Holocene non-orbital climatic events in present-day arid areas of northern Africa and China
Holocene non-orbital climatic events in present-day arid areas of northern Africa and China
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DOI：
10.1016/s0921-8181(00)00037-0
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发表时间：
2000-11-01
影响因子：
3.9
通讯作者：
Kröpelin, S
中科院分区：
文献类型：
--
作者：
Guo, ZT;Petit-Maire, N;Kröpelin, S
通过对北方非洲干旱区和中国北方干旱区气候演变的初步比较，发现在10（4）年时间尺度上，近14万年来大陆干旱度的变化基本同步。这种关系是否可以建立在一个世纪的尺度上的全新世干旱事件，如报告的热带和赤道非洲，仍然是未知的。通过对撒哈拉沙漠560个地表淡水指标的放射性碳测年与中国北方干旱区158个古土壤和湖泊沉积物的对比研究，表明两个地区全新世湿润阶段都受到了几次干旱事件的影响，镶嵌在轨道强迫的缓慢趋势中。这些指标随时间的纬度分布记录了与北方季风锋有关的沙漠南缘的变化。最令人吃惊的是，在距今7000年至5600年之间，出现了一段较长的、稍显干燥的时期，而在公元前2000年左右，开始出现严重的干旱。距今4000年，与冰川条件相似。(C)2000 Elsevier Science B.V.保留所有权利。
A preliminary comparison between the climatic evolution of the arid regions in northern Africa and northern China showed that the variations in continental aridity, on time scales of 10(4) years, were roughly synchronous over the last 140 ka. Whether this relationship can be established for the Holocene drought events on a century-scale, as reported for tropical and equatorial Africa, is still not known. The comparison of 560 radiocarbon dates on surface fresh water indicators from the Sahara with 158 dates on palaeosols and lake sediments from the arid regions in northern China demonstrates that the Holocene humid phase has been affected in both regions by several drier events, inlaid in the slow trend attributable to orbital forcing. The variations of the southern margins of the deserts, associated with the northern monsoon front, are documented by the latitudinal distribution of these indicators through time. The most startling aspects are a prolonged somewhat drier interval between 7000 and 5600 years BP and the onset of severe aridity at c. 4000 years BP similar to glacial conditions. (C) 2000 Elsevier Science B.V. All rights reserved.