha Trough foreland basin is established. The finite difference method was used to simulate the basin evolution since Middle Miocene. With the model, we reconstructed the history of deposition, subsidence, tectonic movement and deflection and deformation process in the basin, and predicted the geometry, gravity anomaly, sediment thickness of the basin in different stages. The predicted gravity anomaly and basin topography fit well with the meas ured data at 0 Ma stage. And the basin simulation shows that basin deflection caused by the sediment load is only about 2 300 m, indicating that the basin crust had been flexible before the formation of foreland basin, and the flexural deformation of the foreland basin is not only related to basin structure, topography and depositional load, but also possibly affected by lithospheric load in the deeper part.

关 键 词：前陆盆地 形成演化 数值模拟 中中新世 南沙海槽 

分 类 号：P786.1[天文地球—海洋科学]