Bulletin of the Mineral Research and Exploration (BMRE)
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Coal quality, mineralogy, petrography, and geochemistry of the high-strontium Bozburun lignite (Malatya, eastern Türkiye)
No full textThe Bozburun coalfield hosts a late Miocene 1.1 m thick coal seam. This study aims to determine coal quality, mineralogy, petrography and geochemistry, and controlling factors of elemental enrichments. The coals are generally black and greyish black in colour, and the low part of the seam commonly includes fossil shell remains. The ash yield displays a decreasing trend towards the upper part of the seam; in turn, gross calorific and total C values increase upwards. The total S content being generally higher than 5% (on dry basis), displays an increasing trend towards the upper part. In the entire seam, huminite is the most common maceral group, while inertinite and liptinite display variable proportions. The identified minerals by XRD are mainly quartz, clay minerals, calcite, pyrite, and aragonite (in fossil shell remains-bearing samples), whereas feldspars and marcasite determined in a few samples. Furthermore, in the coal samples, celestine and barite were identified by SEM-EDX. This study indicates that precipitation of celestine and Sr-bearing barite grains during diagenetic stage and Sr-uptake by mollusc within the palaeomire caused Sr enrichment in the entire seam. Overall, the water influx and redox conditions controlled the mineralogical and the elemental compositions of the coal seam
Porphyry and epithermal Au-Cu systems of the Southern Caucasus and Northern Iran
No full textThis article presents tangible geological evidence for the coexistence of porphyry copper and epithermal gold systems within single polygenic deposits and provides a paleothermophysical model for their origins. A brief metallogenic analysis of the Southern Caucasus and Northern Iran has shown that such deposits are confined to long-living calc-alkaline island arcs and were formed during their orogenesis. Examples of complex Sonajil (Iran), Gharta, and Merisi (Georgia) deposits are considered. The investigation has shown that for combined porphyry and epithermal ore formation, some preconditions are suggested to exist: (i) a source of anomalous energy that exceeds the thermodynamics of the enclosing environment; (ii) the existence of a temperature gradient that determines conventional flows of fluids composed of endogenous and meteoric constituents (proven by rhythmical zoning of ore lodes); (iii) the stability of such conditions for a period of sulfide ore formation. However, such a process of sulfide ore formation cannot explain the formation of high sulfidation gold deposits. The precipitation of native gold requires phreatic collapse in the ore conduit channel, already after the formation of hydrothermally altered rocks, and this event results in the creation of either hydrothermal breccias often with jigsaw-fit texture or brecciated vuggy silica where host rocks and hydrothermally altered rocks are cemented by a gold-bearing quartz matrix
Investigation of the change in the characteristic properties of epoxy and silane coated natural stone surfaces
No full textTravertine is a natural stone with macro and micropores; these pores are connected by capillary means. Their visual appearance and porous structure add a different style and diversify their usage areas. However, the large pore structure of travertine brings some limitations in determining the usage areas. In the study, protective solutions called silane and epoxy, which provide protection against water, were used to prevent and/or minimize decomposition in areas of use, depending on the porosity of the travertine, and their effects on travertine were compared. Treatment of both chemicals separately on the travertine surface was carried out by spraying, applying with a brush, and dipping into chemicals. With the findings obtained from the physical examinations after curing, the work continued using the applying and dipping method. The dipping method was evaluated with the chemical’s 10, 20, and 40-minutes waiting times. The study found that the best application condition was chemical immersion for 10 minutes. However, in SO2 wear experiments, it was understood that surfaces treated with epoxy were more durable due to the high viscosity of the chemical. As a result, it has been determined that silane application provides more effective surface protection results than epoxy
Determination of Atterberg Limits using the vane shear test method
No full textAtterberg limits are important index parameters used to classify soils for various engineering applications. Engineering properties of soils are predicted through simple correlations with index properties and thereby the engineering behavior of soils are qualitatively assessed. There are two popular methods of determining liquid limit, and plastic limit is commonly determined adopting rolling thread methods. To avoid operator related variations in determining plastic limit by conventional method, some researchers have explored using cone method as an alternative. However, there is no consensus about the depth of penetration to reckon the end of plastic state. Though various other test methods have been developed to determine plastic limit (like roll plate device), cone penetration with its limitation of determining plastic limit, is the only method to determine both liquid and plastic limit of soils. Since laboratory vane shear test is a simple and reliable method of determining undrained strength of fine-grained soils, the authors have explored to determine both liquid and plastic limits through correlations developed between undrained strength and water content over a range of consistencies between liquid and plastic states. This would eliminate determining liquid and plastic limit separately without sacrificing the reliability of results
Determination of the relationship between tectonic and karstification using morphometric indices in Bozburun Peninsula, Marmaris, Türkiye
No full textBozburun Peninsula (Marmaris) attracts attention due to its various karst shapes on limestones of different ages. It is also located in an important region in terms of tectonic activity. In this study, the distribution of karst shapes determined by satellite images, topographic maps and field studies was examined. In this context, the elevation ranges (m), base and hillslope angles (%), depth (m) and pitting rates (RP), elongation ratio (RE) and directions (EA α) of the relevant shapes were determined. Then, the relationship between the faults and the quantitative results obtained was interpreted. Remote Sensing (RS), Geographic Information System (GIS) technologies, calculations and field observations used in the study; it enabled us to reveal that there is a close relationship between karstic formations such as polje, uvala and doline and geological structures such as faults, diaclasis, folds and Nappe windows. Available data also show that geological structures have a positive effect on karstification in the study area
