东北三江平原几个钻孔剖面的孢粉组合分析及其意义

三江平原位于我国东北的边陲,系黑龙江、松花江、乌苏里江汇流而成的冲积平原。其位置在东经129°11′20″至135°5′10″,北纬43°49′55′至48°27′40″(图1)。

THE SPORO-POLLEN ASSEMBLAGES IN THREE WELL LOGS FROM THREE-RIVER PLAIN, NORTHEAST CHINA AND THEIR GEOLOGICAL SIGNIFICANCE

A sporo-pollen analysis has been made for three well logs from Three-river Plain, where abundant pollen grains of shrubs and herbaseous plants, such as Pinus, Betula, Quercus, Ulmus, Tilia, Ephedra, Artemisia, Chenopodiaceae, Gramineae, etc. have been found. The well logs studied can be divided from bottom to top into four sporo-pollen zones and four flora sections: I. Pinus, Picea asperata, and Abies pollen diminated zone, corresponding to coniferous-broad leaf forest section; II. Betula pollen dominated zone and Betula forest vegetation section; III. Alnus,Ulmus and Quercus pollen dominated zone and broad leaf forest vegetation section; IV. Pinus and Betula pollen dominated zone and coniferous or coniferous-broad leaf forest vegetation section.In comparison with the Quaternary pollen data from other areas, it can be concluded that the climate in zone I was relatively cold and dry possibly corresponding to the Dali glacial stage; the climate during the sedimentary period of zone II was also corresponding to the Preboreal-Boreal stage; the climate in zone III was warm and wet, corresponding to the Atlantic-Subboreal stage; and zone IV was of cool and dry climate possibly corresponding to the Subatlantic stage. The geological ages of the sediments of the zone I, II, III, and IV can be assigned to Late Pleistocene, Early Holocene, Middle Holocene, and Late Holocene, respectively.