吉林万昌地区始新世—中新世孢粉组合及其地层意义

Eocene-Miocene palynological assemblages in Wanchang area of Jilin and their stratigraphic significance

吉林省万昌地区万参一井孢粉化石丰富,自下而上划分5个孢粉组合。Z1组合孢粉化石较少,均为古近系常见孢粉,偶见褶皱粉,时代为早始新世;Z2组合出现始新世特征分子杵纹粉,还有小刺鹰粉、高腾粉及褶皱粉等零星出现,时代为中晚始新世;Z3组合蕨类植物孢子含量为剖面最高值,草本被子植物花粉较Z1、Z2组合有所增加,时代为早渐新世;Z4组合仍含较多的蕨类植物,草本被子植物花粉与Z3组合相当,时代为晚渐新世;Z5组合草本被子植物花粉含量较高,达剖面最高值,尤其以蒿粉+藜粉+菊粉+禾本粉等为代表,时代为中新世。

Abundant sporo-pollen fossils are found in Well Wancan 1 of Wanchang area in Jilin,which can be divided into 5 palynomorph assemblages in ascending order.In the Z1 assemblage aged in early Eocene,the sporo-pollen fossils are less in amount,and common in Paleogene for occurrence,with Plicapollis seen occasionally.In the Z2 assemblage aged in middle-late Eocene,Pistillipollenites characteristic for Eocene,and assciated with Aquilapollenites spinulosus,Gothanipollis and Plicapollis occurred sporadically.In the Z3 assemblage aged in early Oligocene,the fern spores reach a peak in quantity for this profile,and the herbaceous angiosperm pollen more increased than those in Z1 and Z2 assemblages.In the Z4 assemblage aged in late Oligocene,more fern spores still occurred while herb aceous angiosperm pollen are similar to those of Z3 assemblage in content.The Z5 assemblage has a peak of herbaceous angiosperm pollen in contents for this profile,particularly shown by Artemisiaepollenites ＋ Chenopodipollis ＋ Compositoipollenites ＋ Graminidites,which indicates Miocene in age.