Fig. 3

a, b Variations of the two ratios, χ _ARM/χ and χ _ARM/SIRM (in depth). c–f The FORC diagrams of the studied samples which obtained at 0.59, 6.97, 21.21, and 21.81 m core depth. The red lines mark the locations where the four samples were selected and the smoothing factors (SF) are given in the diagrams, respectively