LATE CRETACEOUS ARC AND BACK-ARC FORMATION WITHIN THE SOUTHERN NEOTETHYS: WHOLE-ROCK, TRACE ELEMENT AND Sr-Nd-Pb ISOTOPIC DATA FROM BASALTIC ROCKS OF THE YUKSEKOVA COMPLEX (MALATYA- ELAZIG, SE TURKEY)


Ural M., ARSLAN M. , GÖNCÜOĞLU M. C. , TEKİN U. K. , Kurum S.

OFIOLITI, vol.40, no.1, pp.57-72, 2015 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 40 Issue: 1
  • Publication Date: 2015
  • Doi Number: 10.4454/ofioliti.v40i1.435
  • Title of Journal : OFIOLITI
  • Page Numbers: pp.57-72
  • Keywords: melange basalts, petrology, arc-back arc, Southern Neotethys, ULTRABASIC VOLCANIC-ROCKS, LOG-TRANSFORMED RATIOS, HIGH-FIELD STRENGTH, ISLAND-ARC, TECTONIC DISCRIMINATION, HYDROTHERMAL ALTERATION, EASTERN TAURIDES, OCEANIC BASALTS, OPHIOLITE, EVOLUTION

Abstract

The remnants of the Southern Neotethys are represented by ophiolitic bodies and subduction/accretion complexes along the Southeast Anatolian-Zagros suture belt in the Eastern Mediterranean. Around Malatya and Elazig areas (SE Turkey), they are found within imbricated slices of a melange complex, known as the Yuksekova Complex. The studied basaltic rocks are common members of this melange complex, and show distinctive features of sources with tholeiitic to tholeiitic-transitional character. Petrography, whole-rock trace element and isotopic data reveal two different compositional groups. Group I is transitional between island arc tholeiites and normal mid-ocean ridge basalt, and Group II includes back-arc (BABB), enriched mid-ocean ridge (E-MORB), and ocean island basalt type (OIB) compositions. According to the known Late Cretaceous stratigraphic ages, the studied basaltic rocks have (Sr-87/Sr-86)(i) = 0.7036660-0.706394, (Nd-143/Nd-144), = 0.512734-0.512927, Pb-208/Pb-204 = 38.3216-39.3400, Pb-207/Pb-204 = 15.5018-15.6262 and Pb-206/Pb-204 = 18.5655-19.3209. In addition, epsilon Nd-i values vary between +3.99 and +8.01 with two-stage T-DM values ranging from 0.25 to 0.59 Ga. In the Sr versus Nd isotope correlation diagram, most samples plot along the mantle array line. In the correlation diagrams of Pb-206/Pb-204 versus Pb-208/Pb-206 and Pb-207/Pb-206, the rock samples also plot nearly on the Northern Hemisphere Reference Line, similar to Atlantic and Pacific Ocean ridge basalts. As a whole, the isotopic data reveal that the studied rocks were derived from a depleted mantle source.