1Alfred Wegener Institute for Polar and Marine Research, Telegrafenberg A43, 14473 Potsdam, Germany
2Freie Universität Berlin, Institute of Geological Sciences, Malteserstrasse 74-100, 12249 Berlin, Germany
3University of Potsdam, Department of Geosciences, Potsdam, Germany
4Lanzhou University, Centre for Arid Environment and Paleoclimate Research, Tianshui Road 298, Lanzhou 730000, China