Geological Units and Structures in Suture Zone Around Balıkesir NW Anatolia

Authors: H. Serdar AKYÜZ

Abstract: The region norheast of Balıkesir comprises different group of rocks reflecting different tectonic settings. Sakarya zone and Tavşanlı Zone are separated by a Mesozoic Tethyan suture zone called İzmir-Ankara suture. Sakarya zone, represented by Karakaya Complex in the study area, is located to the north of a major fault, which marks the northern boundary of Neo-Tethyan suture zone. The Karakaya complex reflects active continental margin units that were formed by southward subduction of Paleo-Tethyan oceanic crust during Permo- Triassic. At this perod, Karakaya complex units were internally imbricated. The closure of the Neo-Tethys ocean, leading HP/LT metamorphizm of northward subducting platform sediments (Orhaneli unit), resulted in the formation of two distinct tectonic units during late Mesozoic to Paleocene; an ophiolotic melange (Ovacık melange) and fault controlled wild-flysch (Bornova flysch). Ovacık melange, which was originally tectonically underlein by Orhaneli unit, detached during uplift of blueschist. Bornova flysch has back-thrushed over Sakarya zone during late Paleocene-?Eocene. A large garnitic pluton, Çatldağ granodiorite, which is a pruduct of extensive calc-alkaline magmatism in NW Anatolia, emplaced into the older units during Early Miocene, and caused titing of older structures around pluton.

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