Magmatic evolution of compositionally heterogeneous monogenetic Cenozoic Strzelin Volcanic Field (Fore-Sudetic Block, SW Poland)

Abstract

Erosional remnants of the Miocene Strzelin Volcanic Field in SW Poland were studied in terms of volcanology, petrology and Sr-Nd-Pb isotope geochemistry with the aim to identify the reasons for compositional variability of monogenetic volcanoes. The obtained data suggest that a heterogeneous mantle peridotite (with mixed DM/HIMU signature) was the dominant source of magmas. Partial melting and segregation of magmas in diapirically rising asthenosphere occurred within the garnet stability field. The source heterogeneity was the basic cause that controlled the compositional variability of the primary magmas, and also influenced the subsequent differentiation processes and eruptive styles. On the surface, additional role was played by variable environments (i.e. phreatomagmatic eruptions in water-saturated environments). More fertile mantle domains, with prevailing HIMU component, released melts deeper, at lower degrees of partial melting and small magma batches were formed. These nephelinitic magmas underwent only limited fractional crystallization en route to the surface and erupted with low explosivity as lava flows. In contrast, less fertile mantle domains, dominated by the DM component, released melts at higher degrees of partial melting at a shallower depth. This resulted in a more sustained magma supply that further enhanced the development of shallow-level magmatic systems, with more advanced and complex differentiation: larger degrees of fractional crystallization as well as replenishment by new batches of primitive magma. The resulting basaltic and trachybasaltic volcanoes showed a greater diversity of eruptive styles, including effusive and variably explosive eruptions.

A Geophysical Model for the Origin of Volcano Vent Clusters in a Colorado Plateau Volcanic Field

“…The origin of vent clusters within distributed volcanic fields remains uncertain. One model is that magma source regions are heterogenous (e.g., Awdankiewicz et al, ), with some areas of the mantle more prone to partial melting than others leading to more frequent and voluminous activity in some parts of the field compared to others, a mechanism previously invoked to explain vent clusters in the SVF (Condit & Connor, ). Alternatively, the crust may act as a filter.…”

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

“…Most of the magmatism was concentrated along the Eger Rift, which represents the eastern most branch of the European Cenozoic Rift System (Figure ; e.g., Dèzes et al, ; Rajchl et al, ). Apart from the main volcanic complexes (see, e.g., Rapprich & Holub, ; Cajz et al, ; Skála et al, ; Ackerman et al, ), several volcanic fields were also formed on the shoulders of the rift (Awdankiewicz, ; Awdankiewicz et al, ; Büchner & Tietz, ; Büchner et al, ; Haase et al, ; Petronis et al, ; Rapprich et al, ; Tietz & Büchner, ; Valenta, Rapprich, Skácelová, Gaždová, & Fojtíková, ; Wenger et al, ). Our study focused on the Zebín Volcano, located in the Jičín Volcanic Field (Rapprich et al, ; Figure ) in the southeast of the Eger Rift, where Miocene volcanic rocks were emplaced into, or erupted onto, Upper Cretaceous marine sediments of the Bohemian Cretaceous Basin and continental Permo‐Carboniferous strata of the Krkonoše Piedmont Basin.…”

Petrology of weakly differentiated alkaline, high-level intrusive rocks in the Zahořany-Chotiněves Belt near Litoměřice (Czech Republic)

“…Two main volcanic complexes -České Středohoří and Doupovské hory volcanic complexes -have emerged within the Ohře Rift (e.g., Cajz et al 1999Cajz et al , 2009Ulrych et al 2002;Rapprich and Holub 2008;Holub et al 2010;Skála et al 2014;Ackerman et al 2015). The formation of these major volcanic complexes was paralleled by scattered monogenetic volcanism in several volcanic fields on both rift-shoulders (e.g., Awdankiewicz 2005;Rapprich et al 2007;Büchner and Tietz 2012;Valenta et al 2014;Petronis et al 2015;Tietz and Büchner 2015;Awdankiewicz et al 2016;Haase et al 2017;Wenger et al 2017).…”