惠州凹陷古近系恩平组层序地层划分及展布特征

Sequence stratigraphy and distribution of Palaeogene Enping Formation in Huizhou depression

过去对惠州凹陷古近系的层序地层研究是以二级层序为基本单元。运用构造-层序地层学理论,在惠州凹陷古近系恩平组中识别出了SB5、SB6两个三级层序界面,将恩平组划分为SQ4、SQ5、SQ6等3个三级层序,并建立了各个旋回层序的构型样式。惠州凹陷古近系恩平组沉积主要为冲积河流沉积体系、三角洲体系、扇三角洲体系、沼泽体系及湖泊体系。本文对其展布特征进行了分析,指出惠州凹陷恩平组多物源特征明显,物源方向以西部与北部为主。

The second-order sequence was used as a basic unit in earlier studies of Paleogene sequence stratigraphy in Huizhou depression. By using a theory of tectonic-sequence stratigraphy, two boundaries of third-order sequences （SB5 and SB6） are identified in the depression, and Enping For mation can be divided into three third-order sequences （SQ4, SQ5 and SQ6）, establishing the architecture style for each cyclic stratigraphic se quenee. The deposition of Enping Formation in Huizhou depression is predominated by alluvial river system, delta system, fan delta system, marsh system and lake system, and their distributions are analyzed in the paper, indicating significant multiple provenances and west-predominated and northpredominated provenances.