Late Cretaceous arc magmatism in the Western Pontides (Turkey)–temporal and chemical changes

Ezgi Sağlam, Turgut Duzman, Cemre Ay, Aral I. Okay*, Gültekin Topuz, Gürsel Sunal, Ercan Özcan, Demir Altıner, Aynur Hakyemez, Jia Min Wang, Andrew R.C. Kylander-Clark

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)

Abstract

During the Late Cretaceous, a magmatic arc extended from the Lesser Caucasus through the northern margin of the Pontides into Srednogorie, Timok, Banat, and Apuseni (ABTS) in the Balkans for a distance of 2700 km. We studied the arc volcanic rocks in three regions in the Western Pontides and reviewed the geological data on the Lesser Caucasus-Pontide-ABTS magmatic arc, which shows several common features. Prior to the start of the arc magmatism, the region underwent uplift and erosion. New and published geochronologic and biostratigraphic data show that magmatism in the Lesser Caucasus-Pontide-ABTS arc started in the Turonian (ca. 93 Ma) peaked in the middle Campanian (80–78 Ma) and became rare and sporadic after the late Campanian (ca. 75 Ma). Magmatism was dominantly calc-alkaline to high-K calc-alkaline and shows typical subduction geochemical signatures. Late Cretaceous volcanism took place in a submarine and extensional environment. In the Lesser Caucasus-Pontide-ABTS belt, the arc volcanic rocks are overlain by Maastrichtian to Palaeocene marine limestones and sandstones, marking the end of the main phase of arc magmatism. However, in the Kefken region in the Western Pontides, Maastrichtian limestone sequence includes a volcanic horizon with a U-Pb zircon age of ca. 71 Ma. The Maastrichtian volcanic rocks show a more varied geochemistry than the older arc volcanic rocks, and include alkaline basalts, calc-alkaline basalts, and adakites. The coeval start of arc magmatism in the 2700-km-long Lesser Caucasus-Pontide-ABTS belt is related to the inception of the Africa-Eurasia convergence at ca. 96 Ma, which is also independently indicated by the beginning of intra-oceanic subduction, inferred from the ages of sub-ophiolite metamorphic rocks in Anatolia. The end of magmatism is linked to a marked decrease in the convergence rate during the Campanian, which was also partitioned between the northern and southern Tethyan subduction zones.

Original languageEnglish
Pages (from-to)947-970
Number of pages24
JournalInternational Geology Review
Volume66
Issue number4
DOIs
Publication statusPublished - 2024

Bibliographical note

Publisher Copyright:
© 2023 Informa UK Limited, trading as Taylor & Francis Group.

Keywords

  • adakites
  • Arc magmatism
  • geochemistry
  • Late cretaceous
  • Pontides
  • U-Pb zircon dating

Fingerprint

Dive into the research topics of 'Late Cretaceous arc magmatism in the Western Pontides (Turkey)–temporal and chemical changes'. Together they form a unique fingerprint.

Cite this