Bulletin of the Mineral Research and Exploration (BMRE)
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Metallogenic characteristics of some localities of gold mineralization along shear zones of Elgaab, Dum el Tor and Sodri - Um Bader, (Sudan)
No full textStudy area is located in the eastern sector of Saharan Meta - Craton that includes the western part of Bayuda Terrane and extend southwest to Sodri - Um Badir shear zones. The sector is dominated by metasediments, metavolcanic - sedimentary series represented by chlorite - schist, quartzite, calc - silicate, and marble. Low - grade metamorphic arc - related volcano - sedimentary sequence occurs as thin narrow bands and subjected to tectono - thermal events of Pan - African orogeny during the Late - Proterozoic era (900 - 550 Ma). All these rock sequences have been intruded by syn to Late Orogenic Granitoids and post - orogenic ring - shaped complex and felsic dykes. The intrusions are thought to be the source of hydrothermal fluids that caused the precipitation of gold. Similar characteristics of geological features and tectonic settings support the possibility of the extension of gold mineralization between shear zones. The comparison between the three gold mineralizations reveals variations in minerals assemblages, pathfinders and gold grade. The result of this study defines a new metallogenic province in the west of the River Nile, which occupies a very large area covered by Phanerozoic sediments. Numerous mineral deposits of economic potentiality have been targeted along the shear zones and related fractures and faults. Among those potential deposits, five of them have been chosen as targets for future gold exploration and evaluation.
https://doi.org/10.19111/bulletinofmre.69513
Geological and geochemical characteristics of Cünür volcanogenic massive sulfide mineralization (Kastamonu, Turkey)
No full textÇangaldağ Metamorphic Complex (CMC) in Central Pontides is an accretionary complex consisting of Jurassic units. Mafic, felsic metavolcanics, metamorphic equivalents of deep marine sediments and mafic meta-lava/sill intercalations are the most distinct units of the complex. Cünür Volcanogenic Massive Sulphide (VMS) mineralization is associated with metavolcanic units of CMC. Metavolcanic units in the mineralization area contain volcanic rocks with compositions ranging from sub-alkali basalt to andesite and dacite (50.3 - 74.6 % SiO2). For 0.1 % Cu cut-off grade, 3,372,000 tons (t) of mineral resource with 0.28 % Cu, 0.50 % Zn and 0.19 ppm Au has been estimated. Ore paragenesis of the Cünür mineralization predominantly consists of pyrite, chalcopyrite and sphalerite, and lesser amounts of magnetite. The main ore textures are massive, semi-massive, disseminated, brecciated and fracture fillings. Pyrite-chalcopyrite grading and preserved silicified clasts within the massive ore indicate that mineralization has developed in relation to replacement processes. The most significant grade intercepts reported for the mineralization are 9 %, 9 %, 0.3 %, 3300 ppb and 79 ppm for Cu, Zn, Pb, Au, Ag, respectively. Cünür mineralization has similarities to bimodal-mafic (Noranda type) Cu-Zn dominated VMS deposits.
https://doi.org/10.19111/bulletinofmre.82043
The relationship between seismic quality factor and peak ground acceleration, a case study: M=4.3, 17.01.2015 Eskişehir Earthquake
No full textSeismic wave propagation in subsurface media endures from absorption, which can be evaluated by the seismic quality factor Q (Q-factor). Absorption is frequency-dependent. Lower frequencies are absorbed less, while higher frequencies are absorbed more. Therefore, the Q Factor should be determined in the frequency domain. Q-factor is determined by the slope of the natural logarithm of the output-input signals ratio. Surface waves (Rayleigh and Love waves) are particularly important, as they are the more destructive phases of an earthquake. This study was, focused on the Q-factor computation of the surface waves and demonstrated that the determination of the Q-factor is not affected from the dispersive properties of the surface waves. Data were obtained from surface wave signals of earthquake recorded at Eskişehir Technical University Seismic Network - EstuNet. The obtained Q-factor values represent the average values of the rocks that the waves cross between the input and output stations. Finally, the Q-factor map to the Peak Ground Acceleration (PGA) map using the M=4.3, 17.01.2015 Eskişehir earthquake data was compared. These records show the arrival time of the earthquake from the epicenter to the stations of the seismic waves, and the peak ground acceleration values. In this study, local site effects of EstuNet accelerometric stations have been calculated by using the Standard Spectral Ratio (SSR) method. It is concluded that an inverse relationship exists between the computed Q-factor and measured PGA values. Therefore, the sites where the Q factor is very low should be analyzed in more detail in ground-based earthquake risk assessments. https://doi.org/10.19111/bulletinofmre.84178
Organic geochemical characteristics, depositional environment and hydrocarbon potential of bituminous marls in Bozcahüyük (Seyitömer/Kütahya) Basin
