13 ka BP以来黄土高原西部的植被与环境演化

Vegetation and Climate Changes in the Western Part of the Loess Plateau since 13 ka BP

通过对黄土高原西部三个剖面的孢粉记录分析,重建了该区13kaBP以来详细的植被与气候演化序列。结果表明,12.1kaBP以前,研究区植被以干草原为主,气候寒冷干燥。12.1-9.8kaBP植被变化显著。期间出现两次显著的湿润期,分别为12.1-11.4kaBP、11.2-11.0kaBP,可与博令暖期和阿勒罗得暖期对比;两次持续时间和强度明显不同的干旱期出现在11.4-1.2kaBP和11.0-9.8kaBP,可分别与中仙女木事件和新仙女木事件对比。经过短暂的快速变湿后,9.6-7.6kaBP研究区植被以疏林草原为主,气候波动频繁但总体温和偏干。7.6-4.0kaBP森林和森林草原植被出现,气候温暖湿润。其中6.6-5.8kaBP温带落叶阔叶林发育,为研究区全新世最适宜期。自4.0kaBP以来研究区草原和荒漠草原交替出现,气候在总体干冷的环境下存在次一级的干湿波动。

Sporo-pollen records from the western part of Chinese Loess Plateau revealed a detailed history of vegetation variation and associated climate changes since 13 ka BP. Before 12.1 ka BP, steppe or desert-steppe vegetation dominated landscape, which was then replaced by a coniferous forest under a generally wet climate （12.1-11.0 ka BP）. The vegetation was degenerated into steppe landscape and further into a desert-steppe landscape from 11.0 to 9.8 ka BP. After a brief episode of a cool and wet climate （9.8-9.6 ka BP）, a relatively mild and dry condition prevailed during the early Holocene （9.6-7.6 ka BP）. The most favourable climate of warm and humid period occurred during mid-Holocene （7.6-4.0 ka BP） marked by forest-steppe landscape, and an alternation of steppe and desert-steppe has occurred since ～4.0 ka BP.