河南东濮地区晚始新世至渐新世轮藻植物群及其古环境探讨

东濮地区晚始新世沙河段组四段上部至三段轮藻植物群生存于含钙量高的咸化型水体中，它们的横向分布反映了湖盆中部存在着一个ＮＮＥ向的隆起地带。早渐新世沙河街组二段轮藻植物群生长于含钙量低的淡水水体中，它们的横向分布反映了湖盆中部古地形自南向北高低相间。晚渐新世东营组轮藻植物群生存于含钙量低的淡水水体中，它们的横向分布反映了湖盆的古地势较为平坦。

LATE EOCENE AND OLIGOCENE CHAROPHYTES FROM THE DONGPU AREA, HENAN AND THEIR PALAEOENVIRONMENTAL SIGNIFICANCE

The late Eocene charophyte Raskyella dongpuensis-Shandongochara decorosa Flora from the upper part of Member 4,and Member 3 of the Shahejie Formation in the Dongpu Area,Henan lived in a salinized water body with high calcium content;its horizontal distribution reflects the existence of a NNE-trend underwater swell at the center of the lake basin. The early Oligocene charophyte Charites producta-Dongmingochara concinna Flora from Member 2 of the Shahejie Formation lived in freshwater environment;its horizontal distribution shows W-shaped palaeotopographic features. The middle Oligocene charophyte Charites columinaria -Obtusuchara cf. nanoconia Flora from Member 1 of the Shahejie Formation lived in a salinized water body with high calcium content;its horizontal distribution shows an alternating high and low topography from north to south in the lake basin. The late Oligocene charophyte Charites molassica-Maedierisphaera ulmensis Flora from the Dongying Formation lived in freshwater environment with low calcium content;its horizontal distribution shows rather flat palaeotopographic features in the lake basin.