冀中拗陷断裂形成机理的探讨

晚中生代末或早新生代初以来,泰山隆起相对上升,在隆起两侧产生拉张应力,致使华北盆地北部和苏北盆地的基底在薄弱地带被拉开,形成一系列的一边断一边倾的箕状断陷。冀中拗陷的基底断裂是在统一拉张、翘倾运动中形成的。因此一边断一边倾的翘倾断块构成基底构造运动的基本构造单元。在基底翘倾断块之上同步沉积的下第三系碎屑岩的重力和区域拉张的叠加作用、以及翘倾构造应力条件下的重力滑动作用是形成冀中拗陷的表层断裂的动力;其次,重力滑动诱发下的塑性拱张、基岩隆起、沉积压实也是加剧形成表层断裂的动力。

An approach to genesis mechanism of fault system in Mid Hebei depression

Taishan rise began to uplift relatively in late Mesozoic or early Cenozoic, The tensile stress at both sides of Taishan rise fractured the weak parts of the basements of north Jiangsu basin and north hiorth China basin, creating a series of semigrabens,The basement fault system in Mid Hebei depression was created by the general tensile-tilting tectonic movement; therefore, the tilted fault block, whose one end is faulted and the another tilted, is a basic unit in basement tectonic movement, The gravity sliding stress which resulted from the areal tensile-tilting tectonic force and from the gravity of Paleogene elastic rocks synchronally formed on these basement tilted-fault blocks was the power to fracture nVerlying strata in Mid Hebei depression, In addition, other factors such as plasticarched e:ctension induced by gravity sliding, base rock rising, and consolidation settlement of sediments also brought tectonic forces which promoted overlying strata fractured.