苏北盆地晚白垩世泰州期原型盆地恢复

通过研究区域地震剖面、砂砾岩分布特征等,确定苏北盆地晚白垩世原始盆地沉积边界;研究重矿物分布特征、砂岩体展布特征及联井剖面等,确定当时的沉积物源方向;通过区域地震相与单井相的结合,来恢复全区沉积相,进而恢复当时的原型盆地.研究认为,泰一段沉积时期,以建湖隆起为界,苏北盆地分为东台坳陷和盐阜坳陷2个大盆,在这2个坳陷内的凸起控制着地层的沉积厚度,沉积物源主要来自通扬隆起、鲁苏隆起和建湖隆起;而泰二段沉积时期,整个苏北盆地可能为一个大盆,东部以湖泊相沉积为主,西部为河流相与泛滥平原相,沉积物源来自通扬隆起和建湖隆起,但规模较小.

RESTORATION OF PROTOTYPE BASINS OF LATE CRETACEOUS TAIZHOU PERIOD IN THE NORTHERN JIANGSU BASIN

Based on studies of regional seismic profiles and conglomerate distribution characteristics,original deposition boundaries of the Northern Jiangsu Basin during late Cretaceous are confirmed.Researches of heavy minerals distribution,sandstone thickness changes and connected profiles of wells have found out sedimentary sources.Combining seismic facies and single-well facies,sedimentary facies of the region are restored;hence the prototype basin is also restored.When the 1st member of Taizhou Formation of Upper Cretaceous is deposited,the Northern Jiangsu Basin is divided in to the Dongtai Depression and the Funing Depression by the Jianhu Uplift.Uplifts in the 2 depressions control sedimentary thickness.Sedimentary materials come from the Tongyang,Lusu and Jianhu Uplifts.When the 2nd member of Taizhou Formation is deposited,the Northern Jiangsu Basin is an integrated basin.The east of the basin is dominated by lake facies and the west by fluvial and flood plain facies.Sedimentary materials come from the Tongyang and Jianhu Uplifts,yet the amount is relatively smaller.