Erratum to: Review of post-collisional volcanism in the Central Anatolian Volcanic Province (Turkey), with special reference to the Tepekoy Volcanic Complex |
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| Authors: | Gonca Gencalioglu Kuscu Fatma Geneli |
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| Institution: | (1) Department of Geological Engineering, Mugla University, 48000 Mugla, Turkey;(2) Department of Geological Engineering, Middle East Technical University, 06532 Ankara, Turkey |
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| Abstract: | Neogene-Quaternary post-collisional volcanism in Central Anatolian Volcanic Province (CAVP) is mainly characterized by calc-alkaline
andesites-dacites, with subordinate tholeiitic-transitional-mildly alkaline basaltic volcanism of the monogenetic cones. Tepekoy
Volcanic Complex (TVC) in Nigde area consists of base surge deposits, and medium to high-K andesitic-dacitic lava flows and
basaltic andesitic flows associated with monogenetic cones. Tepekoy lava flows petrographically exhibit disequilibrium textures
indicative of magma mixing/mingling and a geochemisty characterized by high LILE and low HFSE abundances, negative Nb–Ta,
Ba, P and Ti anomalies in mantle-normalized patterns. In this respect, they are similar to the other calc-alkaline volcanics
of the CAVP. However, TVC lava flows have higher and variable Ba/Ta, Ba/Nb, Nb/Zr, Ba/TiO2 ratios, indicating a heterogeneous, variably fluid-rich source. All the geochemical features of the TVC are comparable to
orogenic andesites elsewhere and point to a sub-continental lithospheric mantle source enriched in incompatible elements due
to previous subduction processes. Basaltic monogenetic volcanoes of CAVP display similar patterns, and HFS anomalies on mantle-normalized
diagrams, and have incompatible element ratios intermediate between orogenic andesites and within-plate basalts (e.g. OIB).
Accordingly, the calc-alkaline and transitional-mildly alkaline basaltic magmas may have a common source region. Variable
degrees of partial melting of a heterogeneous source, enriched in incompatible elements due to previous subduction processes
followed by fractionation, crustal contamination, and magma mixing in shallow magma chambers produced the calc-alkaline volcanism
in the CAVP. Magma generation in the TVC, and CAVP in general is via decompression melting facilitated by a transtensional
tectonic regime. Acceleration of the extensional regime, and transcurrent fault systems extending deep into the lithosphere
favoured asthenospheric upwelling at the base of the lithosphere, and as a consequence, an increase in temperature. This created
fluid-present melting of a fluid-enriched upper lithospheric mantle or lower crustal source, but also mixing with asthenosphere-derived
melts. These magmas with hybrid source characteristics produced the tholeiitic-transitional-mildly alkaline basalts depending
on the residence times within the crust. Hybrid magmas transported to the surface rapidly, favored by extensional post-collision
regime, and produced mildly alkaline monogenetic volcanoes. Hybrid magmas interacted with the calc-alkaline magma chambers
during the ascent to the surface suffered slight fractionation and crustal contamination due to relatively longer residence
time compared to rapidly rising magmas. In this way they produced the mildly alkaline, transitional, and tholeiitic basaltic
magmas. This model can explain the coexistence of a complete spectrum of q-normative, ol-hy-normative, and ne-normative monogenetic
basalts with both subduction and within-plate signatures in the CAVP. |
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