Sporopollen Assemblages From The Palaeogene In The Tanhai Area Of Haunghua Depression, And Their Palaeoclimate Analysis

The author was provided with materials from the Geological Institutes of Dagang Oilfield Company of CNPC in Tianjin. The materials were collected August 2002 and the author analyzed them at the Bohai Laboratory of Petroleum Research center of CNOOC.This paper presents an analysis of sporopollen from the Tanhai area of Huanghua depression. Give location the material was collected from 8 well sites and connects of 126 samples taken at different depths to reflect the local stratigraphy. Their pollen samples provide essential clues to the evolution of paleo-ecology in the area.The following conclusion was formulated:1. Sporopollen from the Tanhai area of Huanghua depression can be used to make data led stratigraphic discussion of the Shahejie group. From low strata to high, they can be designated as Shahejie I, Shahejie II , Shahejie III, Sahahejie IV followed by the mend as of the Dongying group as follow: Dongying I, Dongying II, Dongying III. The Kongdian member was not evident in this area.Establishing the stratigraphic sequence of the Tanhai area provides an important foundation for further petroleum research and exploration.2. We have determined and describe that fossil 66 species of 34 genera totally.3. According the characteristics of the sporopollen fossil in the Shahejie and Dongying Formations, two sporopollen assemblages and six sub-assemblages are recognized. Their geological ages have also been discussed as follows:Quercoidites assemblage1 )Ephedripites- Taxodiaceaepollenites- U. tricostatus-Pterisisporites sub-assemblage2)Q.microhenrici- Alnipollenites- U.minor sub-assemblage3)Ephedripites- Rutaceoipollis-Meliaceoidites sub-assemblage4)Quercoidites-Labitricolpites sub-assemblageUlmipollenites assemblage1)U. undulosus-Piceaepollenites-Tsugaepollenites sub-assemblage2)Polypodiaceaesporites-Juglandaceae-Tiliaepollenites sub-assemblage4. We have districted Shahejie III and Sahahejie IV belong to Eocene, Shahejie II and Shahejie I is Early and Middle Oligocene, and the Dongying group belong to Late Oligocene.5. Sporopollen from the sedimentary sequence that makes up the Tanhai area indicates a change from grasslands into a hood leaf forest environment as indicated ley leaf litter from coniferous trees. Then the Palaeoclimate evolutes from arid to a moist warmer sub-typical environment.