Loess‐Like Dust Appearance at 40 Ma in Central China

Media type: E-Article

Title: Loess‐Like Dust Appearance at 40 Ma in Central China

Contributor: Meijer, Niels [Author]; Dupont‐Nivet, Guillaume [Author]; Barbolini, Natasha [Author]; Woutersen, Amber [Author]; Rohrmann, Alexander [Author]; Zhang, Yang [Author]; Liu, Xiang‐Jun [Author]; Licht, Alexis [Author]; Abels, Hemmo A. [Author]; Hoorn, Carina [Author]; Tjallingii, Rik [Author]; Andermann, Christoff [Author]; Dietze, Michael [Author]; Nowaczyk, Norbert [Author]; 1 Institute for Geosciences Universität Potsdam Potsdam Germany [Author]; 4 Department of Ecology Environment and Plant Sciences and Bolin Centre for Climate Research Stockholm University Stockholm Sweden [Author]; 5 Department of Ecosystem and Landscape Dynamics (ELD) Institute for Biodiversity and Ecosystem Dynamics (IBED) University of Amsterdam Amsterdam The Netherlands [Author]; 6 Institute of Geological Sciences Freie Universität Berlin Berlin Germany [Author]; 3 Key Laboratory of Orogenic Belts and Crustal Evolution Ministry of Education School of Earth and Space Sciences Peking University Beijing China [Author]; 7 College of Geography and Environmental Science Northwest Normal University Lanzhou China [Author]; 8 Department of Earth and Space Sciences University of Washington Seattle WA USA [Author]; 9 Department of Geosciences and Engineering Delft University of Technology Delft The Netherlands [Author]; 10 GFZ German Research Centre for Geosciences Potsdam Germany [Author]

imprint: GEO-LEOe-docs (FID GEO), 2021-03-01

Language: English

DOI: https://doi.org/10.23689/fidgeo-4379

Keywords: aridification ; loess ; dust ; middle Eocene ; Siberian High ; winter monsoon

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Description: Asian mineral dust has been studied extensively for its role in affecting regional‐to global‐scale climate and for its deposits, which enable reconstructing Asian atmospheric circulation in the past. However, the timing and origin of the dust deposits remain debated. Numerous loess records have been reported across the Asian continent with ages varying from the Miocene to the Eocene and linked to various mechanisms including global cooling, Tibetan Plateau uplift and retreat of the inland proto‐Paratethys Sea. Here, we study the Eocene terrestrial mudrocks of the Xining Basin in central China and use nonparametric end‐member analysis of grain‐size distributions to identify a loess‐like dust component appearing in the record at 40 Ma. This is coeval with the onset of high‐latitude orbital cycles and a shift to predominant steppe‐desert vegetation as recognized by previous studies in the same record. Furthermore, we derive wind directions from eolian dune deposits which suggest northwesterly winds, similar to the modern‐day winter monsoon which is driven by a high pressure system developing over Siberia. We propose that the observed shifts at 40 Ma reflect the onset of the Siberian High interacting with westerly derived moisture at obliquity timescales and promoting dust storms and aridification in central China. The timing suggests that the onset may have been triggered by increased continentality due to the retreating proto‐Paratethys Sea. ; Key Points: The onset of Asian dust is identified at 40 Ma within a longer continuous record. Shifts in the dust, cyclostratigraphy and pollen suggest the Siberian High at 40 Ma. The coeval proto‐Paratethys Sea retreat triggered the onset of the Siberian High. ; EC, H2020, H2020 Priority Excellent Science, H2020 European Research Council (ERC) http://dx.doi.org/10.13039/100010663

Access State: Open Access

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