Yazarlar
- Sipahi, Ferkan(2)
- Akpınar, I.(1)
- Arslan, M.(1)
- Aslan, Z.(1)
- Glagolev, S(1)
- Sadıklar, M.Burhan(1)
- Çiftçi, E.(1)
Yayınlar
- MakaleYalnız künye2019Nature of tourmaline formation in quartz porphyry in the E Sakarya zone (NE Turkey): Geochemistry and isotopic approach
Sipahi, Ferkan
Tourmaline, which exhibits important differences in terms of texture and composition, is found in 44 My aged quartz porphyry from Karadağ in the eastern Pontide (NE Turkey). Tourmaline has high Al and Mg contents and is the chemical zoning; it contains Mg that can substitute for Fe and/or Al in the Y site and X-vacancy that can replace Na in the X site from the core to rim. Tourmaline, classified as dravite component, has low Fe content and very low Ca content. The V (112-510 ppm) and Sr (37.3-147.1 ppm) contents of tourmalines related to quartz porphyry are in conformity with metamorphic and magmatic tourmalines. Tourmalines have similar rare earth elements (REEs) but lower heavy REE contents than host quartz porphyry. The δ18O and δD values of tourmalines are relatively narrow, ranging from 5.7 to 8.5% V-SMOW and from -58 to -72% V-SMOW, respectively, consistent with primary magmatic water. The oxygen-isotope thermometry calculation of quartz and tourmaline pair yields equilibrium formation temperature of 432 °C. The formation of tourmaline shows a post magmatic origin, confirming magmatic fluid cooling and fluid-rock interactions.
- Kitap BölümüAçık Erişim2019Ore Mineralogical Study of Cerattepe Au-Cu (±Zn) VMS Deposit (Artvin-Turkey)
Akpınar, I.; Çiftçi, E.; Glagolev, S
The Cerattepe mine, one of the volcanogenic massive sulfide deposits in northeastern Turkey, is hosted within the late Cretaceous volcanic, intrusive and sedimentary rocks. Deposit’s main ore body contains high-grade massive copper sulfides and a gold-silver and barium rich oxide zone, characterized by dense alteration stages, is situated on top of it. Replacement, cataclastic, breccia, dissemination, dendritic, concentric growth, colloform, and framboidal textures were identified. Pyrite, sphalerite, marcasite, chalcopyrite, bornite, galena, tennantite-tetrahedrite, gold, covellite, digenite, chalcocite, cuprite and cubanite constitute the mineral paragenesis where quartz, calcite and barite account for the gangue minerals. Limonite, hematite, lepidocrocite, malachite, azurite and jarosite developed in the oxidation zone.
- MakaleYalnız künye2014Geochemistry of dacitic volcanics in the Eastern Pontides (NE Turkey)
Sipahi, Ferkan; Sadıklar, M.Burhan
Dacitic rocks that crop out around the Zigana Mountain (Gümüşhane) in the eastern Pontide (NE Turkey), are mainly composed of quartz, plagioclase, sanidine, amphibole, muscovite, and biotite as the main minerals. Zircon and rutile are the accessory minerals. Pyrite, chalcopyrite, and covellite are the opaque components. On the basis of trace-element data, dacites have been classified as Dacite-I and Dacite-II. Dacite-I is tholeitic-transitional, whereas Dacite-II is transitional-calc-alkaline. The geochemical variation can be explained by the fractionation of the common mineral phases, such as plagioclase, hornblende, magnetite, and apatite. Dacites also show island-arc properties, with negative Nb, Sr, P, and Ti anomalies. The trace-element distrubitions of the dacitic rocks reflect the typical characteristics of rocks from the subduction-related tectonic setting, with enrichment of large-ion lithofile elements and light rare-earth element, but depletion in high-field-strength elements. The dacitic rocks are developed through plagioclase ± hornblende-controlled fractionation from the same parental magma that settled in two successive stages and are derived from an enriched source, probably by the mixing of slab-derived and lithospheric melts.
- MakaleYalnız künye2006Mineralogy, petrography and whole-rock geochemistry of the Tertiary granitic intrusions in the Eastern Pontides, Turkey
Arslan, M.; Aslan, Z.
Granitic intrusions in Eocene and post-Eocene volcanic rocks outcrop in the Northern and Southern Zones of the Eastern Pontides, NE Turkey. Intrusions in the Northern Zone extend NW-SE whereas those in the Southern Zone are nearly E-W orientated. The contacts of the intrusions with the volcanic rocks are sharp, epidotized and include volcanic xenoliths. The margins of Southern Zone intrusions often contain abundant angular mafic microgranular enclaves of diorite to quartz diorite composition. The rocks also show evidence of mingling and mixing between coeval mafic and felsic magmas. Field observations suggest a stopping type of ascent and emplacement style for the intrusions. Petrographically, intrusions show variations in both colour and mineralogy with fine to medium granular, monzonitic, poikilitic, rapakivi, anti-rapakivi and graphic textures. Based on modal mineralogy, the Northern rocks are monzonite, quartz monzonite, monzodiorite and quartz monzodiorite whereas the Southern samples are monzogranite and granodiorite. The rocks are generally calc-alkaline to mildly alkaline transitional and metaluminous, and show a CAFEMIC trend. The Northern Zone intrusions form a post-collisional, A-type, alkaline monzonitic association and Southern Zone intrusions form a post-collisional, I-type, granodioritic calc-alkaline-transitional association. Whole-rock compositional data indicate that differentiation occurred via fractional crystallisation with or without magma mixing. Incompatible and rare earth element patterns indicate that both the Northern and the Southern Zone intrusions were derived from melting of a mantle region enriched by subduction-related fluids but evolved differently during ascent and emplacement. U-Pb zircon dating in the Southern Zone yields an intrusion age of 44.4±0.3 Ma. Regional geodynamics indicates post-collisional extensional tectonics in the region. Crustal involvement and the level of emplacement may have been important for magmatic evolution, especially for the Southern Zone intrusions, after the cessation of subduction and subsequent crustal thickening.