冀北滦平盆地早白垩世陆相义县阶的重新厘定及其层型剖面  

Redefinition of the Lower Cretaceous terrestrial Yixianian Stage and its stratotype candidate in the Luanping basin,northern Hebei,China

作　　者：田树刚[1] 牛绍武[2] 庞其清[3] 

机构地区：[1]中国地质科学院地质研究所,北京100037 [2]中国地质调查局天津地质矿产研究所,天津300170 [3]石家庄经济学院,河北石家庄050031

出　　处：《地质通报》2008年第6期739-752,共14页Geological Bulletin of China

基　　金：国家自然科学基金项目《侏罗系-白垩系界线过渡期大北沟阶至义县阶连续剖面及化石分带研究》(编号:40472019);全国地层委员会项目《中国主要断代地层建阶研究》(编号:200113900076)联合资助

摘　　要：实测了冀北滦平西瓜园组李营-王家沟剖面和马圈村剖面,在开展多学科系统研究的基础上,把剖面划分为4个岩性段,建立了系统的叶肢介生物地层分带序列,进行辽西义县组与冀北西瓜园组的等时性对比,分析剖面的沉积相叠置特征,证明了剖面的沉积连续性和沉积旋回性变化,识别出剖面的4个三级层序,确定了义县阶的定义及其单位和界线层型。从而建议重新厘定"义县阶"的定义和层型,将冀北滦平李营-王家沟剖面作为下白垩统义县阶的单位层型,将冀北滦平马圈村大店子组—西瓜园组界线剖面作为义县阶的底界层型,将冀北滦平西瓜园组的时限范围定为义县阶;取消以张家沟大店子组时限范围所定的义县下亚阶,改为张家沟阶。The Liying-Wangjiagou section and Majuan section of the Xiguayuan Formation in Luanping County have been studied, and based on a multidisciplinary systematic study, the authors divided the section into four lithologic members, erected the conchostra- can biostratigraphic succession （five zones）, performed an isochronous correlation between the Yixian Formation of western Liaoning and the Xiguayuan Formation of northern Hebei, analyzed the features of superimposition of sedimentary facies and proved the continuity and cyclic variation of sedimentation. Four third-order sequences have been recognized in the section. Therefore it is proposed that the ＂Yixianian Stage＂ and its stratotype be redefined： the Liying-Wangjiagou section be taken as the unit stratotype candidate of the Lower Cretaceous Yixianian Stage, the boundary section of the Dadianzi and Xiguayuan formations as the lower boundary stratotype of Yixianian Stage and the time range of the Xiguayuan Formation of Luanping as the Yixiarfian Stage. The original lower substage of Yixian defined by the time range of the Dadianzi Formation of Zhangjiagou should be abolished and changed to the Zhangjiagou＇an Stage.

关 键 词：陆相义县阶 候选层型 冀北滦平盆地 

分 类 号：P534.53[天文地球—古生物学与地层学]