Skip to content

The explosive eruption of carbonatite and associated pyroclast textures

Chiedozie C. Ogbuagu 1,2,3, Thomas J. Jones4, Benjamin F. Walter5, Sebastian Staude6, Michael Marks6, Silvio de Angelis1, Kuang C. Lin2

  • Affiliations: 1School of Environmental Sciences, University of Liverpool, Liverpool L69 3GP, UK; 2Department of Engineering and System Science, National Tsing Hua University, Hsinchu 30013, Taiwan; 3Department of Geology, University of Nigeria, Nsukka 410001, Enugu State, Nigeria; 4Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK; 5Petrology and Mineral Resources, University of Tübingen, Schnarrenbergstraße 94-96, 72074, Tübingen, Germany; 6Department of Geosciences, University of Tübingen, Schnarrenbergstrasse 94-96, D-72076, Tübingen, Germany

  • Presentation type: Talk

  • Presentation time: Monday 15:45 - 16:00, Room S150

  • Programme No: 3.6.5

  • Theme 3 > Session 6

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. Carbonatites are another magma composition, that are also characterised by low melt viscosities. However, their eruptions are much less frequent, and observations of explosive carbonatite eruptions are minimal. Here, we examined the textural features of carbonatite pyroclasts from the Miocene Kaiserstuhl Volcanic Complex, which hosts both intrusive and extrusive suites of carbonatite rocks. Three pyroclastic rock samples from the Kirchberg and Hechtsberg regions of the complex were studied using optical petrography, scanning electron microscopy, and image analysis techniques. Our observations show that the pyroclasts, after primary fragmentation, aerodynamically deformed in flight and experienced pyroclast-pyroclast collisions to form complex, agglutinated pyroclasts. Further image analysis has enabled us to reconstruct the primary grain size distribution, representing primary pyroclast formation and their textural features before agglutination. Finally, these data are used to inform on the fragmentation processes and intensities of explosive carbonatites eruptions. Keyword: carbonatite, in-flight deformation, agglutination, textural features, grain size distribution