松辽盆地新站地区嫩江组三段孢粉-藻类组合及其环境

On the Sporopollen-Alga Assemblages and Environments from the Third Member of Nenjiang Formation in the Xinzhan Area of Songliao Basin

依据松辽盆地西南部新站地区嫩江组三段孢粉和藻类化石百分含量纵向变化特征,自下而上划分7个能识别水体盐度变化的孢粉和藻类组合:Cyathidites-Pinuspollenites-Dinogymniopsis组合,指示缩小的微咸水湖相沉积环境;Dinogymniopsis-Leiosphaeridia-Pinuspollenites组合,代表水域扩大的微咸水湖相沉积环境;Cicatricosisporites-Pinuspollenites-Botryococcus组合,代表水域缩小的淡水-微咸水湖相沉积环境;Dinogymniopsis-Chlamydophorella-Taxodiaceaepollenites组合,反映淡水与微咸水频繁交互变化的浅湖相沉积环境;Cicatricosisporites-Pinuspollenites-Pediastrum组合,代表水域缩小的淡水湖相沉积环境;Nenjiangella-Balmula-Cyathidites组合,代表水域范围较大的淡水湖相沉积环境;Cyathidites-Tri-lobosporites-Botryococcus组合,指示水域缩小的微咸水湖相沉积环境。

The Third Member of Nenjiang Formation is located in the Xinzhan area, the southwestern part of Songliao basin. According to the changes of sporopollen-alga assemblages from bottom to top, seven sporopollen-alga assemblages were recongnized for the Third Member of Nenjiang Formation, which can indicate the salinity changes of water body of the take. They are （in ascendling order） ：Cyathidites-Pinuspollenites-Dinogymniopsis assemblage which indicates a brackish lake environment with a shrinking water body, Dinogymniopsis-Leiosphaeridia-Pinuspollenites assemblage which indicates a slightlysaltied lake environment with a enlarging water body,Cicatricosisporites-Pinuspollenites-Botryo- coccus assemblage which indicates a fresh-water to slightlysaltied lake environment with a shrinking water body,Dinogymniopsis-Chlamydophorella-Taxodiaceaepollenites assemblage which indicates a shallow lake environment transforming from fresh-water to brackish water frequently, Cicatricosisporites-Pinuspollenites-Pediastrum assemblage which indicates a fresh-water lake environment with a reducing water body,Nenjiangella-Balmula-Cyathidites assemblage which indicates a fresh-water lake environment with a broad water body,and Cyathidites-Trilobosporites-Botryococcus assemblage which indicates a brackish lake environment with a shrinking water body.