Akademik Veri Yönetim Sistemi
12h International Multidisciplinary Scientific Geoconference (SGEM), Albena, Bulgaristan, 17 - 23 Haziran 2012, ss.391-398, (Tam Metin Bildiri)
Neogene magmatic activity is widespread in western Anatolia and the Aegean region. Susurluk magmatic domain that is part of the Neogene magmatic belt of western Anatolia comprises various products of Miocene magmatism including plutonic and volcanic associations. These volcanic and plutonic rocks, namely Cataldag pluton and Susurluk volcanites, are spatially and temporally associated with each other. Susurluk Volcanites have two main volcanostratigraphic groups; felsic volcanic rocks (dacitic lavas and related pyroclastic rocks) and intermediate volcanic rocks (andesitic-trachyandesitic lavas and associated pyroclastic rocks). The relationships between these volcano-stratigraphic groups and their areal distributions in the study area indicate that the Susurluk volcanites were produced by sub-plinian eruptions of small vents surrounding the Cataldag pluton. Geochemical characteristics of Susurluk volcanites indicate that they are formed from dacites, andesites and trachyandesites. This result is consistent with our field and petrographic investigations. Dacite lavas are high-K calc-alkaline in character, whereas andesites (and trachyandesites) are medium-to high-K calc-alkaline in composition. Both group show enrichment in large ion lithophile elements (LILE) and light rare earth elements (LREE) relative to the high field strength elements (HFSE). They have high initial Sr-87/Sr-86 ratios (0.707099-0.708785) and low Nd-143/Nd-144 (0.512407-0.512575). Pb-206/Pb-204 and Pb-207/Pb-204 values vary from 18,831 to 18,952 and 15,696 to 15,704, respectively and epsilon Nd values range between -4.0 and -0.72. These similar isotopic characteristics indicate that felsic and intermediate groups belonging to Susurluk Volcanites are co-genetic and they were originated from a common magma derived from enriched mantle (EM II type). Our new major-trace element and Sr-Nd-Pb isotope data also suggest that both mantle enrichment and crustal contamination (combined with fractional crystallization) are required to explain the magmatic evolution of Susurluk volcanites.