Gökçeada Island, which is situated west of Biga Peninsula, has widespread magmatism with variable ages. Lower-Middle Eocene Dağiçitepe volcanics are the oldest volcanic unit in the island and consist of lavas, tuff-tuffites. They are influenced by alteration and almost all minerals, except quartz, are transformed into other minerals. Lower Oligocene Gökçeada andesitic lava/ domes exhibiting hypocrystalline porphyric texture, are the products of NE-SW trending domes/ cryptodomes. The phenocrysts assemblages consist of plagioclase, hornblende, clinopyroxene ± biotite and quartz. Middle Miocene Eşelek volcanics, which occur as lavas and pyroclastic rocks, exhibit hypocrystalline porphyric and intersertal textures. They are composed of plagioclase, hornblende and clinopyroxene crystals. Rhyolitic Dağiçitepe volcanics and andesitic Gökçeada lava/domes have calc-alkaline, andesitic Eşelek volcanics have tholeiitic character. They have geochemical features similar to subduction-related magmas. Lower-Middle Eocene Dağiçitepe volcanics are the products of syn-collisional magmas that have undergone processes of crustal contamination due to thickened crust. Whereas, Lower Oligocene Gökçeada andesitic lava/domes are the products of post-collisional magmas and were derived from metasomatized lithospheric mantle. Middle Miocene Eşelek volcanics were also derived from lithospheric mantle but, the mantle source generating Eşelek volcanics were relatively depleted over time. Geochemical data demonstrate the decreasing role of subduction signature and crustal contamination during the genesis and evolutionof Gökçeada volcanics from Lower-Middle Eocene to Middle Miocene.
Gökçeada Volcanism Crustal contamination Petrogenetic modeling Partial melting
This study has been carried out within the Project of “Batı Anadolu Polimetal Maden Aramaları (Western Anatolia Polymetallic Mineral Explorations)” in the Mineral Research and Exploration Department of General Directorate of Mineral Research and Exploration (MTA). We would like to thank to the Department of the Mineral Research and Exploration and the Northwest Anatolian Regional Directorate for their contributions during the study. We are grateful to Prof. Dr. Namık Aysal, Prof. Dr. Erdinç Yiğitbaş and the anonymous referee for their valuable and constructive reviews that greatly improved the manuscript.
Birincil Dil | İngilizce |
---|---|
Konular | Mühendislik |
Bölüm | Makaleler |
Yazarlar | |
Yayımlanma Tarihi | 15 Nisan 2020 |
Yayımlandığı Sayı | Yıl 2020 Cilt: 161 Sayı: 161 |
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