贝尔凹陷构造层建造与改造特征分析

ANALYSES ON THE FORMING AND REFORMING CHARACTERISTICS FOR THE TECTONICALLY CONTROLLED FORMATIONS IN BEIER SAG

为了理清贝尔凹陷断陷期的变形过程,应用地震剖面解释、平衡剖面及剥蚀量恢复等技术,对贝尔凹陷断陷期的拉伸建造、挤压改造模式进行了刻画。研究认为:贝尔凹陷断陷期经历了交替进行的3期建造和3期改造作用,建造期发育的复式断陷经过了同期和不同期的断陷叠加,同期断陷分为并联式半地堑、并联式地堑复合形式,不同期断陷分为继承型半地堑、继承型地堑叠加形式;断陷期广泛发育的扇三角洲、辫状河三角洲、湖底扇等沿控陷断裂或斜坡走向呈珠串状展布;铜钵庙组、南一段及南二段沉积末期凹陷经历了强烈的张扭变形,从而奠定了现今的构造格局。

Abstract： In order to clarify the deformation process during the rifting period of Beier Sag, by means of the expla- nation of the seismic profiles, balanced cross section and denudation buildup techniques, the characterizations of the tension formation and compressional reformation are conducted in the above period. The researches show that in the rifting period the sag alternately experienced 3 times of the formation action as well as 3 times of reformation action. The complex depression developed in the forming period has undergone the rift superposition in the same and different periods. In detail, the former can be further divided into the parallel half-graben and complex form of the parallel half-graben; the latter can be further classified into the inherited half-graben and inherited graben superpositions; the fan delta, braided river delta and sublacustrine fan and so on extensively developed in the rift period distribute along the rift-controlled faults and slope strikes in the beaded form; the sags in the late sedimentary periods of Tongbomiao Formation, Member 1 and 2 of Nantun Formation experienced strong tension-twist deformation, thus the present tectonic framework has laid.