loop may be interpreted as a magnetic mineralogical signature,
the height of a loop is a function of concentrations and
types of magnetic minerals in a natural sample, and the
width of a loop is entirely controlled by the coercivity of
minerals [37]. Hysteresis loops for typical samples with
their corresponding hysteresis parameters are depicted in
Figure 3. The magnetization increases rapidly with the
magnetic field strength increase before 200 mT. The magnetization
almost always saturates when the applied magnetic
field reaches 250 mT, and the Bc of the representative
samples ranges from 9 to 11 mT, indicating that the magnetic
minerals are dominated by low coercivity ferrimagnets
(predominantly magnetite).