Nine Fossil Plants Of Fagaceae From The Pliocene In Baoshan, Yunnan And Paleoenvironmental Analysis

Yunnan has been affected by the Himalayan tectonic movement since the Neogene, which has formed many intermountain basins and tridimensional climate, provided a unique environment for the formation and deposition of plant fossils. The abundant well-preserved fossil plants from the intermountain basins are good materials for the studies of plant systematic evolution, various vegetation conditions, paleoenvironmental and paleoclimatic evolvement.The Baoshan Basin, a major Neogene coal-bearing basin in West Yunnan, lies in the Southeast edge of the Qinghai-Tibetan Plateau, containing numerous animal and plant fossils. Nine angiosperm fossil plants from the Pliocene Yangyi Formation in Baoshan, Yunnan Province were studied in this paper. The study of the fossil plants will help us to understand the uplift and paleoclimatic evolvement of the Qinghai-Tibetan Plateau.Based on leaf architecture and cuticular analysis, the nine angiosperm fossil plants from the Pliocene Yangyi Formation have been identified as:Quercus cf. presenescens, Quercus cf. serrata, Quercus sp., Quercus cf. patelliformis, Quercus sp.l, Quercus sp.2; Lithocarpus cf. fenestratus, Lithocarpus cf. dealbatus; Castanopsis cf. delavayi.The paleoclimatic parameters were quantitatively reconstructed based on the Coexistence Approach of the NLRs of 9 fossil species from Yangyi flora. The results show that the Pliocene paleoclimate of Baoshan Basin is characterized by the mean annual temperature (MAT) 10.5℃～12.7℃, mean annual precipitation (MAP) 642.3 mm～1749.2mm, and relative humidity (RH) 65%-79%, which implies that the climate in the Pliocene was warm and humid in Baoshan Basin, Yunnan.The palaeovegetation and palaeoclimate of Pliocene have been reconstructed from the combination of leaf fossils and pollen from the Yangyi Formation. The vegetation was lush and the forest was made up of many layers.