华北东部侏罗—白垩纪原型盆地及其演化

PROTOTYPE BASIN AND THE EVOLUTION IN JURASSIC AND CRETACEOUS IN EASTERN NORTH CHINA

在残留盆地展布、地层发育特征以及控盆因素分析的基础上,恢复了华北东部侏罗—白垩纪的原型盆地格局。研究表明,早—中侏罗世,华北东部处于古亚洲构造域向滨太平洋构造域演化的过渡阶段,为弱挤压成盆期,发育中小型山间盆地,早期盆地走向以近EW向为主,晚期NNE向盆地更为发育;盆地早期的沉积表现为对印支期造成的低洼地区的充填,晚期则表现为披覆式沉积。晚侏罗—早白垩世,华北东部构造演化主要受滨太平洋构造域的控制,进入大规模裂陷或断陷盆地发育阶段,火山活动强烈,原型盆地的展布具有明显分区性,受NW/NWW向、NE/NNE向断裂系统的控制,拉张断陷、拆离断陷、反转断陷及走滑拉张型盆地在不同的地区分布。晚白垩世,华北东部隆起剥蚀,仅少数地区沉积充填。

Based on the research of distribution,lithologic feature of strata and regional tectonic evolution of remnant basins,prototype basin in Jurassic and Cretaceous in the Eastern North China are reconstructed.The researches show that in Early and Middle Jurassic,the Eastern North China was in the transitional period from Paleo-Asian system to Paleo-Pacific system,there were a series of small intermontane basins in the Bobai Bay area,sediments filled the depression formed by Indosinian thrust faults and gentle fold at the early stage and widely distributed at the late stage.From Late Jurassic to Early Cretaceous,tectonic and basin evolution were influenced by the Izanagi plate's subduction to Asian continent.This Geotectonic transition led to the formation of large-scale rifts or faulted basins.Basin distribution and sediment filling were controlled by NW/NWW-trending and NE/NNE-trending fault systems.In Late Cretaceous,the areas to the west of the Tancheng-Lujiang fault zone were uplifted and denuded,with deposition of red fluvial-lacustrine sediments in a few basins.The remnant basins were the reflection of original sedimentation and late denudation.