Fig. 1. Location of Qiangyong Co Lake

Fig. 2. Environmental magnetic parameters and mercury (Hg) concentrations of Qiangyong Co Lake (the Hg concentration and Qiangyong chronology are from Kang et al., 2016)

Fig. 3. Day-plot (a), magnetic hysteresis loops (b), isothermal remnant magnetization (IRM) acquisition curves (c), and backfield demagnetization curves (d) of Qiangyong Co Lake

Fig. 4. Saturation isothermal remnant magnetization (SIRM) (a), Unmixing of IRM acquisition curves (b-g), First-order reversal curves (FORCs) (h-j) and χ-T (k-m) of typical samples

Fig. 5. Zero-field-cooling (ZFC) curves (a, the solid and dashed lines represent the origin data and first derivative data of the ZRC curves, respectively) and the second derivative curves of diffuse reflectance spectroscopy (DRS) (b) for selected samples from Qiangyong Co Lake

Fig. 6. Correlations between the variations of magnetic components and mercury (Hg) concentration in Qiangyong Co Lake and environmental indexes (annual average precipitation and temperature) of Nagarze station

Fig. 7. The variations of different magnetic components of Qiangyong Co Lake (a-d), annual precipitation (e), average temperature from Nagarze station (f), temperature anomaly of the Tibetan Plateau and the Northern Hemisphere (g), and Hg concentration (h) (the Hg concentration and Qiangyong chronology are from Kang et al., 2016; the temperature anomaly of the Tibetan Plateau and the Northern Hemisphere)