二连盆地乌尼特坳陷伸展构造特征及成盆演化
Extensional structures and basin evolution of the Wunite depression in Erlian Basin
-
摘要: 乌尼特坳陷属于二连盆地五大坳陷之一，早白垩世在区域引张力下形成一系列地堑、半地堑，其伸展构造由伸展断层及变换构造组成。伸展断层中的主边界断层主要为铲式，混杂岩断陷带主边界断层多在混杂岩深层滑脱，复式向斜断陷带主边界断层多在浅层滑脱。平面上主边界断层表现为简单弧形或波状延伸，位移量通过变换断层及走向斜坡等进行调节/传递。首尾相连的断陷间主要以狭窄的背向型（divergent）及宽阔的相向型（convergent）变换带进行构造变换，穿过变换带断陷极性常常发生变化。早白垩世早期，乌尼特坳陷由多个相互独立的小型断陷组成；早白垩世中期，随着伸展量不断加大，相邻断陷边界断层逐渐侧向连接成为区域性边界断层，相邻断陷侧向连接成为大型复式断陷；早白垩世晚期，断陷群下沉坳陷进入后裂陷期。Abstract: The Wunite depression is one of the five depressions in the Erlian Basin. A series of grabens/half grabens were developed under the action of regional extension in Early Cretaceous. Extensional fault and transform structure form the extensional structures. The major boundary faults (MBF) are listric faults, slipping deep in the mélange zone and being shallow in complex synclines. The MBF extends like a simple arc or a wave. Accommodating/propagating displacement is realized through transfer fault or strike ramp. Divergent TZ and convergent are the main transfer structures between faulted-sags. And the MBF tendency often changes through the divergent or convergent TZ. In the early Early Cretaceous, lots of independent small-scale faulted-sags filled Wunite Depression; in middle Early Cretaceous, with the continuing of extension, adjacent faults were laterally propagating to become the regional boundary fault and adjacent faulted-sags were connected to become the complex faulted-sag; in late Early Cretaceous, the depression entered into the post-rifting stage.
-
Key words:
- extensional structures /
- basin evolution /
- Wunite depression /
- Erlian Basin.
-
-
计量
- 文章访问数: 1968
- PDF下载数: 1386
- 施引文献: 0
下载: