In general, both lower ARM/ and ARM/SIRM indicate
coarse grains of magnetite, while higher ratios indicate fine
grains, especially SD grains. The ARM/ ratio depend on
the magnetic minerals composition and magnetic particle
size [15,34]. ARM/ and ARM/SIRM values are 2.1 and
0.18×103 m A1 respectively, and the values below the
background imply the contribution of predominant coarse
magnetic particles. ARM/ (Figure 4(g)) and ARM/SIRM
(Figure 4(h)) possess variations similar to fd%.
S-ratio represents of the relative amounts of high-coercivity
(“hard”) remanence to low-coercivity (“soft”) remanence.
In many cases, this allows a fairly accurate estimation
of the relative incidence of antiferromagnetic versus
ferrimagnetic materials. Samples with a high S-ratio primarily
contain magnetite; lower values indicate contributions of
“harder” magnetic minerals. The mean S-ratio value of the
samples is 0.93, ranging from 0.85 to 0.97, indicating that
the dominant magnetic component is ferrimagnetic minerals.
The mean value of Bcr is 40.78 mT, ranging from 26.65 to
51.94 mT, and the low value of Bcr further indicates that
low-coercivity (“soft”) minerals (such as magnetite) dominate
the magnetic component.