Magnetic mineralogical applications of stepwise heating κ-T experiments

Magnetic mineral identification plays an important role in mineral pre-census as well as in the study of mineralization patterns. Conventional magnetic mineral identification experiments（magnetization versus temperature, called κ-T experiment） usually use a single-cycle heating-cooling mode from room temperature to 700 ℃, which lacks a capture point for the characteristics of the magnetic susceptibility changes in the intermediate temperature cycles. To address this deficiency, a stepwise heating κ-T experiment is designed in this paper to detect the transformation process of magnetic minerals in different heating stages, providing a reliable basis for the accurate identification of magnetic mineral species. In this paper, the results of the stepwise heating κ-T experiments are validated and supplemented with the rock magnetism experiments, such as isothermal remanent magnetization（IRM） and demagnetization（J/J_max）, as well as scanning electron microscopy（SEM） and energy spectrum analysis（EDS） experiments. The experimental results show that the stepwise heating κ-T experiments can provide the details of magnetic mineral transformation that are missing in the traditional κ-T experiments, and combined with the coercivity characteristics, the blocking temperature, and the SEM and EDS results, the magnetic mineral types of the geological samples can be clearly identified.