过渡动力学背景下的张扭性断陷——以珠江口盆地惠州凹陷古近纪断陷为例

ANALYSIS OF TENSE-SHEARING CHARACTERISTICS OF HUIZHOU PALEOGENE FAULT DEPRESSION IN PEARL RIVER MOUTH BASIN

通过断陷结构、构造特征研究及与已有的物理模拟实验结果对比分析,论证了珠江口盆地惠州凹陷古近纪断陷具有典型的张扭性断陷性质,表现为其具有典型的斜列式结构特征,构成断陷的基本要素(如断陷内的洼陷、低凸起、边界断层等)均呈斜列式展布。推测其形成机制主要受主伸展应力方向与基底构造走向斜交控制,从而沿断陷走向产生走滑分量,进而使断陷具有张扭性特征。

Tense-shearing characters of the Huizhou Paleogene Fault Depression in the Pearl River Mouth Basin has been proved by analyses of rift construction, tectonic characteristics and comparing with physical simulation results. Sub-sags, low uplifts and faults are usually en echelon-distributed in the Huizhou Paleogene Fault Depression, which is the typical character of tense-shearing rift. It is mainly formed by oblique intersecting between principal extensional stress and base structural strike. When principal extensional stress is oblique with base structural strike, strike-slipping is produced and tenseshearing characters of fault basin are formed.