Türkiye Jeoloji Bülteni

Abstract: Çakmakkaya and Damarköy copper deposits in Murgul (Artvin) area are the typical examples of Kuroko^type volcanogenic sulfide deposits thatwidely occur in the Eastern Pontide region of Turkey.Çakmakkaya and Damarköy deposits are occured in volcanic rocks in an upward sequence consist of andezitle lava, hrecciated dacite tuff, cov~ering tuff and porphry dacite. Stockwork ores are dominant in the deposits and are hosted by brecciated dacite tuff unit. A thin stratiform ore zoneand a gypsume lens are occured on the stockwork ore in the Çakmakkaya deposit, while Damarköy deposit contains only stockwork ore.Stockwork ore veinlets contain mainly pyrite and chalcopyrite, with minor amount of sphalerite, galena, tetrahetrite and marcasite. Quartz isthe only gangue mineral. Enrichment of sulfides is largely controlled by microfracturing of the dacitic tuffs. High contents occur especially at theintersections of the fractures.Stratiform ore zone occured within the Çakmakkaya deposit contains ore clasts which indicative of fragmentation and resedimentation of sulfideminerals during or after discharge of hydrothermal fluids onto the sea floor. Ore clasts contain the same minerals similar to that of stockwork ores.Fluid inclusion studies indicate that the ore forming fluids contain NaCl, CaCl2 andMgCl^ their salinities are high during the deposition of theore minerals and decrised toward the later episodes of mineralisation, temperature of the fluids reached up to 254.0 °C, but decreased down to 110.2°C during the later episodes of mineralisation.Oxygen and hydrogen isotope studies indicate that the most of the water in hydrothermal solutions are meteoric origine, however there seem tobe a small amount of sea water mixing and/or interaction.As a conclusion; it may be assumed that meteoric water, circulating through the underlying basement of the volcano-sedimentary rocks, has actedas mineralising fluid, and leached the metals (Fe, Cu, Zn, Pb etc.) and sulfur from the surrounding volcanic rocks and precipitated along the fractures within the brecciated dacitic host rocks and at the surface of the sea floor.

Abstract: 34 samples collected from the different depths of water between 0.50-68.00 m has been studied around Gökçeada (northern Aegean Sea).104 foraminiferal taxa belonging to 58 genera have been recognized in species level. These foraminifera however, show a remarkable differencealong the eastern and western coastlines of the island. Especially to the east of the island along the Aydıncık Cape there is a rich number ofPeneroplis planatus (Fichtel and Moll) and Peneroplis pertusus (Forskal). Also, to the south-east of Gökçeada the typical eastern Mediterraneanforaminifera Amphistegina lobifera Larsen and Sorites orbiculus Ehrenberg have been observed. Besides, a foraminiferal assemblage rich innumber and high in diversity has been idintified in 4 stations to the east and 3 stations to the west of the island.During another study between Gökçeada-Bozcaada-Çanakkale the genus Peneroplis, Amphistegina and Sorites have not been found. Also,along the Karaburun Peninsula, east of Çeşme (İzmir) in the İlıca Bay, there is a geothermal source with the temperature 55-58°C at a dept of2.50 m. Around this source there is an enrichment ofpeneroplids. Previous studies performed in the Gulf of İzmit, have demonstrated an extraordinart increase in the number and diversity of foraminifer a around the fault-related geothermal sources, which are not observed at the present.Thus, enrichment in the foraminifera in some stations may be explained by the geothermal effect

Abstract: Quartz veins are a common feature in many of the gold deposits and a major host to gold mineralisation. Various macroscopic textures areobserved in the epithermal quartz veins. According to the quartz textures within the vein, it can be discriminated whether the vein includes goldmineralisation or not. Two major textural groups are recognised: 1) Primary growth textures representing the open-space fillings; 2)Superimposed textures reflecting the overprinting events. Primary quartz vein textures are classified as buck, comb and banded textures.Superimposed textures are breccia and replacement textures. Minerals other than quartz such as adularia and carbonate minerals common inepithermal veins are useful to the interpretation of textural zones. In quartz veins a vertical textural zoning model can be defined according tothe pattern of distribution of textures and assemblages of textures. 

