The hyperarid Atacama Desert is one of the driest and oldest deserts on Earth, rendering it a valuable climate archive. However, unraveling its past climate is particularly challenging and the few studied paleoclimate records of the region reveal strong temporal and spatial variabilities. To enhance our understanding of these dynamics we investigated a sedimentary record in the Yungay valley located in the southern hyperarid Atacama Desert. We employed paleomagnetic and radiocarbon dating, and for the first time for Atacama Desert sediments, a meteoric 10Be/9Be based method for determining the depositional age. The respective 4.20 m deep profile comprises a lower alluvial fan deposit with a maximum age of 3.8 ± 0.8 Ma, and an upper 1.84 m thick clay pan deposit that has accumulated over the last 19 ka. Different proxies including grain size, salt concentration, and elemental composition indicate an aridity increase around 2.3 Ma ago and repeated dry and wet phases during the late Pleistocene and the Holocene. The latter climatic shifts can be assigned to variabilities of the South American Summer Monsoon and El Niño Southern Oscillation with moisture sources from the Atlantic and the Pacific Ocean, respectively. This study provides deeper insights into the heterogeneous climate of the hyperarid Atacama Desert and underlines the importance of interdisciplinary investigations to decipher climate systems and their effect on potential habitable regions in such an extreme environment.

中文翻译：

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极度干旱的阿塔卡马沙漠 3.8 Ma 沉积记录中的气候变化


极度干旱的阿塔卡马沙漠是地球上最干燥、最古老的沙漠之一，使其成为宝贵的气候档案。然而，解开其过去的气候尤其具有挑战性，对该地区的少数研究古气候记录揭示了强烈的时间和空间变化。为了加深对这些动态的理解，我们调查了位于极度干旱的阿塔卡马沙漠南部云盖山谷的沉积记录。我们采用了古地磁和放射性碳测年法，并首次针对阿塔卡马沙漠沉积物采用了基于大气 10Be/9Be 的方法来确定沉积年龄。各自深 4.20 m 的剖面由最大年龄为 3.8 ± 0.8 Ma 的下部冲积扇沉积物和过去 19 ka 积累的上部 1.84 m 厚的粘土盘沉积物组成。包括粒度、盐浓度和元素组成在内的不同指标表明，2.3 Ma 前的干旱程度有所增加，并且在晚更新世和全新世期间出现了重复的干湿阶段。后者的气候变化可归因于南美夏季季风和厄尔尼诺南方涛动的变化，其水分来源分别来自大西洋和太平洋。这项研究为极度干旱的阿塔卡马沙漠的异质气候提供了更深入的见解，并强调了跨学科研究对于破译气候系统及其对这种极端环境下潜在宜居区域的影响的重要性。