Ogbuagu, Chiedozie and Jones, Thomas and De Angelis, Silvio and Walter, Benjamin and Marks, Michael (2025) Pyroclast textures generated during the explosive eruption of carbonatite. Journal of Volcanology and Geothermal Research: 108526. ISSN 0377-0273 (In Press)
Full text not available from this repository.Abstract
Explosive eruptions of low viscosity lava, such as basalts and basanites, are widespread and are a dominant form of volcanism on Earth. They commonly display Hawaiian and Strombolian eruption styles and are relatively well documented. Carbonatite, another magma composition distinguished by a high volume fraction of carbonate minerals, is also characterised by low melt viscosities. However, documented examples of explosive carbonatite eruptions are very rare. We examined the composition and textural features of carbonatite pyroclasts from the Miocene Kaiserstuhl Volcanic Complex, Germany. Three pyroclastic rock samples from the Kirchberg and Henkenberg regions of the complex were studied using optical petrography, scanning electron microscopy, and image analysis techniques. Our observations indicate that after primary fragmentation, the pyroclasts underwent in-flight relaxation and experienced pyroclast-pyroclast collisions to form complex, agglutinated pyroclasts. The vesicles within the pyroclasts are well preserved by secondary mineralisation of carbonates. Comprehensive image analysis enabled the reconstruction of both the primary and secondary (agglutinated) grain size and shape distributions, which represent the initial, primary formation of pyroclasts and their textural features after agglutination. Finally, these data are used interpret the potential fragmentation processes and eruption conditions for the extrusive carbonatites of the Kaiserstuhl volcanic complex.