backfield remagnetization of SIRM was performed, the result
of which was used to calculate the coercive force of remanence
(Bcr) by means of linear interpolation, as well as to
calculate HIRM, SOFT, ARM/SIRM and S-ratio (IRM300 mT/
SIRM). Magnetic hysteresis loops (content Ms, Mrs, Bc,
maximum field is 1 T) and thermomagnetic curves (heating
and cooling cycles, which measured from 25 to 700°C by
4°C/s in 100 mT magnetic field, were performed in open air)
were determined using a variable field translation balance
(VFTB). Magnetic parameters were measured in the Key
Laboratory of Western China’s Environmental System,
Lanzhou, China.