二连盆地乌尼特坳陷早白垩世构造特征——深部构造与浅部构造的关联

Early Cretaceous structural feature of the Wunite depression in Erlian Basin:A connection between deep-level and shallow-level structures

乌尼特坳陷属于二连盆地五大坳陷之一,内部发育一系列地堑、半地堑,主要充填地层为下白垩统。坳陷基底由晚古生代复式向斜及二连-贺根山混杂岩带(Pz_2)组成。乌尼特坳陷早白垩世断陷结构和分布组合与基底构造紧密相关。复式向斜断陷带基底为北东向、北北东向晚古生代复式向斜,受基底控制早白垩世发育一系列北东向、北北东向断陷。断陷带北部主干断层向深部延伸时受复式向斜构造层韧性伸展变形影响而在浅层滑脱,形成浅而宽阔的断陷,主要为并联式组合。断陷带南部终止于混杂岩带并与之斜交,主干断层向深部延伸时受混杂岩带伸展走滑构造变形影响而在浅层滑脱,形成浅而狭长的断陷,主要为斜列式组合。二连-贺根山混杂岩断陷带基底为混杂岩带,受基底控制早白垩世发育一系列北东向、北北东向断陷。断陷主干断层向深部延伸时受以伸展为主的构造变形影响而在混杂岩深层滑脱,形成深而狭长的断陷,以串联或并联式组合。

The Wunite depression is one of the five depressions in the Erlian Basin. It developed a series of faulted-sags that were filled by the Lower Cretaceous. The basement is consisted of complex synclines and tectonic suture belts named the Erlian-Hegenshan m61ange zone. The structural feature of faulted-sags is closely related to the basement structures. The complex syncline faulted-sags that superimposed on the complex synclines in almost NE/NNE striking are controlled by the complex synclines. The north sags that included wide but shallow grabens and/ or half-grabens exhibited ductile extensional deformation, major faults tended to slip in superficial zone. The sags connect in a parallel pattern. The south sags that included long narrow but shallow grabens and/or half-grabens exhibited transtensional deformation, major fauIts tended to slip in superficial zone. The sags connect in an echelons pattern. The faulted-sags that superimposed on the the Erlian-I-/egenshan m61ange zone in a/most NE/NEE striking are affected by the Erlian-Hegenshan m61ange zone. The Erlian-Hegenshan m61ange zone faulted-sags that included long narrow but deep grabens and/or half-grabens exhibited extensional deformation, major faults tend to extend deeply. The sags connect in a parallel pattern.