Abstract: A widespread, and intense hydrothermal alteration zone has developed in the Upper Cretaceous Şaplıca volcanics, in the northern part of theeastern Pontids, as a result of the intrusion of Late Cretaceous-Paleocene granitoids. Under strongly acidic, acidic, acidic-intermediate and intermediate alkaline conditions, propylitic, phyllic (sericitic), argillic (alunitization and kaolinization) alteration along with hematite and silica polymorphs, and two type oftuormaline mineralization developed under wide range of pH and Eh conditions.Alunite, kaolinite and silica are abundant in argillic alteration, whereas sericite dominates in phyllic alteration. Most of the major alunitedeposits are located along the periphery of the Şaplıca volcanic rocks and in addition contain alunite, kaolinite + quartz ± opal ± cristobalite.Illite, pyrite, barite, and gypsum also occur in small amounts.Major and some trace elements are notably concentrated in or were leached from, the volcanic rocks depending upon the alteration types. Ingeneral, Al + K and Mg + Ca + Fe were enriched in the alunitic + sericitic and propylitic alteration types, respectively. On the other hand, Ca,Mg and Fe were leached in the argillic alteration, and Fe was concentrated in hematite formation. Strong leaching ofNa was determined mainly for all alteration types. Silica generally decreased in argillic (e.g., in kaolinitic and alunitic) alteration zones. Most of trace elements weremobile during hydrothermal alteration. Y, Sc, Mo, Cr, Co, Ni, Zn tend to be mobile in acid aqueous systems and, thus, are nearly absent in thesealunitic alteration zones. In the swrounding kaolinitic envelope, these elements are present at background or slightly higher concentrations.Mainly Sr and partly Rb contents are higher in the alunic and kaolinitic zones than weakly altered parent rock. Barium content in the acidic alteration zones (alunitic and kaolinitic zone) is half about of the parent rock because of the relative insolubility of barite in acidic solutions. The lowest concentration of the element were determined in all the other alteration zones, and its content were strongly leached (about 1/10 to 1/20) fromthe weakly altered parent rocks. Pb and Cu content is increased in the propylitic zone. V is generally enriched in all alteration types comparedto weakly altered parent rocks. Such hydrothermal alteration zones can be used effectively to assess mineral exploration/evaluation of resourcesof similar alteration zones the eastern Black Sea region.

Abstract: The studied area is located in Keban township of Elazığ and two geological units are present in the area. These are from oldest to youngest;Keban Metaporphites (Permo-Carboniferous) and Keban magmatic rocks (Upper-Carbo-niferous).The Keban Metamorphics consist of calcshist, sericite chlorite schist, porous limestone, laminated limestone, bedded crystallized limestone,massive crystalized limestone olistolites.Keban magmatic rocks are occured alkaline siyenite, quartz siyenite, monzonite and quartz monzonite and intruded in to the KebanMetamorphics as dikes and sills.Although some minor variations major ore minerals are pirolusite, rodokrosite, barite, pyrite, galena, sphalerite, chalcopyrite, arsenopyrite, Ag-As-Sb sulphosalt and minor minerals; siderite, geothite, calcite, quartz, gypsium in different waste.Keban wastes are subdivided in to four main group (West Euphrates, Siftil Tepe, Zeytin Dağı, Derebaca) in Keban area.The samples are evaluated as mineralogically and geochemically. West Euphrate wastes are composed of oxidic ore and therefore showstrong Au-Ag and Au-Zn. Otherwise correlations among Au, Ag, Pb, Zn metals show significant connections between Ag, Pb and Zn of Siftil Tepeand these results match with those of Ag-rich Pb-Zn sulphide mineralizations. The same elements display similar correlations in Zeytin Dağıwastes. Correlation values for the same metals in Derebaca wastes are close to the above two wastes but very low Zn-Ag correlation value.