Loess‐Like Dust Appearance at 40 Ma in Central China
Dupont‐Nivet, Guillaume
Barbolini, Natasha
Woutersen, Amber
Rohrmann, Alexander
Zhang, Yang
Liu, Xiang‐Jun
Licht, Alexis
Abels, Hemmo A.
Hoorn, Carina
Tjallingii, Rik
Andermann, Christoff
Dietze, Michael
Nowaczyk, Norbert
DOI: https://doi.org/10.23689/fidgeo-4379
Barbolini, Natasha; 4 Department of Ecology Environment and Plant Sciences and Bolin Centre for Climate Research Stockholm University Stockholm Sweden
Woutersen, Amber; 5 Department of Ecosystem and Landscape Dynamics (ELD) Institute for Biodiversity and Ecosystem Dynamics (IBED) University of Amsterdam Amsterdam The Netherlands
Rohrmann, Alexander; 6 Institute of Geological Sciences Freie Universität Berlin Berlin Germany
Zhang, Yang; 3 Key Laboratory of Orogenic Belts and Crustal Evolution Ministry of Education School of Earth and Space Sciences Peking University Beijing China
Liu, Xiang‐Jun; 7 College of Geography and Environmental Science Northwest Normal University Lanzhou China
Licht, Alexis; 8 Department of Earth and Space Sciences University of Washington Seattle WA USA
Abels, Hemmo A.; 9 Department of Geosciences and Engineering Delft University of Technology Delft The Netherlands
Hoorn, Carina; 5 Department of Ecosystem and Landscape Dynamics (ELD) Institute for Biodiversity and Ecosystem Dynamics (IBED) University of Amsterdam Amsterdam The Netherlands
Tjallingii, Rik; 10 GFZ German Research Centre for Geosciences Potsdam Germany
Andermann, Christoff; 10 GFZ German Research Centre for Geosciences Potsdam Germany
Dietze, Michael; 10 GFZ German Research Centre for Geosciences Potsdam Germany
Nowaczyk, Norbert; 10 GFZ German Research Centre for Geosciences Potsdam Germany
Abstract
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.