Speleothem growth phases in the central Eastern Desert of Egypt reveal enhanced humidity throughout MIS 5
Speleothem growth phases in the central Eastern Desert of Egypt reveal enhanced humidity throughout MIS 5
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DOI：
10.1016/j.quaint.2021.05.006
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发表时间：
2021-05
影响因子：
2.2
通讯作者：
F. Henselowsky;R. Eichstädter;A. Schröder‐Ritzrau;D. Herwartz;Ahmed A. Almoazamy;N. Frank;Karin Kindermann
中科院分区：
文献类型：
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作者：
F. Henselowsky;R. Eichstädter;A. Schröder‐Ritzrau;D. Herwartz;Ahmed A. Almoazamy;N. Frank;Karin Kindermann
当今干旱环境中的洞穴沉积物是重要的气候档案，因为它们表明了降水增强的阶段，并且可以通过铀系测年来精确测定年代。到目前为止，在当今极度干旱的撒哈罗-阿拉伯沙漠（SAD）中只发现了很少的此类档案。因此，这项研究填补了东北非洞穴气候档案的空白。萨奇亚洞穴（埃及中东部沙漠）的一项新记录记录了埃及首次在 MIS 5 的所有子阶段和 MIS 6 期间的奇异阶段中发现洞穴生物的生长。最重要的生长阶段发生在北半球日照强烈增加和最大轨道强制日照期间，但也发生在低日照阶段，这通常归因于北非的干旱。在这里，对于 MIS 5 的低日照期间，至少提出了半干旱气候条件。这表明，除了非洲季风的大规模变化（例如红海槽、热带李子和地中海冬季降雨区的更大空间范围）之外，不同可能的降水来源的影响。关于埃及的空间降雨模式，我们提出相当大的从东到西的降雨模式 埃及末次间冰期的降雨梯度表明，与埃及西部沙漠相比，地中海和红海附近的东部沙漠的可变水分源的影响更大。这揭示了过去增强土地利用潜力的更有利的先决条件。因此，东部沙漠更加持续的湿润气候表明，在整个 MIS 5 期间，智人从热带气候到温带气候的反复出现的可行扩散走廊。这种更加潮湿的气候为尼罗河谷以东的长期、有利的环境条件提供了理想的基础，创造了一种可能对人类和野生动物都有吸引力的连续景观走廊，将东部连接起来。 非洲热带气候与东北非和欧亚大陆的温带气候。
Speleothem deposits in nowadays arid environments are important climate archives, as they indicate phases of enhanced precipitation and can precisely be dated by uranium-series dating. So far only very few of such archives have been found in the today hyper-arid Saharo-Arabian Desert (SAD). Therefore, the study at hand fills a gap that exists for speleothem climate archives in Northeast Africa. A new record from Saqia Cave (Central Eastern Desert, Egypt) documents for the first-time speleothem growth in Egypt for all sub-stages of MIS 5 and singular phases during MIS 6. Most important growth phases occur during periods of strong increase and maximum orbitally-forced northern hemisphere insolation, but also during phases of low insolation, which are in general attributed to aridity in North Africa. Here, at least semi-arid climate conditions are proposed for periods of low insolation during stadials of MIS 5. This suggests an impact of different possible sources of precipitation, apart from large scale shifts of the African monsoon, such as Red Sea Troughs, tropical plums and a larger spatial extent of the Mediterranean winter-rainfall zone.Concerning the spatial rainfall pattern in Egypt, we propose a considerable east to west rainfall gradient in Egypt for the Last Interglacial and suggest a stronger impact of variable moisture sources in the Eastern Desert near the Mediterranean and Red Sea in comparison to the more continental Western Desert of Egypt. This reveals more favorable pre-conditions for an enhanced land use potential in the past. Therefore, the more sustaining wetter climate in the Eastern Desert point to a recurring feasible dispersal corridor forHomo sapiensfrom the tropical climate into the temperate climate regime throughout MIS 5. Such a more humid climate provided an ideal basis for long-term, favorable environmental conditions east of the Nile Valley, creating a kind of contiguous landscape corridor that may have been attractive to humans and wildlife alike, linking the East African tropical climate regime with that of the temperate zone in Northeast Africa and Eurasia.