Provenance of a large Lower Cretaceous turbidite submarine fan complex on the active Laurasian margin: Central Pontides, northern Turkey

Remziye Akdoğan*, Aral I. Okay, Gürsel Sunal, Gabor Tari, Guido Meinhold, Andrew R.C. Kylander-Clark

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

33 Citations (Scopus)

Abstract

The Pontides formed the southern active margin of Laurasia during the Mesozoic. They became separated from mainland Laurasia during the Late Cretaceous, with the opening of the Black Sea as an oceanic back-arc basin. During the Early Cretaceous, a large submarine turbidite fan complex developed in the Central Pontides. The turbidites cover an area of 400 km by 90 km with a thickness of more than 2 km. We have investigated the provenance of these turbidites—the Çağlayan Formation—using paleocurrent measurements, U-Pb detrital zircon ages, REE abundances of dated zircons and geochemistry of detrital rutile grains. 1924 paleocurrent measurements from 96 outcrop stations indicate flow direction from northwest to southeast in the eastern part of the Çağlayan Basin and from north-northeast to west-southwest in the western part. 1194 detrital zircon ages from 13 Lower Cretaceous sandstone samples show different patterns in the eastern, central and western parts of the basin. The majority of the U-Pb detrital zircon ages in the eastern part of the basin are Archean and Paleoproterozoic (61% of all zircon ages, 337 grains); rocks of these ages are absent in the Pontides and present in the Ukrainian Shield, which indicates a source north of the Black Sea. In the western part of the basin the majority of the zircons are Carboniferous and Neoproterozoic (68%, 246 grains) implying more local sources within the Pontides. The detrital zircons from the central part show an age spectrum as mixture of zircons from western and eastern parts. Significantly, Jurassic and Early Cretaceous zircons make up less than 2% of the total zircon population, which implies lack of a coeval magmatic arc in the region. This is compatible with the absence of the Lower Cretaceous granites in the Pontides. Thus, although the Çağlayan Basin occupied a fore-arc position above the subduction zone, the arc was missing, probably due to flat subduction, and the basin was largely fed from the Ukrainian Shield in the north. This also indicates that the Black Sea opened after the Early Cretaceous following the deposition of the Çağlayan Formation.

Original languageEnglish
Pages (from-to)309-329
Number of pages21
JournalJournal of Asian Earth Sciences
Volume134
DOIs
Publication statusPublished - 1 Feb 2017

Bibliographical note

Publisher Copyright:
© 2016 Elsevier Ltd

Funding

This study was supported by TÜBİTAK grant 109Y049 , TÜBİTAK grant 113R007 , TÜBİTAK 2214 -A research abroad fellowship program and by TÜBA. The field expenses were funded by ITU Division of Scientific Research Projects for PhD students (project no. 37264). Constructive reviews by Alastair Robertson and Inga Sevastjanova improved the manuscript. We also thank Evren Çubukçu for help with the cathodoluminescence images of zircons, Cansu Demirel and Muhammed Ali Kuru for company during field and Nurullah Kızılay for help during the mineral separation.

FundersFunder number
ITU Division of Scientific Research Projects37264
TÜBİTAK109Y049, 113R007

    Keywords

    • Black Sea
    • Central Pontides
    • Detrital zircon
    • Early Cretaceous
    • Paleocurrent
    • Provenance

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