摘要
研究软流圈物质运动及其对断陷盆地运动特征的影响,是揭示软流圈与岩石圈相互作用,认识华北克拉通破坏的深部动力学过程的基础.本文以鄂尔多斯块体周缘断陷盆地为研究对象,利用数值方法模拟了盆地底部软流圈物质的运动,进而分析了软流圈物质运动对周缘断陷盆地运动特征的影响.研究结果表明:(1)软流圈物质水平运动的区域流向为NWW-SEE向,流速基本一致,局部略有变化.随着深度增加,局部变化特征不再显著;(2)软流圈物质垂向运动存在区域性差异,其中鄂尔多斯体块体北部、西部以及北缘、西缘底部,物质以下沉流为主,尤其西缘下沉流更显著;块体中部、东部以及南缘、西南缘底部,以上升流为主;东缘底部,上升流与下沉流相间分布,以上升流为主.随着深度增加,上述区域性差异特征依然明显;(3)依据热物质的水平拖曳和垂向拉张作用对断陷盆地可能产生的影响,进一步推测,软流圈物质运动有利于北缘盆地的剪切走滑,东缘盆地的伸展拉张,南缘盆地的走滑兼拉张,西缘和西南缘盆地的走滑.
It is important to research on movement characteristics o{ asthenosphere material and its effect on the movement characteristics of fault basins. Based on this study, we can reveal the interaction between asthenosphere and lithosphere, and analyze dynamic process of destruction of the North China Craton. Taking the fault basins surrounding the Ordos block as the study object, we simulated the movement of asthenosphere material beneath the basins, and discussed the effect of the movement of asthenosphere material on the movement characteristics of fault basins. The results showed that： （1） the horizontal movement direction of the asthenosphere material was NWW-SEE; the horizontal movement rate changed little, except for some local slight changes which decreased with depth. （2） There were differences in the vertical movement of the asthenosphere material. There was downwelling beneath the northern and western part, including the northern margin and western margin of Ordos. While there was upwelling beneath the central and eastern part, as well as the southern margin and southwest margin of Ordos. The upwelling and downwelling are alternately distributed beneath the eastern margin, and the upwelling is the main vertical movement. The differences in the vertical motion are still significant as the depth increases. （3） According to the effect of the drag and extension induced by asthenosphere material movement on the fault basins, it was in{erred that the movement of the asthenosphere material could contribute to the sheared sliding of the fault basins in northern margin, the extension of the fault basins in eastern margin,the sliding and extension of the fault basins in southern margin and the sliding of the faults in western and southwestern margin.
出处
《地球物理学报》
SCIE
EI
CAS
CSCD
北大核心
2017年第7期2614-2627,共14页
Chinese Journal of Geophysics
基金
中央高校基本科研业务项目(ZY20120203)
地震行业科研专项项目(201208009)
国家自然科学基金青年科学基金项目(41602274)资助
关键词
软流圈
运动特征
断陷盆地
鄂尔多斯块体周缘
Asthenosphere
Movement characteristics
Fault basin
Ordos block and its margin
