摘要
最近一万年来,我国东部自然环境演变十分明显,主要表现为:10500—9000a.B.P.气温、海面快速回升、沟谷加快填平、冰川萎缩、冻土北移或上移、森林扩展、阔叶树增多;9000—6000a.B.P.高温高海面及6000—4000a.B.P.最宜环境中,出现新高温期与新冰期交替,亚热带常绿阔叶林扩展与减缩。北方针叶林北撤与南侵、喜暖的微体古生物—有孔虫化石富集与缺失,降水丰歉、泥炭发育与停止等一系列变化;4000a.B.P.以来,这是气温与海面趋向下降的环境,气候变温干,常绿阔叶树减少,海面降低引起河口外移,沟谷重新受切割,地面冲刷,堆积次生黄土,气候波动频率加快,变幅减弱,环境变差。
The environmental changes in eastern China have been distinct for the past 10,000 years B.P., which are mainly shown as follows:
The temperature and sea level went up again at high speed, the trench valleys were filled up quickly by deposits, the glaciers shrank, the frozen ground moved north ward or upward, the forests expanded and broad-leaved trees increased during 10, 500 -9, 000aB.P.
A higher temperature and higher sea level appeared during 9,000-6, 000a.B.P. and in the most suitable environment during 6,000-4, 000a.B.P. appeared a series of environ- mental changes, such as the alternation of new higher temperature and new glacial period, the expansion of evergreen broad-leaved forest in subtropics, the movement of coniferous forests from north to south, the enrichment and lacunas of micropalaeobio-logy fond of warm climate- foraminiferal fossils, the increase and decrease of precipitation, the development and stagnation of peat, etc.
For the past 4,000a.B.P., there has been an environment in which the temperature and sea level tended to fall, the climate became warm and dry, the evergreen broad-le-aved trees reduced, the river mouths moved outward because of the falling of the sea level, the trench valleys were cut again, the land surface was seriously washed, secondary loess was accumulated, the frequency of the climatic undulation was quickened , the change ranges were weakened and the environment went bad.
出处
《贵州地质》
1989年第3期227-238,共12页
Guizhou Geology
