LI, Su, School of Earth Sciences, Lanzhou University, No.222 Tianshui South Road, Chengguan Area, Lanzhou, 730000, China, RUDNICK, Roberta, Department of Earth Science and Earth Research Institute, University of California Santa Barbara, Santa Barbara, CA 93106, QIU, Lin, IVL Swedish Environmental Research Institute, Shanghai, China, ZURKOWSKI, Claire, Department of the Geophysical Sciences, University of Chicago, Chicago, 60637, GASCHNIG, Rich, Department of Environmental, Earth and Atmospheric Sciences, University of Massachusetts Lowell, 1 University Dr, Lowell, MA 01854, VALLEY, John, Department of Geoscience, University of Wisconsin-Madison, 1215 W Dayton Street, Madison, WI 53706, GUY, Bradley M., Department of Geology, University of Johannesburg, Auckland Park, 2006, South Africa and BEUKES, Nicolas J., Department of Geology, University of Johannesburg, P.O. Box 524, Auckland Park, Johannesburg, 2006, South Africa