A Hydrochemical Method for Identifying Orbital Imprints of Dust in Paleofluvial Sequences

作者：Zhongyi Yan, Yibo Yang, Wenxia Han, Yudong Liu, Xiaoming Liu, Xiaomin Fang · 发表于：Geophysical Research Letters · 年份：2024 · DOI：10.1029/2024gl109988 · 被引用次数：3 · 研究领域：Geology and Paleoclimatology Research、Aeolian processes and effects、Astro and Planetary Science

Abstract Mineral dust plays an important role in Earth's climate system, yet it is difficult to identify dust imprints in paleofluvial sediments, especially on orbital timescales. Here, we present high‐resolution authigenic carbonate Ca–Mg–Sr compositions in a fluvial sequence under the transport pathway of Asian dust. The Mg/Ca, Sr/Ca, and Mg/Sr ratios exhibit distinct transitions in both secular trends and orbital cycles at ∼8 Ma. Before ∼8 Ma, given similar Mg and Sr partitioning behaviors during carbonate formation, hydroclimate changes yielded strong orbital signals in the Sr/Ca and Mg/Ca ratios but no detectable signals in the Mg/Sr ratios. After ∼8 Ma, given the strengthened input of Mg‐rich dust during cold‒dry periods, the Mg/Sr and Mg/Ca ratios clearly exhibited orbital signals, but the Sr/Ca ratio did not. Such transitions in carbonate composition corroborate the dust‐induced changes in fluvial hydrochemistry, offering an innovative methodology for detecting orbital dust cycles in paleofluvial systems.