Sandstone Diagenesis in Sediment–lava Sequences: Exceptional Examples of Volcanically Driven Diagenetic Compartmentalization in Dune Valley, Huab Outliers, Nw Namibia

Research at Twyfelfontein, Namibia, reveals three distinct diagenetic styles in fossilized dune sandstones encapsulated by lava flows from the Etendeka flood basalts. Type 1 dunes exhibit red coloring and minimal authigenic mineralization, driven primarily by grain compaction. Type 2 dunes, bleached white, show complex diagenesis with calcite, kaolinite, and böhmite, likely influenced by hydrothermal fluids rich in CO₂, H₂S, or H₂ from underlying igneous intrusions, resulting in lower porosity and permeability. Type 3 diagenesis reflects rapid induration due to lava contact ('volcano-eogenesis'), limited to shallow depths near lava interfaces. The study highlights volcanic-driven compartmentalization in sediment-lava sequences, offering insights into natural CO₂ sequestration processes and implications for hydrocarbon exploration.

Grove, C., Jerram, D. A., Gluyas, J. G., & Brown, R. J. (2017). Sandstone Diagenesis in Sediment–lava Sequences: Exceptional Examples of Volcanically Driven Diagenetic Compartmentalization in Dune Valley, Huab Outliers, Nw Namibia. Journal of Sedimentary Research, 87(12), 1314–1335. https://doi.org/10.2110/jsr.2017.75