Geochemical composition of magnetite from different iron skarn mineralizations in NE Turkey: implication for source of ore-forming fluids
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Iron oxide mineralizations in the eastern part of the Pontides (NE Turkey) are hosted in the skarn environments which are the Pontide paleomagmatic arc. These mineralizations always occur in the contacts between granitoid and limestone. Magnetites are hosted in carbonate rocks and generally formed during garnet-magnetite-epidote-quartz phase. Magnetites have high Co (15.8–43.4 ppm for the Kopuz, 11–12.5 ppm for the Eğrikar, and 3.8–1266.7 ppm for the Karadağ) concentrations suggesting that the sulfide decreased from the early to the late phases in the iron skarn mineralization forming systems. The Co/Ni ratios in the magnetites (0.12 to 35.38 for Karadağ, 2.19 to 13.53 for the Kopuz, and 2.39 to 5.21 for the Eğrikar) show the hydrothermal effect on the magmatic source in iron skarns in the study area. Thus, variable Co/Ni ratios reflect interactions between the magma with the host rock during successive alteration stages. Magnetites in this study have Sc-Nb-Mg-Ti depletions and Ta enrichment. In this study, high Co, Ti, and V contents in magnetites suggest the high temperature (300–500 °C) and low ƒO2. The V contents of the magnetite in the Karadağ increase with the decreasing oxygen fugacity of fluid(s) forming magnetites, whereas the V contents of the magnetites in the Kopuz and Eğrikar decrease with increasing oxygen fugacity of fluid(s) forming magnetites. Element patterns and Ni/Cr ratio (< 1) of the magnetite are geochemically similar to those of magnetite in Fe-skarn deposits and partly magmatic accessory magnetite of I-type granites. As a result, the Co, Ni, V, and Ti elements of the magnetite have played an important role in the discriminating and interpreting of skarn mineralizations in the eastern Pontides and support a calcic skarn origin with studies of the mineralization geology.
KeywordsMagnetite Oxygen isotope Skarn Trace elements NE Turkey
The authors thank Tanju Aydurmuş for his help during the fieldwork. We would like to thank the anonymous reviewers for their constructive criticism and valuable comments, which improved the quality of the paper. We are also grateful to the editorial handling of Domenico M. Doronzo and Abdullah M. Al-Amri for their helpful feedback and timely processing of the submissions.
A part of this study was supported by The Scientific and Technological Research Council of Turkey (114Y013 and 114Y099 numbered TÜBİTAK projects).
- Arslan M, Tüysüz N, Korkmaz S, Kurt H (1997) Geochemistry and petrogenesis of the eastern Pontide volcanic rocks, Northeast Turkey. Chem Erde 57:157–187Google Scholar
- Çiftçi E (2011) Sphalerite associated with pyrrhotite-chalcopyrite ore occurring in the Kotana Fe-skarn deposit (Giresun, NE Turkey): exolutions or replacement. Turkish J Earth Sci 20:307–320Google Scholar
- Kaygusuz A, Arslan M, Siebel W, Sipahi F, İlbeyli N, Temizel İ (2014) LA-ICP MS zircon dating, whole-rock and Sr-Nd-Pb-O isotope geochemistry of the Camiboğazı pluton, Eastern Pontides, NE Turkey: implications for lithospheric mantle and lower crustal sources in arc-related I-type magmatism. Lithos 192-195:271–290CrossRefGoogle Scholar
- Makvandi S, Ghasemzadeh-Barvarz M, Beaudoin G, Grunsky EC, McClenaghan MB, Duchesne C (2016) Principal component analysis of magnetite composition from volcanogenic massive sulfide deposits: case studies from the Izok Lake (Nunavut, Canada) and Halfmile Lake (New Brunswick, Canada) deposits. Ore Geol Rev 72:60–85CrossRefGoogle Scholar
- Okay AI, Tüysüz O (1999) Tethyan sutures of northern Turkey. In: Durand B, Jolivet L, Horváth F, Séranne M (eds) The Mediterranean basins: tertiary extension within the Alpine orogen. Geol Soc London Spec Publ 156:475–515Google Scholar
- Pejatoviç S (1979) Metallogeny of the Pontid-Type Massive Sulphide Deposits, Mineral Geochemistry of Massive Sulphide-Associated Hydrothermal Sediments of the Brunswick Horizon, Bathurst Mining Camp, New Brunswick. Can J Earth Sci 33:252-283.Google Scholar
- Rudnick RL, Gao S (2003) Composition of the continental crust. Treatise on Geochemistry 3:1–64Google Scholar
- Sipahi F (2011) Formation of skarns at Gümüşhane (northeastern Turkey): Neu Jb Mineral, Abh 88(2):169–190Google Scholar
- Sipahi F, Sadıklar MB (2014) Geochemistry of dacitic volcanics in the eastern pontides (NE Turkey). Geochem Int 4:329–349Google Scholar
- Sipahi F, Akpınar İ, Saydam Eker Ç, Kaygusuz A, Vural A, Yılmaz M (2017) Formation of the Eğrikar (Gümüşhane) Fe–Cu skarn type mineralization in NE Turkey: U–Pb zircon age, lithogeochemistry, mineral chemistry, fluid inclusion, and O-H-C-S isotopic compositions. J Geochem Explor 182(Part A):32–52CrossRefGoogle Scholar
- Sipahi F, Kaygusuz A, Saydam Eker Ç, Vural A (2018) Investigation of granitoids induced skarn mineralisations (Gümüşhane, NE Turkey): their geology, geochemistry and geochronology. In: Tubitak 1001 project, No: 114Y099, Ankara, TurkeyGoogle Scholar
- Tokel S, Köprübaşı N, Uysal İ, Van A (2011) Occurrences and genesis of Fe-skarn in relation to tectonic environment in E-NE Anatolia: geochemical consideration. N Jb Miner Abh 188(2):141–149Google Scholar
- Wen G, Li JW, Albert H, Hofstra AE, Koenig HA, Lowers DA (2017) Hydrothermal reequilibration of igneous magnetite in altered granitic plutons and its implications for magnetite classification schemes: insights from the Handan–Xingtai iron district, North China Craton. Geochim Cosmochim Acta 213:255–270CrossRefGoogle Scholar
- Yılmaz Y, Tüysüz O, Yiğitbaş E, Genç ŞC, Şengör AMC (1997) Geology and tectonic evolution of the Pontides, regional and petroleum geology of the black sea and surrounding region. Am Assoc Pet Geol Bull 68:183–226Google Scholar