摘要
根据孢粉分析,本文提出河北东部滦河下游平原地区,第四纪更新世时期的植被,主要由温带针叶和阔叶落叶树木及大量耐旱耐寒的草本植物所组成。植被发展过程可以分出四个温暖阶段和四个寒冷阶段。共温暖期的平均气温可能比现代略低。寒冷期、草原植被曾有广泛分布,很可能处于冻土带或冰绿带的自然地理环境。
Based upon the pollen analysis of the east Hebei’ plain, the vegetational history and its characteristics in geographical development are discussed.The east Hebei plain is situated in the warm temperate deciduous forest zone and the northern side of the oceanic monsoons of midlatitude. The Quaternary sediments of this area is widely and deeply distributed.The samples for pollen studies were taken from drill cores. The fluvial and lacustrine sediments deposited continually and no change of lithological character occurs.The pollen assemblage is composed of temperate elements. In general, herbs especislly Artemisia represent an obviously great number, and in trees, Pinus is the dominant. The deciduous pollen only take a little component.According to pollen sequences the Pleistocene series can be divied into four warm and four cool intervals.In general the characteristic of the climate in Pleistocene was cool and dry. In warm intervals the mean temperature maybe lower than that of the present at the same region. In the cool intervals, however, tundra and steppe had a widedistributed area, which maybe situated in a frozen soil zone or in periglacial environments.Through the end of the Tertiary to the beginning of the Quaternary the climatic changes showing in the assemblages are obvious. The warm climate expressed by Carya, Liquidambar, Tsuga etc. changed to the cool climate expressed by Pinus, Artemisia and Chenopodiaceae assemblage, and the interval appearance of the latter coincided with the Olduval of the paleomagnetics event in 1.87-1.68 m.y.B P. The stratigraphic position marked as the Neogene/ Quaternary boundary is nearly seated in 400 meters deep of the drill core.
出处
《地理研究》
1985年第4期47-54,共8页
Geographical Research
