摘要
全新世青藏高原的花粉记录，反映高原东南部和西北部截然不同的孢粉类型。东南部主要为常绿硬叶种类（Ｌｉｔｈｏｃａｒｐｕｓ／Ｃａｓｔａｎｏｐｓｉｓ，Ｃｙｃｌｏｂａｌａｎｏｐｓｉｓ，Ｅｉｒａｃｅａｅ，Ａｒａｌｉａ，Ｉｌｅｘ和Ｖｉｂａｒｕｎｕｍ）及潮湿亚热带成分（Ｐｌａｔｙｃａｒｙａ，Ｍａｌｌｏｔｕｓ，Ｐｏｄｏｃａｒｐｕｓ，Ｃｕｎｎｉｎｇｈａｍｉａ和Ｔｓｕｇａ等）。而西北部几乎没有乔木树种花粉，主要为干旱灌丛和草原成分（Ｃｈｅｎｏｐｏｄｉａｃｅａｅ，Ａｒｔｅｍｉｓｉａ，Ａｒｔｅｍｉｓｉａ，Ｅｐｈｅｄｒａ，Ｎｉｔｒａｒｉａ，Ｃｙｐｅｒａｃｅａｅ等）。文中根据青藏高原２０个湖沼孢粉资料，探讨了青藏高原全新世不同时段。不同地区的植被史及古气候状况。由于高原的特殊大气环流形势，夏半年受西南季风控制，由东南向西北，水份逐渐减弱；冬半年高原面受干冷西风环流影响，致使气候寒冷干燥。全新世植被总的面貌由东南向西北发生山地森林—寒冷灌丛与草甸—高寒草原—高山荒漠的地带性递变。１万多年来青藏高原，尤其东南部，西南季风变化规律大体上是１１０００—７１０００ａＢ．Ｐ．是季风逐渐增强至鼎盛，７０００ａＢ．Ｐ．以后至今是季风逐渐减弱，这与全球气?
Completely different characteristics of pollen spectra are shown by the pollen records from the Southeast and the northwest of the Qinghai-Xizang Plateau.In the southeast,the main components of pollen are evergreen sclerophyllous elements such as Lithocarpus/Castanopsis,Cyclobalanopsis,Eriaceae,Aralia.Ilex and Vibarunum,and moist subtropical elements such as Platycarya,Mallotus,Podocarpus,Cunninghamia and Tsuga.However,the main elements of dry shrub and steppe are the dominant components of pollen spectra in the northwest,such as Chenopodiaceae,Artemisia ,Ephedra,Nitraria and Cyperaceae,Because of special atmospheric circulation situation in summer.the Plateau is controlled by Southwest Monsoon with the occurrence of a decrease from southeast to northwest in the annual rainfall;but in winter,it is influenced by the west wind drift,when the climate is cold and dry.The Holocene vegetation on the Plateau changes from southeast to northwest,i.e.,from montane forest to subalpine shrub and meadow to alpine meadow and steppe and then to high-cold desert,reflecting the changes of the annual rainfall controlled hy the Southwest Monsoon.The Southwest Monsoon became stronger from 11000 to 7000aB.P.,reached its acme by ca.7000aB.P.and weakened gradually from 7000aB.P.to the present.The timing of vegetational and climatic changes based on pollen records generally support the results of global climatic-model experiments that predict a strengthened monsoon system during the early to middle Holocene followed by a weakened monsoon system.
出处
《微体古生物学报》
CSCD
北大核心
1996年第4期407-422,共16页
Acta Micropalaeontologica Sinica
基金
国家八五攀登计划青藏项目
