中国第四纪孢粉植物群的分布

DISTRIBUTION OF QUATERNARY PALYNOFLORA IN CHINA

本文依据已发表的70多个地点的孢粉资料,讨论第四纪各主要时期孢粉植物群的分布,揭示了全球气候变化及青藏高原隆升对我国第四纪环境的影响。发现第四纪期间存在三次草原扩张时期,它与自然环境恶劣的时间相接近,时间大约为2.5—2.6,1.1—0.8Ma B.P.及25—13Ka B.P.。第四纪孢粉植物群的分布可划分为三个大区8个区,三大区为北方大区,南方大区及青藏大区。

This paper discusses distribution and evolution of Quaternary palynoflora of China according to palynological data from 70 localities. Various Quaternary palynofloras have been found in China. They could be grouped into 2 categories and 8 types. Quaternary palynoflora features were sharply different in various areas. According to the differences of palynoflora components and the types, the geograpgical distribution of the Quaternary palynoflora could be divided into three provinces and eight regions: I the northern China province (I1 Northeast China Region, I2 North China Region, I3 Northwest China Region); Ⅱ the southern China province (Ⅱ1 Central China Region, Ⅱ2 South China Region, Ⅱ3 Southwest China Region); Ⅲ the Qinghai-Tibet province (Ⅲ1 the northern Tibet Region, Ⅲ2 the southern Tibet Region).The distribution of Quaternary palynofloras still showed latitudinal zona-tion in the Early Pleistocene. The palynoflora differentiation between eastern and western China has been intensified gradually since the Middle Pleistocene. In the Late Pleistocene, two centers of floral distribution appeared in China. One was the high-cold flora in the Qinghai-Tibet Plateau, which successively changed into evergreen broadleaf forest southeastwards. The other was the high-latitude tundra flora in Northeast China, which gradually turned into evergreen broadleaf forest southwards. The difference between the two series was that the dry-hot shrub flora was limited to the river-vellay areas in Southwest China, while the shrub steppe and the open forest steppe widespread and occupied about ten latitudes in eastern China. Climatic cold-warm fluctuation made the Quaternary flora reappearing as-time passed, the horizontal biomes migrating southwards and northwards repeatedly and the vertical vegetation zones moving up and down. The migrating scopes of the biomes could span 12-17 latitudes in the eastern flatlands, and the moving ranges of the zones could be 1-2km in the western mountains of China. The Quaternary palynoflora of China was characterized by abundant cate. gories, complete evolutionary process and varied geographical distribution.