We find that hematite is the main magnetic carrier mineral according to isothermal remanent magnetization acquisition and demagnetization of three orthogonal isothermal remanent magnetization.

We have carried out magnetic cleaning for 619 specimens from 59 sites by A. F and thermal demagnetization.

Secondary viscous remanence (low-temperature component) and primary remanence (high-temperature component) can be effectively separated by thermal-demagnetizing process.