Ophiolites and Ophiolitic Mélanges of Turkey: A Review

Yıl 2013, Cilt: 56 Sayı: 2, 61 - 114, 01.04.2013

Ali Yılmaz Hüseyin Yılmaz

Öz

The aim of the presented study is to review the ophiolites and ophiolitic mélanges of Turkey  and their importance for constraints on the evolution of the region. On the basis of the existing data, the ophiolitic associations of Turkey are classified into three main groups.

1. Group comprises pre-Alpine ophiolites and mélanges located on the southern edge of the Istanbul zone. These associations are in Pre-Jurassic age, and represent ophiolitic sequences of the Pontide Suture zone. The Karakaya complex represents pre-Alpine ophiolitic mélange and developed during the emplacement of the pre-Alpine ophiolites. The opening and closing ages and polarity of the Paleotethys is still a question.

2. Group can be divided into two sub-belts and they are the Northern-Northeastern and the Southern sub belt. They are allied to the North Anatolian Ophiolitic Belt (NAOB). The northern-northeastern subbelt extends from Izmir to eastward, continuing as the Ankara-Erzincan zone and as the Sevan-Akera sub-belt of the Lesser Caucasus Ophiolitic Belt (LCOB). This sub-belt directly represents the northern branch of Neotethys. The ophiolites of this sub-belt represent dismembered ophiolitic sequences and take place within the Late Cretaceous melanges. The southern sub-belt begins in the Marmaris area and continues eastward to the Hadim, Aladağlar, Tecer-Divriği, Erzurum, Kağızman areas, and then on to the Vedi sub-belt of the LCOB. The ophiolitic outcrops of the Hınıs area and northeast of Lake Van, may be the southernmost products of the southern sub-belt of the NAOB associations. In the framework of age, composition, and tectonic setting ophiolites and mélanges of the southern sub-belt and northern sub belt show similar characteristic features. Therefore the southern subbelt units may be tectonically transported products of the northern sub-belt. The opening of the northern branch of Neotethys began in Triassic time in the west, in the Jurassic in the east. The closing of the northern branch of Neotethys was initiated in the Late Cretaceous and ended in pre-Middle Eocene time. 

3. Group is represented by the Southern and Southeastern Anatolian Ophiolitic Belt (SAOB) comprising Jurassic-Lower Cretaceous ordered ophiolitic sequences and Late Cretaceous mélanges. Opening of the southern Neotethys began in Triassic and closure began in the Late Cretaceous and ended in pre-Late Miocene. 

2. and 3 groups of ophiolites with mélanges are separated from one another by the Taurus Unmetamorphic Axis of the Anatolide-Tauride block These ophiolites together include Mid Ocean Ridge Basalt (MORB) and Supra-subduction zone (SSZ) type ophiolites, emplaced along double northward subduction zones in Late Cretaceous. The emplacement style for the ophiolitic units along NAOB and SAOB show a flower structure, on the basis of the presence of north- and south-facing overthrusts. 

Anahtar Kelimeler

Alpine ophiolites, mélanges, pre- Alpine ophiolites, sutures

Kaynakça

• Adamia, Sh., Abesadze, M., Kekelia, M., Chkhotua, T. and Shavishvili I., 1978. Metamorphic ophiolites, island-arc
• complexes and blastomylonites of the Great Caucasian Main Range (in Russian). Doklady Acad. Sci. USSR, 241
• See PDF file for more references