Fig. 7

Low-temperature magnetism. a, b Representative thermal demagnetization of low-temperature remanence normalized by the remanence at 300 K of quartz and feldspars (a) and untreated sample (b) from 0.37 m. c Temperature derivative of thermal demagnetization around 120 K highlighting the Verwey transition. Open squares represent untreated samples from 0.37 m (left scale). Solid circles and crosses represent quartz and feldspars from 0.37 and 14.92 m, respectively (right scale). d Depth variation of low-temperature demagnetization behavior of the quartz and feldspars around the Verwey transition. e The graphical explanation for quantification of the demagnetization across the Verwey transition. f The demagnetization across the Verwey transition versus depth. Vertical dashed lines represent lithostratigraphic unit boundaries