Vegetation and climate changes of Late Miocene-Early Pliocene have been deduced based on pollen research from Wenwanggou and Xiaoshigou sections near Leijiahe village (ca 35°04′15″N，107°43′30″E). The two sections are quite famous of rich micromammalian fossils. Before ca. 6.5 Ma， open forest-grassland was distributed in the studied area indicating a temperate and humid condition at that time. In the period between ca.6.5 and 5.8 Ma BP (Late Miocene) predominance of Chenopodiaceae and Artemisia implies that desert or desert-grassland was developed in the area and the climate should be cold and dry. During the time interval from ca.5.8 to 3.4 Ma BP mixed conifer and broad leaved deciduous forest with a few subtropical tree taxa had replaced the arid desert vegetation indicating a warm and humid climate. The climate aridity event of Late Miocene can be correlated with the global climatic event.
甘肃灵台雷家河地区中新世晚期—上新世早期孢粉植物群
吴玉书
（中国科学院植物研究所，北京100093）
摘要：通过甘肃灵台雷家河地区(约35°04′15″N,107°43′30″E) 富含小哺乳动物化石文王沟和小石沟剖面的化石孢粉研究,阐述了该区晚中新世—早上新世(6.5～3.4 Ma BP)的植被发展历史。约6.5 Ma前为疏林草原,气候温湿。约6.5～5.8 Ma BP, 为以藜(Chenopalaceae )和蒿(Artemisia)占绝对优势的荒漠或荒漠草原植被,反映气候冷干。5.8～3 .4 Ma BP,针阔叶林分布本区,以松(Pinus)和桦(Betula)为优势并有山核桃( Carya)、油杉(Keteleeria)、铁杉(Tsuga)等少量亚热带植物存在,此时期气候暖湿。本区中新世末期气候事件与全球冷干气候事件一致。
关键词： 孢粉植物群；古植被；古气候；中新世晚期=上新世早期；雷家河；甘肃灵台
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