Au-rich bimodal-mafic type volcanogenic massive sulphide deposit associated with Jurassic arc volcanism from the Central Pontide (Kastamonu, Turkey)

Kurtuluş Günay*, Vural Oyan, Cahit Dönmez, Buğra Çavdar, Emin Çiftçi, Andrey V. Chugaev, Nail Yıldırım, Osman Parlak, Esra Yıldırım, Lian Xun Wang, Chang Qian Ma

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

The central part of the Pontide Orogenic Belt, located in northern Anatolia, is a segment of the Alpine-Himalayan orogeny. Çangaldağ Metamorphic Complex (CMC) occurs within this segment which consists of ensimatic island arc volcanics and deep sea sediments which occasionally cut cross by mafic sills/dykes. They were exposed to metamorphism under the greenschist facies conditions and remain in tectonic contact with each other. The Say yayla mineralization is one of the recently discovered volcanogenic massive sulfide (VMS) deposits in the CMC with a remarkable Au content. The mafic and felsic metavolcanic rocks are the host-rocks of the Say Yayla mineralization and the ages determined by U-Pb zircon grains of these felsic volcanic rocks range from 170 Ma to 165 Ma indicating Middle Jurassic time. At the 0.1% cut-off grade, 7.5 million tons of resource has been calculated with 0.75 ppm Au, 0.65 wt% Cu, and 0.35 wt% Zn grades. The Say Yayla mineralization consists of massive and semi-massive sulfide minerals and a mineral assemblage represented by predominantly pyrite and chalcopyrite and trace amounts of sphalerite, tennantite and galena. Average base and precious metal grades of the zones occur with >1 wt% Cu are 2 wt% for Cu, 0.7 wt% for Zn, 0.04 wt% for Pb and 1.5 g/t for Au. The sulfur isotope values (δ34S VCDT) range from 4.9‰ to 6.7‰ for pyrite grains and 4.2‰ was obtained from the one sphalerite sample. δ18O values for the quartz from quartz-rich ore samples were 10.6 ‰ and 11.7‰ δ18O (VSMOW)qtz. δ18O (VSMOW)fluid values for the ore-forming fluids vary between 0‰ and 2.4‰. Lead isotope compositions of the pyrite minerals were 18.148–18.150 (206Pb/204Pb), 15.548–15.550 (207Pb/204Pb) and 38.078–38.083 (208Pb/204Pb) The geological, geochemical, and isotopic data of the ore and host-rocks reveal that the mineralization is a bimodal-mafic type (Noranda type), which is classified into Cu-Zn group of volcanogenic massive sulfides. Geochemical and geochronological data from the wall rocks further show that mineralization was developed within an ensimatic island arc environment during the Middle Jurassic.

Original languageEnglish
Article number104660
JournalOre Geology Reviews
Volume141
DOIs
Publication statusPublished - Feb 2022

Bibliographical note

Publisher Copyright:
© 2021 The Authors

Funding

This study was completed as a part of the “Metallic Mineral Explorations around Central and Western Black Sea Region Project” (numbered 2011-2021/32-13-01-04) run by MTA (General Directorate of Mineral Research and Exploration, Ankara, TURKEY). We would like to thank the Co editor-in-chief Franco Pirajno, Huayong Chen, Associate editor İbrahim Uysal and anonymous reviewers who contributed to the development of this article with their criticisms. We thank Paul A Schroeder for the English language editing of the article. Contributions from geological engineers; Cüneyt Baran, Kenan Coşkun, Aysun Sözcü and Dr. Serdar Keskin in the field were much appreciated. Also, we were very thankful to Mustafa Tokoğlu and Tuğba Birgül for their efforts and contributions during the resource estimation processes. Last but not the least, there was a great team behind all the work carried out in MTA. Thank you wholeheartedly to this great team, whose names are too many to write.

FundersFunder number
Cüneyt Baran
Kenan Coşkun
Mount Allison University

    Keywords

    • Bimodal-mafic type
    • Central Pontide
    • Say Yayla
    • Volcanogenic massive sulfides

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