Supra-subduction zone ophiolites of Central Anatolia: geochemical evidence from the Sarikaraman Ophiolite, Aksaray, Turkey

Abstract

The Central Anatolian Crystalline Complex (CACC), situated between the northern and southern oceanic strands of Neotethys, contain a number of little-studied ophiolitic bodies of late Cretaceous age that have a bearing on the Mesozoic development of this region. The pillow lavas and sheeted dykes of the Safikaraman Ophiolite were originally a comagmatic differentiated series of vesicular, aphyric and olivine-poor, plagioclase-clinopyroxene phyric tholeiites, but now exhibit gmenschist facies assemblages. A set of late dolerite dykes cross-cutting the whole volcanic sequence are more chemically evolved and were probably derived from a different source. Relative to N-MORB the lavas and dykes are enriched in some LIL elements (K, Rb, Cs, U, Th and St) and depleted in HFS elements (Nb, Ta, Hf, Zr, Ti and Y) and light REE. In terms of immobile elements the ophiolitic basalts have the broad chemical characteristics of island arc tholeiites that were formed in a supra-subduction zone setting, whereas the late dykes are more akin to N-MORB. In this respect the Sarikaraman Ophiolite is similar to other ophiolites found in the eastern Mediterranean region and emphasizes the preservation of this particular environment in the CACC. If all the Central Anatolian Ophiolites (of which the Sarikaraman Ophiolite is one example) were derived via southward thrusting from the Vardar-Izmir-Ankara-Erzincan Ocean branch to the north, age relationships suggest that this segment of ocean crust was relatively short-lived before obduction onto the CACC.

Source of the mineralizing fluids in ultramafic related magnesite in the Eskişehir area, northwest Turkey, along the İzmir–Ankara Suture: a stable isotope study

“…Göncüoğlu et al (2006) indicated that radiolarian evidence suggests that rifting of the Neotethys İzmir-Ankara Zone occurred in the Late Triassic and the İzmir-Ankara oceanic plate did not get subducted until the Cenomanian. Defining the formation of the supra-subduction zone (SSZ) type oceanic crust in the eastern part of the İzmir-Ankara Suture Belt, Göncüoğlu and Türeli (1993) and Yalınız et al (1996) accepted that the İzmir-Ankara oceanic basin began to close by intraoceanic subduction (Göncüoğlu and Türeli, 1993;Tüysüz et al, 1995;Göncüoğlu et al, 1997Göncüoğlu et al, , 2006Okay and Tüysuz, 1999). The oldest ages obtained from the amphibolites in the İzmir-Ankara Suture Zone were between 101 Ma (Harris et al, 1994;Göncüoğlu et al, 2006) and 90 Ma (Önen, 2003;Göncüoğlu et al, 2006).…”

Study of Serpentinized Ultramafic Rocks of Bela Ophiolite, Balochistan, Pakistan

“…The lower unit comprises of tectonic accretionary wedge of older back-arc basin lithologies, including high-Ti mafic rocks. Yaliniz et al (1996) have divided the ophiolites of the region into two groups; western MOR Jurassic and eastern suprasubduction (SSZ) Cretaceous ophiolites. The SSZ features often comparable with younger back-arc basins worldwide (Pearce et al, 1994).…”

Travertine occurrences along major strike-slip fault zones: structural, depositional and geochemical constraints from the Eastern Anatolian Fault System (EAFS), Turkey

“…On the otherhand, ophiolitic masses are emplaced on the continental crust (Beyarslan & Bingöl, 2000;Parlak, Höck, Kozlu, & Delaloye, 2004;Parlak & Robertson, 2004;Robertson, 2002Robertson, , 2004Yalınız, Floyd, & Göncüoğlu, 1996. Tertiary units deposited in back-arc basins are most common (Aksoy, Türkmen, & Turan, 2005;Aktaş & Robertson, 1984;Cronin et al, 2000;Özkul & Kerey, 1996;Yazgan, 1984).…”