GEOCHEMISTRY AND PETROGENESIS OF THE ARC-RELATED KÖSDAĞ METAVOLCANICS, SOUTHERN CENTRAL PONTIDES, NORTHERN TURKEY

2021-12-27
Berber, Faruk
The Kösdağ Metavolcanics (KM) in the southern Central Pontides crops out between the Izmir-Ankara-Erzincan Suture Zone (IAESZ) in the south and the Sakarya Composite Terrane in the north. The unit is represented by a low-grade metamorphic assemblage including meta-basics, meta-intermediates, and meta-felsics, interlayered with recrystallized limestone, mudstone, and chert. While the unit is bounded to the north by the North Anatolian Fault Zone (NAFZ), the Dikmen Formation stratigraphically overlie the unit in the south. Geochemically, the KM are sub-alkaline and divided into two main groups as Type 1 and Type 2, based on their relative Zr-Hf enrichment/depletion. The high Zr/Nb (3.3-85.8), low Zr/Y (0.6-6.9), and Nb/Y (0.02-0.19) ratios suggest that the KM have been derived from a depleted mantle source resembling that of N-MORBs. Positive εNd values shown by the KM, ranging from + 2.9 to + 6.5, support the dominant involvement of depleted mantle source with a minor contribution from recycled and/or subduction components. Enrichment in Th and La compared to Nb (and Ta) indicates subduction-related magmatism fort he KM. The melting models imply derivation of the KM from a spinel lherzolitic source. LA-ICP-MS U-Pb vi zircon ages of the KM range from 96.9 ± 1.3 Ma to 93.7 ± 1.2 Ma. Combined geological and geochemical evidence indicates an oceanic arc origin for the KM. The geodynamic model proposed in this study involves the presence of an intra-oceanic subduction zone during the early Late Cretaceous within the IAE branch of the Neotethys Ocean in the Central Pontides.

Suggestions

Geochemistry and U-Pb ages from the Kosdag Metavolcanics in the southern Central Pontides (Turkey): Complementary data for early Late Cretaceous island arc development in the Northern Neotethys
BERBER, Faruk; Sayıt, Kaan; Göncüoğlu, Mehmet Cemal (2021-01-01)
The Kosdag Metavolcanics (KMs) in the southern Central Pontides are exposed between the Izmir-Ankara-Erzincan Suture Belt in the south and the Sakarya Composite Terrane in the north. They comprise an approximately 40-km-long tectonic unit, bounded by the splays of the North Anatolian Transform Fault in the north and the Kizilca Thrust in the south. The basement of the unit mainly consists of metabasalts, metaandesites, and metarhyolites, with well-developed blastomylonitic textures, which are interlayered b...
GEOLOGICAL AND GEOCHEMICAL EVIDENCE FOR A LATE CRETACEOUS CONTINENTAL ARC IN THE CENTRAL PONTIDES, NORTHERN TURKEY
Ellero, Alessandro; Ottria, Giuseppe; Sayıt, Kaan; Catanzariti, Rita; Frassi, Chiara; Göncüoğlu, Mehmet Cemal; Marroni, Michele; Pandolfi, Luca (2015-01-01)
In the Central Pontides (Northern Turkey), south of Tosya, a tectonic unit consisting of not-metamorphic volcanic rocks and overlying sedimentary succession is exposed inside a fault-bounded elongated block. It is restrained within a wide shear zone, where the Intra-Pontide suture zone, the Sakarya terrane and the Izmir-Ankara-Erzincan suture zone are juxtaposed as result of strike-slip activity of the North Anatolian shear zone. The volcanic rocks are mainly basalts and basaltic andesites (with their pyroc...
Geological, mineralogical and geochemical characteristics of Mississippian K-bentonites from southern Turkey: A correlation with coeval tephras from Gondwana-derived terranes
Bozkaya, Ömer; Günal Türkmenoğlu, Asuman; Göncüoğlu, Mehmet Cemal; Okuyucu, Cengiz (2021-09-01)
Five thin (5–15 cm) and yellowish green tephra (K-bentonite) layers are exposed along two sections in the south of Akşehir (Konya, southern Turkey) within the Early Carboniferous (Mississippian) red dolomite-dolomitic limestone succession of the Sultandağ Unit in the central Tauride Belt. K-bentonites exhibit typical porphyritic texture with euhedral plagioclase phenocrysts replaced by fine-grained white K-micas and sparry dolomite crystals. The intensively sericitized volcanic matrix has vitrophyric textur...
Geochemistry, tectono-magmatic discrimination and radiolarian ages of basic extrusives within the Izmir-Ankara Suture Belt (NW Turkey): Time constraints for the neotethyan evolution
Göncüoğlu, Mehmet Cemal; Tekin, U. Kagan (2006-06-01)
The Dagkuplu Melange in the Central Sakarya Valley represents the northernmost outcrops of the Izmir-Ankara Suture Belt in northwest Anatolia. In addition to blocks and slivers of serpentinite, gabbro, blueschist, neritic and pelagic limestones, it includes blocks of basic volcanic rocks associated with radiolarian cherts, pelagic carbonates and mudstones.
Metamorphic imprint of ridge subduction on the Neo-Tethyan ophiolites from the Saka Unit (Central Pontides, northern Turkey)
Frassi, Chiara; Rebay, Gisella; Marroni, Michele; Sayıt, Kaan; Göncüoğlu, Mehmet Cemal; Ellero, Alessandro; Ottria, Giuseppe; Pandolfi, Luca (2020-09-01)
The Intra-Pontide suture zone is the northernmost ophiolite suture zone exposed in the Anatolian peninsula. It consists of several variably deformed and metamorphosed tectonic units derived from the Neo-Tethyan IntraPontide oceanic (IPO) basin, and its continental margins that are currently represented by the Istanbul Zonguldak and the Sakarya terranes. Recent data suggests that the IPO was a wide supra-subduction oceanic basin whose closure began in the uppermost Early Jurassic by a north dipping intra-oce...
Citation Formats
F. Berber, “GEOCHEMISTRY AND PETROGENESIS OF THE ARC-RELATED KÖSDAĞ METAVOLCANICS, SOUTHERN CENTRAL PONTIDES, NORTHERN TURKEY,” Ph.D. - Doctoral Program, Middle East Technical University, 2021.