摘要
洛川地区倒数第二次间冰期磁化率与孢粉资料分析表明:248.1~236.1 ka BP气候温暖湿润,236.1~215.4 ka BP气候变得相对干冷;215.4~188.7 ka BP为该时期最湿热的阶段,其年均温比现今高5℃左右,年均降水量高300 mm左右。洛川地区气候变化与全球性气候变化具有一致性,但也存在地区差异。S2-1包括孢粉Ⅴ、Ⅵ带,对应于MIS7a的湿热期,S2-2包括孢粉带Ⅱ、Ⅲ、Ⅳ,对应于MIS7b^7d气候转为干冷期,S2-3与孢粉带Ⅰ和MIS7e相一致,其中在S2-2阶段,223.2~218.7 ka BP时期的增温事件与孢粉Ⅲ带和MIS7c相对应。黄土高原地区各剖面磁化率特征表现出极高的一致性,而与东部沿海地区存在着一些差异,原因可能是季风三角的不同地区受夏季风的影响强弱不同造成的。
The climate change sequence during the penultimate Interglacial in Luochuan area was established through analysis on the vertical variations of magnetic susceptibility and sporo-pollen in strata. From 248.1 to 236.1 ka BP, the climate was warm and wet; from 236.1 to 215.4 ka BP, the climate became relatively drought and cold; from 215.4 to 188.7 ka BP the climate was the most humid and hot of the penultimate Interglacial, with annual average temperature of 5℃ and annual average precipitation of 300 mm more than that at present. The characteristics of climate change in the study region are coincident with that of the global climate change except for some difference among sub-regions. The sub-paleosol-layer of S2-1 corresponds to the Ⅴ and Ⅵ sections of sporo-pollen spectrum, and to the humid-hot stage during MIS-7a; the S2-2 to the Ⅱ, Ⅲ, and IV sections, and to the cold-dry stage during MIS-Tb, c, d; the S2-3 to the Ⅰ section and the MIS7-e stage. In detail, the temperature-increasing-event during 223.2--218.7 ka BP recorded by S2-2 corresponds to the Ⅲ section and the MIS7-c stage. The magnetic susceptibility sequences in different profiles of the Loess plateau show highly coincident but are different from than those in profiles at east littoral, which may be resulted form difference of the summer monsoon strength.
出处
《中国沙漠》
CSCD
北大核心
2009年第3期536-543,共8页
Journal of Desert Research
基金
北京市教委科技发展基金重点项目
北京地区25万年来的环境演化集成研究(KZ200810028015)
关键词
洛川
S2
磁化率
孢粉
Luochuan profile
S2 paleosol
magnetic susceptibility
sporo-pollen
