Supplementary Figure 1

Lithostratigraphic units and ages from the closed basins of the Qilian Mountains (14C ages are shown on the right side of the profile, unit: cal yr BP) "

Figure 1

Elevation map of the closed basins in the Qilian Mountains (upper map), and maps showing sampling points in the river basins of Shiyang (a), Fengle (b), Shiyou (c), and Buha (d) (lower maps)"

Supplementary Table 1

Basic physical and chemical date, radiocarbon result, and corrected age of the groundwater samples in the Shiyang, Fengle, Shiyou and Buha river basins "

Figure 2

Groundwater ages of the Shiyang River basin, the Fengle River basin, the Shiyou River basin, and the Buha River basin (left) and groundwater isotopes from the four rivers (right)"

Figure 3

Locations of the results of the discriminant analysis along discriminant functions 1 and 2"

Figure 4

TOC, δ 13Corg, δ 13Cinorg, δ 18Oinorg, and median grain-size from surface samples versus elevations of the Shiyang River basin, the Fengle River basin, the Shiyou River basin, and the Buha River basin "

Supplementary Table 2

Paleoclimatic records used in this study "

Figure 5

Results of PCA in the closed basins of the Qilian Mountains during the Holocene. The orange lines are the PCA1 without 6770-12000 cal yr BP data; the blue lines are the PCA1 without 0-1057 cal yr BP data"

Figure 6

Results of global PCA during the Holocene. The orange lines are the PCA1 without 6000-12000 cal yr BP data; the blue lines are the PCA1 without 0-6000 cal yr BP data (BP means before present, in radiocarbon dating; the present is the calendar date for the year 1950 AD.)"

Figure 7

Land use map of the Shiyang River basin, the Fengle River basin, the Shiyou River basin, and the Buha River basin. WESTDC-land-cover-products 2.0. data come from the Data Center for Environmental and Ecological Sciences in Western China (http://westdc.westgis.ac.cn), of the National Natural Science Foundation of China "

Figure 8

Comparison of PCA results for the closed basins of the Qilian Mountains and for other climatic records during the Holocene. δ 18O of the stalagmite from Dongge Cave (Dykoski et al. 2005); trends of precipitation/moisture evolution indicated by the χ ARM/SIRM ratio of the LJW10 Holocene paleosol section (Chen et al. 2016); summer insolation and winter insolation (Berger et al. 1978) "

Figure 9

Comparison of results of PCA in global closed basins and other climatic records during the Holocene. Arid Central Asia moisture index (Chen et al. 2008); δ 18O record from the GISP ice core, Greenland (Stuiver et al. 1995) "