Interplay between volcanic and plutonic systems: A case study of the early Miocene Solarya Volcano-plutonic Complex in NW Anatolia (Turkey)

Abstract

Linking volcanic and plutonic systems and examining them, together is critical to evaluate magma chamber processes and mantle-crust, interactions in lithospheric scale. Solarya Volcano-plutonic complex, (SVPC) is one of the major volcano-plutonic complexes located in NW, Turkey and it is remarkable for its coeval and cogenetic plutonic, hypabyssal and volcanic rocks. Solarya pluton (22 Ma) is an epizonal, pluton which consists of three main rock groups; K-feldspar, megacrystalline granodiorite, microgranodiorite and haplogranite. Plutonic rocks pass into hypabyssal association, represented by, granodiorite/quartz-diorite porphyry sheet intrusive rocks which were, injected into the ring and radial faults concurrently with the, emplacement of the pluton. Hypabyssal and volcanic rocks cut one another, and fragments of hypabyssal rocks are found in volcanic rocks. Volcanic, association, is formed from trachyandesite, andesite and dacite lavas, with associated pyroclastic rocks. New 40Ar/39Ar radiometric ages of, volcanic and hypabyssal associations display that, they have 40Ar/39Ar, biotite ages changing from 23.1 ± 0.2 to 21.0 ± 0.2 indicating that they, are coeval with Solarya Plutonic Association. Petrographical features of, SVPC display disequilibrium textures such as oscillatory zoning, sieve, and honeycomb textures in plagioclase, reverse mantled biotite and, hornblende crystals as indicatives of open system magma chamber processes, (mixing/mingling and/or AFC). Plutonic, hypabyssal and volcanic, associations of SVPC show similar major-trace and Sr-Nd-Pb-O isotopic, compositions indicating a common magma source and similar magma chamber, processes. They are medium to high-K calc-alkaline rocks and display, enrichment in LILE and depletion in Nb, Ta, P and Ti. The geochemical and, isotopic characteristics of SVPC are considered to reflect an enriched, mantle (EMII) or sub-continental lithospheric mantle source. Bulk mixing, model between ƐNd and 87Sr/86Sr isotopic data suggests that, the crustal, contribution to the enriched mantle source is about 25–45%. Evaluation of all these data suggests that, Solarya Volcano-plutonic, Complex with early Miocene age was developed under syn-convergent, extensional regime concurrent with the exhumation of other major volcanoplutonic, and core complexes (eg. Kozak, Menderes, Kazdağ, Çataldağ) in NW, Anatolia.