长江口地区近7000a来的植被、气候演变研究

Studies on Evolution of Vegetation and Climate since 7000 Years ago in Estuary of Changjiang River Region

长江三角洲地区的孢粉资料已相当丰富,但崇明岛地区以前孢粉研究资料较少,本文对崇明岛北侧的 CY孔作了高分辨率的孢粉研究,详细地划出了大西洋期以来的 个孢粉组合带,并结合邻区钻孔孢 9粉资料研究,恢复了该区植被、气候演化的 个阶段。从大西洋中期起植被依次为:中亚热带含落叶树的 7常绿阔叶林;中亚热带北缘常绿阔叶、落叶阔叶混交林;北亚热带北缘以松、栎为主的落叶阔叶、针叶混交林;中亚热带北缘常绿阔叶、落叶阔叶混交林;北亚热带常绿阔叶、落叶阔叶、针叶混交林;北亚热带北缘含常绿阔叶树的落叶阔叶、针叶混交林;北亚热带常绿阔叶、落叶阔叶、针叶混交林。气候经历如下的波动:热暖潮湿—暖热湿润—温和略干—温暖湿润—温暖略湿—温而略干—温暖湿润,其气候波动与世界性的气候变化相一致,而且与海平面变化相吻合,从而为本地区古植被、古气候、古环境的重建提供了丰富的孢粉学资料。

According to the high-resolution sporopollen research about Core CY exiting in the north of Chongming Island, nine sporopollen assemblages have been distinguished since the Atlantic period. Combined with the sporopollen research about the core of adjacent areas, seven stages about the evolution of the vegetation and climate in this area are reconstructed. Since the mid -Atlantic period, the vegetation stages are: (1) evergreen broad-leaves forest including deciduous trees in the middle sub-tropic; (2) mixed forest of evergreen broad-leaves forest and deciduous broad-leaves forest on the north edge of the middle sub-tropic; (3) mixed forest of deciduous broad- leaves trees and conifer trees mainly including Pinus and Quercus on the north edge of north sub- tropic; (4) mixed forest of evergreen broad-leaves and deciduous broad-leaves forest in the north of middle sub-tropic; (5) mixed forest of evergreen broad-leaves, deciduous broad-leaves and conifer forest in the north sub-tropic; (6) mixed forest of deciduous broadleaves and conifer forest including evergreen broad-leaves trees on the north edge of north sub-tropic; (7) mixed forest of evergreen broadleaves, deciduous broad-leaves and conifer forest in the north sub-tropic. The fluctuation of the climate is as below: hot-warm and moist → warm and moist → temperate and a little dry→warm and moist→warm and a little moist→temperate and a little dry → warm and moist. Such fluctuation of the climate accords with not only the changes of the world climate, but also the changes of the sea level, providing reliable information for reconstruction of plaeovegetation, plaeoclimate and plaeoenvironment.