Dataset of Thermomagnetic Curves, Hysteresis parameters and Sample Coordinates from Soil Studies in Eastern Botswana

This study hypothesizes that the magnetic properties of soils and rocks in eastern Botswana—specifically thermomagnetic and hysteresis parameters—can reveal mineralogy, geological history, and environmental conditions. Parameters like Curie temperature, magnetic susceptibility, and hysteresis traits help identify minerals such as magnetite, hematite, pyrrhotite, and titanomagnetite, and their grain sizes. These signatures enable mapping of geological units, boundaries, and mineral formation processes influenced by tectonics and past environments.

Samples were collected from soils (5–30 cm depth) along roads during the dry season, stored in plastic containers to prevent contamination. Rocks came from outcrops and quarries. Laboratory analysis involved heating samples up to 700 °C in nitrogen to identify Curie temperatures, and measuring hysteresis parameters (Mrs, Ms, Hcr, Hc) to assess mineral grain size and domain states.

Results show most samples contain magnetite-like minerals with Curie temperatures near 585 °C. Some exhibit secondary features like Hopkinson peaks, indicating mineral mixes such as hematite and pyrrhotite. Mineral alterations, like magnetite oxidation to hematite, are evident from susceptibility changes. Hysteresis data reveal a range of grain sizes and magnetic domain states, reflecting geological processes like weathering and neoformation. Non-reversible heating/cooling behavior suggests metastable minerals or alteration during thermal treatment.

Geologically, magnetic variations support mapping of features like the Kaapvaal and Zimbabwe Cratons and the Limpopo Belt. The data confirm regions dominated by magnetite minerals, useful for mineral exploration, paleoenvironmental reconstruction, and regional tectonic mapping. Overall, combining thermomagnetic and hysteresis measurements provides insights into mineralogy, alteration pathways, and geological structures essential for exploration and environmental assessments.