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.

本研究提出假说：博茨瓦纳东部的土壤与岩石磁学特性——具体为热磁参数与磁滞参数——可揭示其矿物组成、地质历史与环境状态。诸如居里温度、磁化率及磁滞特征等参数，有助于识别磁铁矿、赤铁矿、磁黄铁矿及钛磁铁矿等矿物及其晶粒尺寸。此类磁学特征可用于绘制地质单元、边界及受构造作用与古环境影响的矿物形成过程分布图。
土壤样本于旱季沿公路采集，采样深度为5–30 cm，储存于塑料容器中以避免污染；岩石样本采自露头与采石场。实验室分析环节包括：在氮气氛围中将样品加热至700 °C以测定居里温度，并测量磁滞参数（剩余磁化强度Mrs、饱和磁化强度Ms、剩磁矫顽力Hcr、矫顽力Hc）以评估矿物晶粒尺寸与磁畴状态。
研究结果显示，绝大多数样品含有类磁铁矿矿物，其居里温度接近585 °C。部分样品呈现霍普金森峰等次生特征，表明存在赤铁矿与磁黄铁矿等矿物混合物；磁化率变化则反映出矿物蚀变现象，例如磁铁矿氧化为赤铁矿。磁滞数据揭示了多样的晶粒尺寸与磁畴状态，反映了风化作用与新生矿物形成等地质过程；加热-冷却过程的不可逆行为则暗示了热处理过程中存在亚稳矿物或矿物蚀变。
从地质学角度而言，磁学变化可辅助绘制卡普瓦尔克拉通、津巴布韦克拉通及林波波带等地质构造。本数据集证实了以磁铁矿为主的区域分布，可用于矿产勘探、古环境重建及区域构造制图。总体而言，结合热磁与磁滞测量手段，可为矿物组成、蚀变路径及地质构造研究提供关键见解，对勘探与环境评估均具有重要价值。