THE MIOCENE SPOROPOLLEN ASSEMBLAGES OF THE EASTERN ZHOUKOU DEPRESSION AND THEIR GEOLOGICAL SIGNIFICANCE

It is the first time to report that the sporopollen assemblages of the Guantao Formation have been discovered in the log section of the Eastern Zhoukou Depression. The assemblages can be divided into two groups. The lower group is in age of early Miocene depending on the correlation to the adjacent areas while the characteristics of the upper group are similar to those of the Shanwang Formation in Shandong provinc and the Taidao type (mid-Miocene) in Japan, and more similar to those of the late Neigene sporopollen assemblage (in age of mid-late Miocene) in the North Jiangsu-South Yellow Sea areas. It is proposed that the assemblage in age of early stage belongs to north subtropical type while that in age of mid-late stages are transformed from warm to cool zones based on the characteristics of their vertical distributions.