摘要:
通过对长江三角洲前缘地区高桥G2孔、上海斜2孔等晚第四纪地层的孢粉研究,划分出了6个孢粉组合带,并结合临近钻孔的孢粉研究资料,恢复了本地区植被演替、气候波动的六个阶段:第一阶段为稀疏的针叶、落叶阔叶混交林,反映气候冷干(晚更新世晚期);第二阶段为针叶、阔叶混交林草地,反映气候温凉略湿(前北方期);第三阶段为含常绿阔叶树的针叶、阔叶混交林,反映气候温和略干(北方期);第四阶段以栲属、青冈栎为主的常绿阔叶林,反映气候暖热潮湿(大西洋期);第五阶段是以栎、松、蒿为主的针叶、阔叶混交林,反映气候温和略干(亚北方期);第六阶段是以落叶栎类、常绿栎类、松为主的落叶阔叶、常绿阔叶、针叶混交林草地.这六个阶段为本地区的地层年代划分和对比提供了可靠的证据,为晚第四纪古植被、古气候、古环境的重建提供了孢粉学资料.
Abstract:
Six palynolo gical assemblages were disting uished through an intensive study on pollen and spores from Cores G2 and XT2 at the frontedge of the Changjiang River Delta.Combined with the data from other cores nearby,six stages about the evolution of vegetation and climate were reconst ructed for the Late Quaternary on this area as follows:mixed sparse forest of conifers and deciduous broad-leave trees,reflecting a cold and dryclimate(Late Pleist ocene);mixed forest of conifers and broad-leave tree-sgrassland,reflecting a temperate and little moist climate(sub-arctic period);mixed forest of conifers and broad-leave trees with a fewevergreen broad-leave trees,reflecting a temperate and slightly dryclimate(the boreal period);evergreen broad-leave forest being mainly composed of Castanopsis and Quercus(evergreen),indicating a hot and moist climate(the Atlantic period);mixed forest of conifers and broad-leave trees,indicated by Quercus,Pinus and Artemisi a as main elementin palynological assem blages,reflecting a warm and little dryclimate(the sub-boreal period);mixed forest of deciduous broad-leaves,evergreen broad-leaves and conifers,Quercus(deciduous,evergreen) and pines,being the main components,reflecting a warm and wet climate(the sub-Atlantic period).These fluctuations coincide with the global climatic changes.The present study provides reliable evidence for biostratig raphy and reconstructions of paleo vegetaton,paleoclimate and paleoenvironment in this area from the Late Quaternary on.
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