摘要:
通过对已有38个剖面的孢粉时间序列分析,探讨了1.6MaBP~0.8MaBP的植被与环境巨变,划分出两个孢粉带及两个孢粉气候事件,提出该时段是更新世环境最恶劣的时期。该时期植被稀疏,北方一般以森林草原和草原为主,西北地区出现荒漠或荒漠草原,南方以森林及灌丛草原为主,表明当时气候冷干,降温幅度可达15~17℃,降水量减少300~500mm.这一环境变化使得亚热带树种再也没有返回华北及其以北地区,从而形成了现今植被分布的雏形。此后的植物群波动也发生了变革,波动幅度加大,波动频率增高。柴达木盆地云杉花粉的变化证实,此时青藏高原已上升到足以使植被状态发生转型的高度。
Abstract:
By an analysis of the sporopllen time sequences from samples of 38 sections, a discussion of the vegetational and environmental megaevolution in China during the time of 1.6MaBP~0.8MaBP was made, with the result that we have 2 zones of the sporopollen assemblages and 2 palynoclimate events. It is pointed out that it was the period of the worst environment in the pleistocene, during which vegetation was very sparse, with dominantly forest-steppe and steppe in northern China, desert or desert-steppe in northwestern China and forest and shrub-steppe in southern China. It has been shown that the climate was then cold and dry, with a of 15~17℃ temperature drop and decrease En precipitation of 300~500mm. As a result no reappearance of subtropical plant has since occurrred in North China and further north, but an initial form of the present vegetation cover. There after there was a more frequent and larger flora fluctuation. The change of spruce pollen in Qaidam Basin shows that the Qinghai-Tibetan Plateau had then been uplifted to a height that could cause a transformation of the vegetation.
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