Figure 6: Provenance data from the Honggou section and potential source regions.

(a) Apatite fission track (AFT) population peak ages plot for samples from the Honggou section. Error bars are ±2σ for apatite FT ages. P1, P2 and P3 represent the youngest, second youngest and third population peak ages, respectively. The dark to light lines show the youngest, second youngest and third population peak ages trend with sedimentary ages of the samples. (b–j) Zircon U-Pb age cumulative probability distributions from the Qilian Shan (b), East Kunkun Shan (j) and the Honggou section (c–i). For the zircon U-Pb age plots, the blue rectangles are 180–350 Myr ago zircon grain histograms, whereas the red rectangles are 350–500 Myr ago zircon grain histograms. The colour change from blue to red in vertical shade areas represents source variation. The sedimentary ages of the samples are based on the Honggou magnetostratigraphy.