A catalogue of calcite vein types in porous sandstone and their formation conditions (Huab Basin, Namibia)

A catalogue of calcite vein types in porous sandstone from the UNESCO World Heritage Site Twyfelfontein (Namibia) reveals insights into fluid flow dynamics and climatic shifts over millions of years. The study identifies distinct calcite vein formations, including blocky, radial, and micritic structures, some intergrown with kaolinite or preceded by dolomite and iron oxide precipitation. U-Pb dating indicates most veins formed between 31 million years ago (Ma) to the present, with one outlier at ~65 Ma, while clumped isotope analysis suggests shallow burial depths (< 1 km) during formation, except for a high-temperature outlier linked to the older vein. Carbonate δ13C values show a trend from -8.3‰ to -1.3‰, reflecting a shift from warm, humid to (semi-)arid conditions in the region. The research suggests this climatic change is responsible for many observed vein characteristics, providing a link between geological processes and environmental evolution.

Salomon, E., Meckler, A. N., Gerdes, A., Albert, R., & Stollhofen, H. (2025). A catalogue of calcite vein types in porous sandstone and their formation conditions (Huab Basin, Namibia). Journal of Structural Geology, 200, 105506. https://doi.org/10.1016/j.jsg.2025.105506