Aeolian Dust Preserved in the Guliya Ice Cap (Northwestern Tibet): A Promising Paleo-Environmental Messenger
Aeolian Dust Preserved in the Guliya Ice Cap (Northwestern Tibet): A Promising Paleo-Environmental Messenger
复制标题
DOI：
10.3390/geosciences12100366
复制
发表时间：
2022-09
期刊：
影响因子：
2.7
通讯作者：
Roveri Marco;Jesus Martinez-Frias;E. Beaudon;J. Sheets;E. Martin;Roxana Sierra-Hern á ndez;E. Mosley‐Tho
中科院分区：
文献类型：
--
作者：
Roveri Marco;Jesus Martinez-Frias;E. Beaudon;J. Sheets;E. Martin;Roxana Sierra-Hern á ndez;E. Mosley‐Tho
亚洲风尘是影响北方大气动力学的主要因素。预测大气环流模式过去和未来的变化部分依赖于对中亚尘埃特性和尘埃循环的充分了解。不幸的是，该地区的数据太少，无法限制灰尘成分随时间的变化。在这里，我们评估了西藏冰芯提供全面的古大气尘埃记录的潜力，从而减少矿物气溶胶对气候系统的反馈的不确定性。我们提出了第一个数据集的矿物学，地球化学和Sr-Nd同位素组成的风成尘埃保存在前全新世层的两个冰芯从古里雅冰帽（昆仑山）。来自Summit（GS; 6710 m a.s.l.）的样品组成和高原（GP;海拔6200米）核心揭示了核心最深冰层中尘埃的特征是显着不同的。最深的GS层揭示对应于来自塔克拉玛干沙漠的风成颗粒的同位素值，包含细颗粒和粗颗粒的混合物，并且包括暗示在源处的干燥气候的气候敏感材料。深GP层主要由不寻常的结核以及大小分选灰色粘土富含耐风化的矿物和元素通常在地热沃茨中发现，这表明保存在最古老的GP层的灰尘来自潮湿和可能缺氧的来源。这里强调的灰尘成分的变化证明了其作为古环境信使的相关性，并保证进一步探索特别异质的古里雅冰川灰尘档案。
Asian aeolian dust is a primary factor in Northern Hemisphere atmospheric dynamics. Predicting past and future changes in atmospheric circulation patterns relies in part on sound knowledge of Central Asian dust properties and the dust cycle. Unfortunately for that region, data are too sparse to constrain the variation in dust composition over time. Here, we evaluate the potential of a Tibetan ice core to provide a comprehensive paleo-atmospheric dust record and thereby reduce uncertainties regarding mineral aerosols’ feedback on the climate system. We present the first datasets of the mineralogical, geochemical, and Sr-Nd isotope composition of aeolian dust preserved in pre-Holocene layers of two ice cores from the Guliya ice cap (Kunlun Mountains). The composition of samples from the Summit (GS; 6710 m a.s.l.) and Plateau (GP; 6200 m a.s.l.) cores reveals that the characteristics of the dust in the cores’ deepest ice layers are significantly different. The deepest GS layers reveal isotopic values that correspond to aeolian particles from the Taklimakan desert, contain a mix of fine and coarse grains, and include weathering-sensitive material suggestive of a dry climate at the source. The deep GP layers primarily consist of unusual nodules of well size-sorted grey clay enriched in weathering-resistant minerals and elements typically found in geothermal waters, suggesting that the dust preserved in the oldest GP layers originates from a wet and possibly anoxic source. The variability of the dust composition highlighted here attests to its relevance as a paleo-environmental messenger and warrants further exploration of the particularly heterogenous Guliya glacial dust archive.