LATE CRETACEOUS ARC MAGMATISM IN THE SOUTHERN CENTRAL PONTIDES: CONSTRAINTS FOR THE CLOSURE OF THE NORTHERN NEOTETHYAN BRANCHES


SAYIT K. , Cemal Göncüoğlu M., Ellero A., Ottria G., Frassi C., Marroni M., ...More

Ofioliti, vol.47, no.1, pp.19-35, 2022 (Journal Indexed in SCI Expanded) identifier

  • Publication Type: Article / Article
  • Volume: 47 Issue: 1
  • Publication Date: 2022
  • Doi Number: 10.4454/ofioliti.v47i1.549
  • Title of Journal : Ofioliti
  • Page Numbers: pp.19-35
  • Keywords: Andesites, Central pontides, Geodynamics, Neotethys ocean, Northern Turkey, Volcanic arc

Abstract

© 2022, Edizioni ETS. All rights reserved.In the southern Central Pontides in northern Turkey the remnants of two Neotethyan oceanic basins, currently represented by the Intra-Pontide and the Izmir-Ankara-Erzincan sutures, and the interposing continental microplate (i.e., the Sakarya Composite Terrane) are completely dissected by the North Anatolian Shear Zone (NASZ). Within the resulting kilometre-scale, strike-slip fault-bounded blocks, several Late Cretaceous arc-type magmatic units have been detected. In this paper, we present new geochemical data from one of these magmatic units, the Yerkuyu Unit, that forms an ENE-WSW trending 30-km long and 10-km wide lens-shaped body surrounded by the splays of the NASZ. The studied igneous lithologies have a subduction-related magmatic geochemical signature matching with another lozenge-shaped magmatic block of the Tafano Unit. However, the tectono-magmatic characterization indicates that the Tafano Unit magmatism developed within a continental arc tectonic setting, while the volcanic rocks of the Yerkuyu Unit derived from oceanic arc magmatism. This finding indicates that the subducted oceanic lithosphere of the İzmir-Ankara-Erzincan branch of the Neotethys Ocean produced oceanic volcanic arcs close to the subduction zone (i.e., the Yerkuyu Unit) and beneath the Sakarya continental microplate (i.e., the Tafano Unit).