Petrology and zircon U-Pb geochronology of mafic - intermediate dykes in the West-Central Taurides: Implications for magma source during the Late Precambrian – Early Palaeozoic

ABSTRACT

Cadomian magmatic activity is represented by a mafic – intermediate dyke suits in the Karacahisar dome (West – Central Taurides) formed by the southward subduction of the Proto-Tethyan ocean beneath North Gondwana. These dyke suites are classified as diabase, andesite and dacite. They display calc-alkali, high-K calc-alkali and shoshonitic character, and intruded into the siliciclastic rocks deposited in a back-arc rift setting. In this study, we present new zircon U-Pb ages, Sr-Nd isotopic and geochemical data to better understand the petrological evolution of the Cadomian magmatism. Zircon U-Pb concordia ages of 551.3 ± 3.5 Ma, 557.9 ± 3.7 Ma and 569 ± 7.2 Ma were obtained for these dykes. On the N-MORB normalized spider diagrams, mafic – intermediate dykes exhibit enrichment in large ion lithophile elements (LILE: Sr, K, Rb, Ba, Th), relatively less enrichment in light rare earth elements (LREE: La, Ce and Nd) and depletion in high field strength (HFS: Tb, Ti, Y and Yb) elements. Dyke samples have significant depletions of Ta and Nb relative to neighbouring LILE and LREE and display a significant subduction component. On the chondrite normalized REE diagrams, a weak Eu anomalies are observed, and this indicates some plagioclase accumulation. Dyke samples fall into the volcanic arc (island arc and/or continental arc), and back-arc fields on tectonic setting discrimination diagrams. The εNd_(i) values of dykes range from −1.47 to 1.76, and Nd depleted-mantle model (T_DM) ages vary between 1.32 and 1.81 Ga, and show enriched mantle or metasomatized subcontinental lithospheric mantle source signatures. The primary magmas of the dykes were derived from amphibole- and garnet-bearing mantle, and were affected by fractional crystallization, mixing and assimilation processes during ascent through the upper crust. All available data show that this magmatic activity developed in a back-arc rift setting subsequent to Cadomian arc magmatism in the West-Central Taurides.

KEYWORDS:

• Anatolide-tauride block
• Cadomian magmatic events
• mafic-intermediate dyke
• back-arc rift

Acknowledgments

This study builds on the first author’s PhD thesis and was supported by the Scientific Research Projects Coordination Unit of Süleyman Demirel University Project No.: FDK-2018-6737 and YÖK-ÖYP Programme Project No: ÖYP05274-DR-14. We thank the Editor Prof. Dr. Robert Stern, Prof. Dr. Gültekin Topuz, Dr. Avishai Abbo, and an anonymous referee for helpful comments that significantly improved this manuscript. The authors also thank Assoc. Prof. Dr. Vural Oyan (Van Yüzüncü Yıl University) for his help during nature of mantle modelling.

Research Highlights

Cadomian magmatic activity in West-Central Taurides is represented by mafic - intermediate dykes.

These dykes are derived from the amphibole and garnet bearing metasomazited mantle, and were affected by fractional crystallization, mixing and assimilation.

All available data show that this magmatic activity developed in a back-arc rift setting subsequent Cadomian arc magmatism in the West-Central Taurides.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary material

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Additional information

Funding

This work was supported by the Süleyman Demirel Üniversitesi [FDK-2018-6737,OYP05274-DR-14].