中国科学院南京地质古生物研究所机构知识库

Geochronology of Mesozoic volcanic rocks in Shandong province has direct connections with many major geological events in eastern China. In this study, volcanic rocks used for K-Ar dating are systematically sampled from four formations of Qingshan Group in the standard section of Jiaolai basin, and from Tianjialou Formation of Dasheng Group in Anqiu, as well as from Zibo, Mengyin and Juxian area. K-Ar dating of volcanic rock samples from Qingshan group shows that the age of this group ranges from 118Ma to 93Ma, corresponding middle to upper Cretaceous, and the ages of the four formations in this group are as follows: Houkuang Formation started from about 117Ma, belonging to Aputian; Bamudi Formation 109 similar to 103Ma, belonging to Albian; Shiqianzhuang Formation 103.7 similar to 93.3Ma, seated at upper Albian to Cenomanian, its bottom is about the top of Bamudi Formation, probably no discontinuity between the two formations; and Fanggezhuang Formation started from 93.3Ma, belonging to upper Cretaceous Turonian. Although difference has been existed, the age of Bamudi Formation vocanic rock in eastern Shandong Province is about the same of that in western Shandong Province. The age of lower Tianjialou Formation in Dasheng Group is similar to 95Ma, corresponding to upper Shiqianzhuang Formation of Qinshan Group, indicating that the two groups are crossed-correpondence. Volcanic rocks of Fangzi Formation of Zibo Group have early Cretaceous ages (107.7Ma and 120.1Ma), indicating that Jurassic volcanic rocks may be absent in Shandong.