Emplacement History of the Miocene Zebín Tuff Cone (Czech Republic) Revealed From Ground Geophysics, Anisotropy of Magnetic Susceptibility, Paleomagnetic, and ⁴⁰Ar/³⁹Ar Geochronology Data

Abstract

The Zebín Volcano, Czech Republic, is a quarried tuff cone that offers the opportunity to understand emplacement processes responsible for magma transport through a pyroclastic cone and magmatic processes involved in its development. A high‐resolution ground magnetometry survey, electrical resistivity tomography, and refraction seismic were conducted to supplement field mapping of the size, shape, and inner structure of the volcanic system. The Zebín Volcano yields normal polarity rocks, and the cone is underlain by a complex and branching magma feeder system with several diverging dikes. Samples were collected at 24 sites from feeder dikes and the main conduit for anisotropy of magnetic susceptibility and paleomagnetic analysis. Anisotropy of magnetic susceptibility results yield inferred magma flow directions indicating subhorizontal magma flow toward and away from the axial conduit as well as both upward and downward flow. Paleomagnetic data from all sites are normal polarity with statistically distinct remanence directions between some sites that indicate that significant time passed or deformation occurred during the growth of this volcanic system. 40Ar/39Ar isochron ages of groundmass provide emplacement ages of 18.38 ± 0.03 and 18.45 ± 0.03 Ma, whereas a weighted mean date of 18.52 ± 0.03 Ma for hornblende provides an eruption age. We argue that the Zebín Volcano evolved from a polyphase feeding system and through a complex feeder network. This detailed study shows that many monogenetic volcanoes deserve highly detailed study, as their subtleties can provide insight into broader crustal and magmatic environment during magmatism.

The Way to the Rocks—Changes of Networks of Hiking Trails in Chosen Sandstone Landscapes in Poland and the Czech Republic in the Period of Political Transformation

“…Stratigraphy includes rock series from the Cenomanian to the Coniacian (Migoń and Pijet-Migoń 2006;Uličný 2001;Uličný et al 2009). The relief was also influenced by Neogene volcanism, which is reflected today in locally present necks and lava covers (Petronis et al 2015(Petronis et al , 2018Rapprich et al 2007Rapprich et al , 2017b. Currently, the entire Bohemian Paradise has been recognised not only as a protected landscape area (what happened already in 1955), but also-in 2005 as the first such area in the Czech Republic-as a geopark, being now a member of national, European and global geopark networks (Kubalíková 2018;Migoń and Pijet-Migoń 2006).…”

Two Small Volcanoes, One Inside the Other: Geophysical and Drilling Investigation of Bažina Maar in Western Eger Rift

“…This is especially the case when the tuff ring surrounding the crater is eroded and/or the maar crater is completely filled with post‐eruptive sediments of any type. While the internal structure of other monogenetic volcanoes can be revealed by erosion or quarrying (e.g., Foucher et al., 2018; Hintz & Valentine, 2012; Keating et al., 2008; Petronis et al., 2013, 2018), the rock sequences of the maar infill can be more blurred due to their less coherent and more erodible nature compared to country rocks. In the case of older (pre‐Pliocene) maar‐diatreme volcanoes, the subsequent erosion of the surrounding country rocks may expose the diatreme facies, but usually without maar‐filling sequences (e.g., Latutrie & Ross, 2019, 2021; Lefebvre et al., 2013; Skácelová et al., 2010; Valenta et al., 2014).…”