吉林省伊通地区白土山组地层的重新厘定  

A REVIEW ON THE BAITUSHAN FORMATION IN YITONG REGION, JILIN PROVINCE

作　　者：程新民[1] 

机构地区：[1]长春地质学院

出　　处：《吉林地质》1990年第1期69-73,共5页Jilin Geology

摘　　要：伊通火山群周围分布的砂砾石层定为第四系早更新世白土山组,通过对大孤山、西尖山采用K—Ar稀释法测定,分别为8.70Ma、20.80Ma;该地层孢粉组合以栎、榆、桦属花粉占优势,松柏类花粉含量较高,为阔叶混交林带植被环境。故应将该套地层重新厘定为上第三系中新统水曲柳组。Layers of loose sand and gravel are distributed around the Yitong Volcanic cluster. The former geologists called then the Baitushan formation, early Pleistocene, Quaternary. With a thorough investigation on the Yitong volcanic cluster, more and more measured data on isotope, of basalt are obtained. Through the determination by K-Ar dilution method from Dagushan and xijianshan, 8.70Ma and 20.80 Ma in age are obtained respectiveey, indicating that the basalt intruded in the Baitushan formation should belong to Miocene of Neogene in age. Through investigation and sporo-pollen sumpled from the section, it is indicated that the sporo-pollen is very plentiful and its assemblage is composed chietly of oak, elm and birch witha a higher content of Coniferales. In addition, there are some subtropical pollens indicating that the vegetation form belongs to broad-leavedmingled forest. According to stratigraphic comparison, isotopic dating and characteristics of sporopollen assemblage, the Baitushan formation, early pleistocene, Quaternary in Yitong region should belong to the shuiquliu formation, Miocene, Neogene.

关 键 词：白土山组 火山群 K-Ar稀释法 

分 类 号：P535.2[天文地球—古生物学与地层学]