25000年以来渤海湾西岸古环境探讨

APPROACH TO PALAEO-ENVIRONMENT IN THE WEST COAST OF BOHAI BAY SINCE 25000a.B.P.

本文依据孢粉、微体古生物、放射性碳测年、因子分析等资料,表明25000a,BP以来渤海湾西岸的古植被,古地理环境演变既受气候冷暖变化的影响,又受海平面变化的制约。25000—23000a,BP为高海平面时期,古植被为森林草甸植被,23000—12000a,BP,气候冷干,为低海平面时期,以草原植被为主,前期和后期为沼泽草甸植被。12000—5000a,BP气候温凉或温暖湿润为海平面上升时期,为阔叶林草甸或沼泽草甸植被,5000a,BP以来,气候变凉变干,为海退时期,古植被由沼泽草甸演变为盐生草甸。

Analyses of pollen, micro-palaeontology, radiocarbon dating and factor analysis showed that, the evolution of vegetation and geographical environment in the west coast of Bohai Gulf since 25000a. B. P. was influenced by both climatic changes and sea level fluctuation. During the period of 25000-23000 a, B. P. the sea level was high, the vegetation type was forest and grassland. During 23000—12000a. B. P., it was cold and dry, with low sea level and grassland vegetation type, but grass moor vegetation appeared at the beginning and the end of' this period. Period from 12000—5000a. B. P. was a perios of sea level' rising and a period of climatic change from cool to warm and humid, with the vegetation of broad-leaves forest and grass or grass swamp. After 5000a. B. P., it became cool and dry. It was a regression period of sea level, with a vegetation succession from grass swamp to salt meadow.