河北宽城北杖子地区下马岭组沉积相特征

Characteristics of sedimentary facies of Xiamaling formation at Beizhangzi area,Kuancheng,Hebei

河北宽城北杖子地区新元古界青白口系下马岭组为一套碎屑岩沉积,主体岩性为深色页岩,氧化物的含量及组合的变化,在一定程度上指示了沉积环境的变化。通过对氧化物的含量变化情况进行分析,发现其值随沉积相区带的变化呈明显的变化规律;通过对该地区下马岭组野外实测资料,室内地球化学化验分析资料进行研究分析,认为该地区下马岭组沉积相为无障壁型海岸相和浅海陆棚相,可进一步划分为滨岸亚相和滨外陆棚两个亚相及前滨带、近滨带和陆棚泥三个微相类型,并总结了下马岭组的沉积相模式。

Xiamaling formation,Qingbaikou system in Upper Proterozoic at Beizhangzi area,Kuancheng,Hebei is a suit of clastic rock deposition with the main lithology as dark shale.The content and the assemblage of the oxide indicate the alternation of deposition environment.By analyzing the content alternation of the oxide,it is found that the values indicate a regular change of the sedimentary facies.Based on the study on field data of Xiamaling formation and the laboratory geochemical data,and on combinition with the research by predecessors,it is suggested that the sedimentary facies of Xiamaling formation at Beizhangzi area are composed of the barrier beach facies and the continental shelf facies, which can be further classified into two subfacies as the onshore facies and the offshore shelf facies,and three microfacies as foreshore zone facies,onshore zone facies and shale facies.And the sedimentary facies models of Xiamaling formation are summarized.