Reservoir characteristics of the middle Eocene Avanah Formation in Erbil governorate, northern Iraq: Integration of outcrop and subsurface data
No full textThe current work investigate the petrophysical characteristics of the Middle Eocene Avanah Formation in the Erbil Governorate using IP software to analyze the well data, integrated with the petrographic investigation of the formation in the nearest outcrop in the Gomaspan section. Well logging data revealed that the main lithology of the formation is limestone and dolostone while the lithology in the Gomaspan section is composed of limestone, dolomitic limestone, marly dolomitic limestone, and thin beds of shale. The lower dolomitic unit in the subsurface section of the formation is believed to be the most suitable reservoir unit due to good petrophysical characteristics including, low water saturation, high porous medium, and the presence of movable hydrocarbon. To measure porosities, a variety of well logging techniques were used in this study. The investigated formation was divided into Avanah dense (limestone unit) and Avanah porous (dolostone unit) based on their porous components. The petrographic study shows that most pore types of the formation are secondary and represented mainly by vuggy, moldic, intercrystalline, and fracture types. Most of the fractures in the upper limestone units are filled by calcite cement. The study claimed that the lower part of the formation (dolostone unit) in both sections is considered a good reservoir
Problems in dating results on lake sediments: Türkiye
No full textIn the dating process on the study of earth sciences, one of the basic assumptions is the equilibrium in the amount of carbon between terrestrial samples and the atmosphere. Most radiocarbon dating results are prepared regarding to this assumption. Although it is frequently used, some invalid situations can be encountered during the subaquatic studies. Recent water samples, aquatic plants, and remnant of animals may present different ages than the actual age. Another problem using the age-depth model is how many dating results should we be used to ensure high accuracy of the model. We also present our field study results about the number of dating points. The aim of this study is to explain how we could solve the problem in dating the freshwater reservoir effect over for short and longtime durations. In order to eliminate the freshwater reservoir effect, the terrestrial material must be dated. Thus, the carbon in the organic material is not affected by the dissolved carbon in the water. The circumstances significantly improve the age-depth models accuracy
Neotectonics and geothermal potential of the East Anatolian Tectonic Block: A case study in Diyadin (Ağrı) geothermal field, NE Türkiye
No full textDiyadin is situated 71 km ESE of Ağrı nearby the Turkish-Iranian State border in the east Anatolian tectonic block. It is only one of several type localities of promising geothermal fields in eastern Anatolia. The neotectonic regime and related fault zones in the Eastern Anatolia are dominated by a strike-slip tectonic regime governed by a stress field state, in which the greatest principal compressive stress (σ1) is operating in NNW direction (N22°W) while the least principal stress axis (σ3) or extension direction is N68°E. This stress field state was proved once more by the tensor solution of the 12 June 2022 Akçift (Muradiye-Van) earthquake of Mw = 5.1. The strike-slip neotectonic regime started at the time of latest Pliocene-early Quaternary and then triggered the first occurrence of the fissure eruption along the NNW trending Kaletepe open fracture. This event was followed by the development of both the two-peaked Tendürek strato-shild volcano and the Diyadin geothermal field (DGF). The most common manifestations of the DGF are the active tectonic regime and related faults, active volcanoes, fumeroles, numerous hot water springs to artesian wells, widespread ironrich alteration zones, actively growing fissure-ridge travertines and the probable presence of the shallow-seated and unroofed hypabyssal felsic to intermediate intrusions of Quaternary age
Neotectonics of Türkiye and its geothermal implication
No full textFavorable conditions for geothermal energy were created in Türkiye during its neotectonic episode from Neogene to Quaternary. This episode is characterized mainly by fluvio-lacustrine sedimentation and strike-slip tectonics with associated magmatism. Under these conditions, a great number of geothermal areas have formed in the neotectonics provinces in association with major tectonic features, including the North and East Anatolian Fault Zones (NAFZ and EAFZ, respectively). Today, the geothermal resources of Türkiye are mainly located in the West Anatolian Extensional Province associated with the graben systems. However, the Central Anatolian Ova Neotectonic Province is considered one of the most promising geothermal targets which are characterized by the presence of widespread hot dry rock systems. This study mainly aims to throw light on the possible potentiality of these resources at Kırşehir Block by emphasizing the neotectonic evolution of the country
A brief overview on geothermal scaling
No full textHot spring waters are rich in terms of minerals. Since there are dramatic changes in thermodynamic parameters in geothermal power plants, such as a decrease in temperature and pressure, severe precipitation occurs throughout the system components in an uncontrolled manner. There are three main chemistries in deposits: carbonates (mainly calcium carbonates), silicates (metal silicates), and sulphides (antimony sulphide-stibnite). Energy harvesting is remarkably reduced out of the insulating nature of the deposit. Various actions need to be taken to mitigate this undesirable issue of scaling in geothermal systems. Geothermal systems are in fact quite complex, and the composition of brine and, accordingly, the chemistry of the deposit are not identical. Therefore, each system should be studied individually, and a tailor-made remedy should be developed. In this overview, the types of deposits in terms of chemistry and the actions (pH modification or antiscalant dosing) that should be taken to reduce scaling are mentioned, and potential chemistries of antiscalants are given