压扭性盆地的类型与成因机制

压扭性盆地是世界上广泛发育的一类盆地,也是一种主要的含油气盆地类型.对压扭性盆地合理分类,并对每类的形成机制进行深入探讨,将有助于开展压扭性盆地油气地质综合研究与勘探前景评价.从有利于盆地构造研究与油气勘探的角度提出了压扭性盆地的分类方案.根据压扭作用发生的时间及其与所形成盆地的成因关系,可分为原生和后生压扭性盆地,然后根据盆地所处的板块构造部位、压扭作用的动力机制和压扭作用力的大小等因素,又分为许多次级类型.根据压扭性盆地的地球动力学环境,剖析了其成因机制和构造特征.压扭性盆地形成的构造环境与张(张扭)性盆地有很大不同,主要形成于斜向挤压背景,包括斜向会聚板块边界、转换板块边界和碰撞造山带的周边地区;后生压扭性盆地的成因机制比原生的更为复杂,板块之间的斜向挤压、微陆块的加入、板块的旋转等因素都可能形成压扭性盆地. 

GEODYNAMIC TYPES AND MECHANISMS OF TRANSPRESSIONAL BASINS

The transpressional basin is not only one of the widespread basin types but also an important petroliferous basin type in the world.A reasonable classification and the discussion of formation mechanism of transpressional basins will be helpful for petroleum geology study and exploration potential eva-luation.Based on the study of basin structure and hydrocarbon exploration,it is put forward in this paper a basic classification scheme of the transpressional basins.According to transpression time and its relation to basin formation,the transpressional basins can be basically classified into the proto-and the post-transpressional ones.Then,according to plate tectonic settings,transpression mechanism and transpressional force magnitude,the transpressional basins can be further classified into many secondary types.Based on the geodynamic settings of transpressional basins,it is analyzed in this paper their formation mechanisms and structural features.The tectonic background of transpressional basins is quite different from which of the extensional or trans-extensional basins.The transpressional basin has been predominantly resulted from oblique compression,such as oblique compression plate boundary,transform plate boundary and the peripheral area of collisional orogens.The formation mechanism of post-transpressional basin is much more complicated than that of the proto-transpressional basin.The oblique-compression between plates,the accretion of micro-terranes,and the plate rotation,etc.can accordingly give rise to the formation of transpressional basin.