济阳坳陷桩海地区中生界同位素年代地层学研究

济阳坳陷中生界分布广泛,具有油气成藏的基本地质条件,并取得了一定的勘探发现,但其勘探程度和研究程度相对较低,包括地层划分、沉积体系、储层特征、控藏因素等。特别是地层时代、分层与分界等基本的地质问题尚存在不同的观点和认识。根据区内14口井的10个火山岩全岩样品和79个小于2μm的泥岩自生伊利石样品,开展K-Ar法同位素年代地层学测定,分别确定了中生界的坊子组、蒙阴组、三台组和西洼组的绝对年龄值,将坊子组划归下侏罗统,蒙阴组为中侏罗统,缺失上侏罗统,并明确了各组的接触关系。

A Study on Mesozoic Isotopic Chronostratigraphy in Zhuanghai Area,Jiyang Depression

Mesozoic strata are widely distributed in the Jiyang depression with basic conditions for oil and gas reservoiring. Some prospecting findings have been archived, but relatively low prospecting and research degrees, including the knowledge on stratigraphic division, sedimentary system, reservoir characteristics, and reservoir controlling factors. Especially different ideas and understandings existed on basic geological issues of strata ages, divisions and boundaries. Based on 10 volcanic rock bulk-rock samples and 79 mudstone 2μm authigenic illite samples from 14 boreholes in the area, carried out isotopic K-Ar method chronostratigraphic dating. Thus absolute ages of Mesozoic Fangzi, Mengyin, Santai and Xiwa formations have been determined respectively. That is settled the Fanzi Formation into Lower Jurassic Series, Mengyin Formation Middle Jurassic Series, while Upper Jurassic Series hiatus, then contact relations between them decided.