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通过对山东青东凹陷西部古近纪地层孢粉研究,共建立4个孢粉组合:Ⅰ.Ephedripites-Inaperturopollenites-Ulmipollenites minor,Ⅱ.Pinaceae-Ulmoideipites tricostatus-Taxodiaceaepollenites,Ⅲ.QuercoiditeshenriciTaxodiaceaepollenites hiatus,Ⅳ.Alnipollenites-Juglanspollenites-Polypodiaceaes porites。根据与渤海湾地区的孢粉资料对比,确定4个组合的时代分别为早始新世晚期—中始新世早期、中始新世早—中期、中始新世中—晚期、中始新世晚期—晚始新世。该区古近纪植被类型由落叶、阔叶和灌木混交林逐步转变为落叶、常绿阔叶和针叶混交林,古气候经历了干热的亚热带气候到湿热的亚热带气候再到亚热带型温暖气候的变化。沙四段上部到沙三段下部沉积时期是研究区烃源岩最为发育时期。
Four sporo-pollen assemblages were established in the Paleogene strata in western Qinghai depression of Shandong Province: Ⅰ. Ephedripites-Inaperturopollenites-Ulmipollenites minor, Ⅱ.Pinaceae-Ulmoideipites tricostatus-Taxodiaceaepollenites, Ⅲ.Quercoiditeshenrici Taxodiaceaepollenites hiatus, Ⅳ.Alnipollenites- Juglanspollenites-Polypodiaceaes porites. According to the data of sporopollen in the Bohai Bay region, the ages of the four assemblages are respectively Early Early Pliocene-Middle Eocene, Middle-Early Eocene-mid-Middle Eocene, Middle-Eocene Middle- Late Epoch - Late Eocene. The Paleogene vegetation types in this area are gradually changing from deciduous, broad-leaved and shrub-mixed forests to deciduous, evergreen broad-leaved and mixed coniferous forests. The paleoclimate experienced a dry-hot subtropical climate to damp-heat subtropical climate and subtropical warming Climate change. The depositional period from the upper part of Sha 4 to the lower part of Sha 3 is the most developed period of source rock in the study area.