南沙板内新生代沉积基底构造特征及其控盆机制

通过综合分析南沙海域地质地球物理资料,依照板块理论的层块思想,对南沙板内新生代沉积基底构造特征进行了剖析。在南沙板内划分出了南薇-安渡和礼乐-半月两套倾滑-层滑-走滑基底断裂系统及其所围限的相应的基底层块。从多元动力成因观出发,分析了南沙板内盆地的成因机制,提出中壳塑流作用是南沙板内盆地的主要成因动力。根据动力作用方式的不同,划分了南薇-安渡、费信-南华、礼乐-北巴拉望3个主要的板内盆地群。分别就南薇-安渡、礼乐-北巴拉望板内盆地群的成盆机制提出了“基底层块对向倾滑-拆离”和“基底层块单向倾滑-拆离”模式。本研究对全球构造分析和南沙海域油气资源勘查具有重要意义。

Characteristics of Cenozoic Sedimentary Basement Structures and Their Control-basin Mechanism within Nansha Micro-plate

The Characteristics of Cenozoic Sedimentary Basement Structures within Nansha micro- plate were anatomized via synthetic analysis on the geology and geophysics of Nansha Micro-plate, in the light of the layer-block thinking of plate theory. There are two basemental fault systems of "dip -sliplayer-slidestrike-slip" 4-dimensional interrelated motion of Nanwei-Andu and Reed-Banyue, and two corresponding basement layer-blocks encircled by the two systems respectively. According to the multi-geodynamic force view, a mid-crust plastic layer upheaving force was proposed as the main dynamical force causing the formation of the intralpate basins within Nansha micro-plate. The intraplate basins within Nansha micro-plate can be divided into three basin groups of Nanwei-Andu, Feixin-Nanhua, and Reed-North Balawan based on the different effect manners of the main dynamical force. Finally, the models of an opposite-dip slipdetachment of basement layer-block and a unilateral-dip slipdetachment of basement layer-block were put forward for the basin-forming mechanisms of the Nanwei-Andu and Reed-North Balawan intralpate basin groups, respectively. This study is important for the global tectonic analysis and the oil and gas perambulation of the Nansha sea area.