云南元谋盆地湾堡甘棠组植物群的叶化石和孢粉化石合计107种类型，分属86属，47科。植物叶化石包括18科，24属，35种。除一种裸子植物外，其它均为被子植物。被子植物中，榆科、桦木科、豆科无论属种或者化石数量都是最多；杨柳科、槭科、蔷薇科次之；壳斗科、樟科、杨梅科、鼠李科、忍冬科、胡颓子科、杜鹃科、香蒲料、禾本科均有代表。甘棠组的孢粉植物群也相当丰富，合计97个类型，分属72属，44科。以松科、榆科、禾本科及蕨类植物的水龙骨科最为丰富，胡桃科、壳斗科、金缕梅科及蕨类植物的凤尾蕨属也很常见。被子植物花粉占孢粉总数的50%--60%，以禾本科和榆属花粉含量最高，多在10%以上。裸子植物绝大部分为松科花粉，占孢粉总数的20%-30%。孢子以水龙骨科和凤尾蕨属为主，二者各占孢粉总数的5%-10%。发现于元谋盆地湾堡甘棠组的植物叶化石以及孢子花粉组合在成分上都是混合的类群。组合中既有相当多的湿润亚热带常绿阔叶林成分，也有耐干旱的胡颓子、杨梅、旱蕨等灌木、小乔木或草本分子，同时还有含量很高的、在半干旱环境下也能生存的禾本科、榆科花粉。据此推测甘棠组的植物群和孢粉组合反映了上新世时元谋地区的植被已经分化，盆地的周围山地生长有松科、壳斗科、樟科、胡桃科、金缕梅科为主的常绿和落叶阔叶树木或林块，可能有少许杜鹃科小乔木混杂其中，属于地带性植被。而在盆地内则是以禾本科、蔷薇科等为主，杂以大戟科、豆科、忍冬科、杨梅科等灌木或草本植物以及榆科、桦木科等树木组成的稀树灌丛草原型植被。盆地内的植被所反映的气候和周边地区相比，显得明显干旱。因此推测元谋盆地在2-3百万年前的中晚上新世已经发育成为金沙江流域的干热河谷盆地之一。

In the present paper a preliminary result is reported of the study on leaf and pollen flora from the Pliocene Gantang Formation near the Wanpu Village of Yuanmou Basin, Yunnan Province, SW China. The leaf flora contains 35 species and 24 genera of 15 families. All leaf fossils are identified to angiosperm except one genus of Taxodiaceae(? Taiwania ). Ulmaceae, Betulaceae and Leguminosae are the predominant families of the leaf flora both in species diversity and specimen quantity. Other important families are Salicaceae, Aceraceae, Rosaceae. Present in small number are the families of Fagaceae, Lauraceae, Myricaceae, Rhamnaceae, Caprifoliaceae, Elaeagnaceae, Ericaceae, Typhaceae, Graminosae. Pollen and spores are rich in the Wanpu flora with 97 types of 72 genera belonging to 44 families. The most aboundant families are Ulmaceae, Gramineae, Pinaceae(generally 20% 30% of total spores and pollen for each family) and the monolete spores of Pylopdiaceae(5% 10%). Angiosperm pollen, most of them are of Ulmaceae and Graminosae(over 10% respectively), occupies 50% 60% of the total. Juglandaceae, Fagaceae, Hamamelidaceae and Pteridaceae are common families, amounting to 1% 10% individually. Some pollen types probably related to xerophyte shrubs, e.g. Elaeagnus , Chenopodiaceae, have also been found in different quantities. The pollen flora also contains a number of subtropical evergreen forest elements of southern China, e.g. Lithocarpus/Castanopsis, Cyclobalanopsis, Symplocos, Reveesia, Alangium, etc. Either leaf flora or pollen assemblage is a mixed group of elements from subtropical evergreen forest and semi humid parkland. The mixture characters of leaf and pollen floras suggest pliocene vegetation differentiation in the Yuanmou area. On the surrounding high lands of the basin developed a subtropical broad leaved evergreen forest containing Fagaceae, Lauraceae, Juglandaceae, Sterculiaceae, Hammaelidacaae and Ericaceae, etc. Probably Pinaceae woodland also developed locally. While in the basin, grass land with some shrubs and/or herbs of Leguminosae, Elaeagnaceae, Myricaceae, Rosaceae, Euphorbiaceae, Caprifoliaceae developed. Ulmaceae, Betulaceae and other trees may grow in some areas of the basin with suitable environment. The climate in the basin was of semi humid subtropical type(with seasonal drought), which is similar to that of today. Our plant fossil data indicate that dry and hot basins along the Jinsha River in the northerm Yunnan area probably have been already existed in the mid Pliocene. This conclusion is interesting in tracing the history of monsoon climate in China.

Q914.6 Q914.72

国家自然科学基金 (No .497710 79)资助课题