抚顺盆地中-晚始新世古植被与古气候

Paleovegetation and Paleoclimate during Mid-Late Eocene in Fushun Basin

为重建东北地区中-晚始新世古气候,对抚顺盆地孢粉进行传统鉴定,利用有序聚类分析划分孢粉组合,结合共存分析法对孢粉组合定量化以建立研究区的古气候参数值.鉴定出孢粉67属,划分出(I)Quercoidites-Tricolpopollenites-Betulaceoipollenites组合;(Ⅱ)Piceapollis-Tiliaepollenites-Chenopodipollis组合;(Ⅲ)QuercoiditesBetulaceoipollenites-Ulmipollenites组合;(Ⅳ) Pinuspollenites-Abietineaepollenites-Ephedripites组合;(Ⅴ)Betulaceoipollenites-Taxodiaceaepollenites-Quercoidites组合,其中组合Ⅰ、Ⅱ、Ⅲ时代为中始新世;组合Ⅳ、Ⅴ时代为晚始新世.植被类型也经历了:落叶阔叶林-草原型植被→针阔叶混交林-草原型植被→落叶阔叶林-草原型植被→针叶林→针阔叶混交林的转变.气候带经历了由亚热带、亚热带-温带湿润性气候向温带半湿润性气候的转变,年均温和年降雨量均呈降低的趋势,这些变化趋势与全球温度变化趋势相耦合.

For rebuilding the paleoclimate during Mid-Late Eocene in Northeast China, it analyzes the palynological characteristics in Fusun basin. Combining coniss analysis with co-existence approach, it quantitatively reconstructs the paleoclimate parameters in research area. 67 genera are identified and divided into 5 assemblages as:(I) Quercoidites- Tricolpopollenites- Betulaceoipollenites Assemblage;( Ⅱ) Piceapollis - Tiliaepollenites - Chenopodipollis Assemblage;( Ⅲ) Quercoidites-Betulaceoipollenites -Ulmipollenites Assemblage;( Ⅳ)Pinuspollenites-Abietineaepollenites-Ephedripites Assemblage;( Ⅴ) Betulaceoipollenites -Taxodiaceaepollenites-Quercoidites Assemblage. The age of assemblages Ⅰ, Ⅱ, Ⅲ belongs to Middle Eocene, and the age of assemblages Ⅳ, Ⅴ belongs to Late Eocene. The vegetation types of the basin experienced the transformation as deciduous broadleaf forest-steppe type vegetation→coniferous and broadleaf mixed forest-steppe type vegetation→deciduous broadleaf foreststeppe type vegetation→ coniferous forest→coniferous broadleaf mixed forest. The climatic zone changed from subtropical-temperate to temperate, the humidity changed from humid to semi-humid, and the average annual moderate and annual average rainfall decreased. This trend is coupled with the global temperature trend.