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- Yüksek Lisans TeziAçık Erişim2023Göksel (Hayrat-Trabzon) Cu-Fe skarn cevherleşmesinin mineralojik, petrografik ve jeokimyasal özelliklerinin incelenmesi
İhsan Gökalp
Göksel Cu-Fe skarn cevherleşmesi Trabzon ili, Hayrat ilçesi, Göksel Mahallesi sınırları içerisinde yer almaktadır. Göksel skarn cevherleşmesinin yer aldığı sahada alttan üste doğru Hamurkesen Formasyonu (Liyas), Berdiga Formasyonu (Üst Jura-Alt Kretase), Çatak Formasyonu (Geç Kretase), Kaçkar Granitoyidi (Geç Kretase-Eosen (?)) yer almaktadır. Kaçkar Granitoyidi tüm bu birimleri kesmekte olup Berdiga Formasyonu'na ait kireçtaşı dokanaklarında kontakt metamorfizmaya bağlı olarak skarn cevherleşmesinin gerçekleşmesine sebep olmuştur. Çalışma alanının en genç birimleri ise tüm birimleri kesen Kretase-Eosen (?) yaşlı dayklardır. Skarn tip cevherleşmenin endoskarn zonunda piroksen, granat, manyetit ve epidot az miktarda iken, ekzoskarn zonunda ise bu mineral fazladır. Göksel Cu-Fe skarn cevherleşmesinin mineral parajenezi manyetit, pirit, pirotin, sfalerit, kalkopirit, galenit, hematit, arsenopirit, mangan, molibdenit, sfen, rutil, ilmenit, makinevit (vallerite), wolframit, gümüş ve tellürden oluşmaktadır. Göksel Cu-Fe skarn sahasındaki granitoyidler kalk-alkali bileşiminde ve metalimünyum karaktere sahip olup, genel olarak volkanik yay granitoyidler ve geç çarpışma sonrası granitoyidler ile benzerlik göstermekte ve yitim sonrası meydana geldiği düşünülmektedir. Çalışma alanındaki granatların SEM-EDS analizi sonucuna göre andradit ve grossular andradit bileşiminde oldukları, piroksenlerin hedenberjit, diyopsit ve hedenberjitik diyopsit olduğu tespit edilmiştir. Çalışma alanındaki skarn minerallerinin bileşiminin Cu ve Fe yataklanma sınıfına uyduğu belirlenmiştir. Göksel Cu-Fe skarn cevherleşmesinin ekzoskarn zonundaki granat ile epidot minerallerine uygulanan sıvı kapanım çalışmaları, granat kristallerdeki birincil kökenli iki fazlı (sıvı+gaz) kapanımlardan homojenleşme sıcaklıkları 340-434 oC ve tuzluluğunun %7,9-11.5 NaCl (eşdeğer tuzluluk) arasında, epidot mineralinden elde edilen homojenleşme sıcaklıklarının ise 287-312 oC arasında oldukları tespit edilmiştir. Skarn oluşumuna sebebiyet veren sıvıların NaCl-CaCl2 bileşimli sıvıların varlığından kaynaklandığı düşünülmektedir.
- MakaleYalnız künye2020Scopus SJRQ2Geochemical composition of magnetite from different iron skarn mineralizations in NE Turkey: implication for source of ore-forming fluids
Sipahi, Ferkan; Gücer, Mehmet Ali; Saydam Eker, Çiğdem
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.
AtıfScopus17WoS10OpenAlex19
İncele - MakaleYalnız künye2011Scopus SJRQ3Formation of skarns at Gumushane (Northeastern Turkey)
Sipahi, Ferkan
Skarn deposits are located in the NE Black Sea region of Turkey belonging to the Alpin metallogenic province. The Fe skarn deposit at Arnastal is hosted by Late Cretaceous carbonate rocks comprised of limestone and the skarn occurrence at Camibogazi dolomitic limestone, adjacent to the Eocene Zigana Granitoid. The prograde textures include rhythmic banding, spots, and mossiness, and the retrograde textures are shock-induced and brecciated. These are identified in the Fe skarn deposit at Arnastal, where there are mineral parageneses of andradite, actinolite, tremolite, epidote, quartz, magnetite, and hematite, and less pyrrboune and pyrite. Additionally, well-crystallized vesuvianite, well-crystallized phlogopite, and diopside in the skarn occurrence. at Camibogazi are identified. Some of the skarn minerals are calcic and have high Mg/(Mg + Fe) ratios. Clinopyroxene consists of diopside (Di(96.66-99.04)Hd(0.67-2.80)Jo(0.29-0.55)). Vesuvianite is mostly Mg-rich, and has a very low MnO content (<0.1 %). Other skarn minerals are Fe-rich. Garnet is characterized by oscillatory zoning and has an andradite composition (Ad(72)Gr(28) to Ad(98)Gr(2)). Epidote has an Fe content of 8.96 to 12.42 wt%. Magnetite is generally massive and sporadically banded with some martitization. The formation temperatures of skarn minerals range from 330 to 600 degrees C. In addition, mass change calculations from the granitoid and andesite toward the skarn zone indicate that there is considerable mass transfer of Si, Al, Fe, and Mg to the carbonate rocks during skarn formation. The average mass changes are estimated at a depletion of 41 g/100 g in granitoid and a gain of 8 g/100 g in andesite. Fe skarn deposit and skarn occurrence are characterized by early, high-temperature mineral assemblages dominated by the anhydrous minerals garnet and diopside and late low-temperature assemblages with hydrous minerals, such as vesuvianite, phlogopite, and epidote. The type of garnet and the abundance of magnetite with minor pyrite suggest that the Fe skarn deposit at Arnastal forms under relatively oxidized conditions. The type of clinopyroxene in the skarn occurrence at the Camibogazi shows oxidized skarns.
AtıfWoS26OpenAlex37İncele