层序地层作为沉积盆地识别标志的研究

SEQUENCE STRATIGRAPHY APPLIED TO THE IDENTIFICATION OF SEDIMANTARY BASIN

本文以盆地充填动力学为指导 ,从层序界面与盆山转换、层序级别与盆地规模、层序格架与盆地类型、层序充填与盆地演化 4个方面 ,对层序与盆地的关系进行了初步研究 ,结果表明层序地层作为盆地的识别标志主要包括 :①不同成因类型和规模级别的界面作为划分相应成因级别层序的重要标志 ,它们反映地壳演化过程中的动力转换事件 ,其中超级、Ⅰ级、Ⅱ级界面分别反映盆地域之间、盆地之间、盆山之间的应力转换机制 ,Ⅲ—Ⅳ级界面揭示了构造、海平面、气候、物源联合引起的盆地容纳空间和沉积机制的转变过程。②作为板间、板缘、板内过程的沉积记录 ,层序与盆地之间存在特定的耦合关系 ,即超级层序相当于沉积盆地域 ,Ⅰ级层序相当于沉积盆地 ,Ⅱ级层序对应于盆地构造沉积幕 ,Ⅲ级层序对应于盆地充填幕 ,Ⅳ—Ⅴ级层序相当于盆地充填韵律。③不同成因沉积盆地 ,层序成因格架及内部构型各异 ,因而根据层序特征研究 ,可判识盆地成因属性。④在盆地演化的不同阶段 ,盆地性质、构造特征、沉积格局存在差异 ,所形成的层序构型、界面属性及组合特征等亦不同 ,因而通过层序充填序列的研究 ,可揭示盆地演化过程。

In the light of sequence basin geosystem theory in conjunction with previous results, the relationship between sequence and basin has been tentatively studied,including the following:1) sequence boundaries and basin mountain transformation,2) sequence hierarchies and basin scales,3) sequence genetic frameworks and basin types, and 4) sequence filling successions and basin evolution. Several relationships between sequence stratigraphic frameworks and the basin natures have been discussed:1) Different hierarchies and genesis of sequence boundaries reflect the dynamic transformation of sedimentary basin, in which super order, first order, second order boundaries indicate the stress mechanisms of the basin tract basin tract, basin basin, and basin mountain transformation, the third order and fourth order boundaries reflect the transformation process of accommodation and sedimentation mechanisms.2) Different hierarchies of sequences show a certain intrinsic coupling relationships with sedimentary basins. The super order sequence corresponds to the sedimentary basin tract. The first order sequence corresponds to the sedimentary basin. The second order sequence corresponds to the basin tectonic stage. The third order sequence corresponds to the basin infilling episode. The fourth order and fifth order sequences correspond to the basin filling rhythms.3) Sequence characteristics, such as boundary nature, sequence geometry, structure, scale, thickness, completeness and symmetry,etc., are various in different genetic basins. Therefore, sedimentary basin can be identified on the basis of sequence genetic framework and internal architecture.4) The nature, structure and sedimentary framework of basins are different during various stages of basin evolution, which results in the differences in the architectures of sequence sets, and the boundary attributes, and their combination characteristics. Therefore, the tectonic stage and evolution history of the sedimentary basin can be distinguished based on the combined characteristics, composition, architecture, and infilling pattern of sequence sets.