广西合浦盆地古新世上洋组孢粉组合及其地层意义

广西合浦盆地上洋组在亚1井中有很好的揭示,明显表现为三分特征。作者通过对该井上洋组微体植物化石的研究,建立了三个孢粉、藻类组合,由下而上分别为:Boehlensipollis-Tricolporo-pollenites-Tricolpites-Ulmoideipites组合;Boehlensipollis qingjiangensis-Ulmoideipites-Nuxpollen-ites-Pentapollenites组合和Pinaceae-Ulmaceae-Liqudambarpollenites-Conicoidium组合。前两个组合可与北部湾长流组及广东南雄盆地上湖组等地古新世孢粉组合进行对比。第三个组合以松科花粉含量突然增加为特征,在我国许多地区晚古新世孢粉组合中都有反映。 上洋组植被在古新世早、中期以阔叶植物为特征,指示一种热带—亚热带型气候,早期干旱,中期略有缓和,晚期植被以针叶阔叶混交林为特征,表明气候变温凉。

PALEOCENE PALYNOLOGY OF THE SHANGYANG FORMATION,HEPU BASIN,GUANGXI,CHINA

The Shangyang Formation of the Hepu Basin shows a prominent character of tripartitionin descending order:red bed;dark grey mudstone; and red bed. In this formation,according tothe occurrence of microfloras from core section Yl,three microfloral assemblages are recog-nized in ascending order, namely, the Boehlensipollis-Tricolporopollenites-Tricolpites-Ulmoideipites Assemblage from Member 1; the Boehlensipollis qingjiangensis-Ulmoideipites-Nuxpollenites-Pentapollenites Assemblage from Member 2; and the Pinaceae-Ulmaceae-Liq-uidambarpollenites-Conicoidium Assemblage from Member 3. These assemblages can be cor-relatd with those of other areas. This formation may be dated as Paleocene. The Early and Middle Paleocene vegetation of this formation is characterized by thebroad-leaved forest,indicating a tropic-subtropic climate condition. The vegetation of Mem- ber 3 is characterized by the evergreen and deciduous coniferous broadleaved forest of theLate Paleocene,representing a trend towards a cooling climate.