Fig. 1. The distribution map of collected and studied drill cores

Fig. 2. Grain size histograms of mottled clay and comparison with those of underlying layers and typical loess(Plotted with average values in Table 1)

Fig. 3. Scatter diagrams of grain size parameters of mottled clay and comparison with those of underlying layers and typical loess
As lack of Kg data, no points of Luochuan loess and Zhenjiang Xiashu loess present in Fig.(c, e, f), others from [5-6]; Data of Xifeng loess from [8])

Fig. 4. Discriminant analysis of mottled clay and comparison with those of underlying layers and typical loess (Data of Xifeng loess from [8])

Fig. 5. Grain size indices of mottled clay and comparison with those of underlying layers and typical loess (Data of Xifeng loess from [8])

Fig. 6. Grain size facies of mottled clay and comparison with those of underlying layers and typical loess (Scope of the typical loess from [8])