No full textIn this study, the geochemical properties, sedimentation conditions and hydrocarbon potential of the bituminous marls, having quite rich organic carbon content (average 9.27% TOC), composed of gray-green colored, dominant marl lithology with marl-claystone intercalation in the Bozcahüyük (Seyitömer/Kütahya) Basin has been evaluated. In this context, Rock-Eval pyrolysis, Gas Chromatography (GC), Gas Chromatography-Mass Spectrometry (GC-MS) and Modified Fischer Assay (MFA) analyses of the samples taken from the study area were performed and their organic facies have been evaluated. The marls have an excellent source rock characteristics, and include kerogen predominantly as Type I and rarely as Type II. The precipitation of organic matter took place under reducing anoxic redox conditions where oxygen was limited. Analysed samples contain terrestrial phytoclasts and palynomorphs as well as freshwater algae indicating Type-I kerogen such as Botryococcus braunii. Organic geochemical data show that the study area is deposited in the “AB” organic facies continental-marine transition zone. Carbon preference index (CPI), C₂₇, C28 and C29 steran abundance distribution of the samples as well as presence of Gamesaran as a salty environment indicator indicates that the lake enironment has been under marine environment influence from time to time and thereforethe study area have lagoon character. The average of the Tmax values of analysed samples is 432 °C and it was determined that the bituminous marls in the region could not produce conventional petroleum due to their immaturity. However, it has been evaluated that these marls have the potential to produce synthetic petroleum as the kerogen types are dominantly Type-I, TOC and HI contents are high, as well as the analyzed samples have an average of 12.60% (133 L / ton) MFA oil content.
https://doi.org/10.19111/bulletinofmre.79215
Petrographic characteristics of deep marine turbidite sandstones of the Upper Cretaceous Tanjero Formation, Northwestern Sulaimaniyah, Iraq: Implications for provenance and tectonic setting
No full textThis study was carried out to determine the sedimentary provenance of Upper Cretaceous turbidites of Tanjero Formation. The sandstone portion of the unit has been examined based on field and laboratory studies. Seven sections were measured and described in detail on the perfectly cropped out part of the unit at the southern limb of the Sulaimaniyah Syncline. The thickness of the measured sections varies from 120 m to 192 m. The measured sections start from the top of the underlying Shiranish Formation to the syncline axis in the Tanjero Formation. For petrographic analysis sixty-nine representative rock samples were collected. Modal analysis and ternary diagrams point out that, the sandstones are calclithite (litharenite), very fine to medium grained in size consisting of chert, siltstone, mudstone, radiolarian chert and radiolarian mudstone fragments, angular to subangular in shape, very poorly to moderately sorted, transported over short distances and represent submature stage. Grain contact types and high contact index (4.7) indicate moderate to tightly packing, moderate compaction. Transported broken neritic fossil shells, moderately rounded glauconite grains, and undefinable fossils in the altered carbonate rock fragments indicate that the tectonic provenance, lithic recycle category, composed of not only the clastics as interpreted in previous studies derived from Lower Cretaceous Qulqula (radiolarian) Formation which represents deep marine, but also it revealed that a sedimentary formation must also exist in the source area, which is the Lower Cretaceous Balambo Formation.
https://doi.org/10.19111/bulletinofmre.80013
Some criteria used in determining paleoshorelines, examples from Turkey and Rhodes Island
No full textShorelines are important boundaries separating the erosional and the depositional areas. Determining the location of the shorelines in geological time sand how it changes by the time is one of the major problems of geology. The most accurate estimate of the location of the shoreline, which is a dynamic structure, in the period when it was exist is very important in palaeogeographic studies. The determination of coastal changes by the time provides valuable information on active tectonic sand climate, and the relationships between these two. The most basic approach to determine the paleoshoreline is to estimate the geological events on the sea and land sidesand thus to estimate the location of it indirectly. For this purpose, if the physical, chemical and biological conditions of the depositional environments from land to shore and from there to the basin and which land part and how fed this environment can be revealed, the location of the shoreline can be estimated. Incontrast, some field observations provide direct and much more precise data for identifying the paleoshorelines. In this paper, it will be introduced how somerock-boring organisms, wave-cut feature sand coastal sediments can be used to estimate the paleoshorelines based on two examples of Quaternary sediments in Hatay and Rhodes Island along th Mediterranean coastand on some Eocen esediments in the vicinity of Çorum, Central Anatolia. https://doi.org/10.19111/bulletinofmre.71286
Role of the Cretaceous normal faults on the formation of the Eocene (Pontide) fold-thrust belt structures in offshore Akçakoca-Amasra area, Western Black Sea basin, Turkey
No full textThe Western Black Sea basin formed during therifting of the Moesian Platform in Early Cretaceous. The closure of the Neotethys Ocean in the Middle Eocene resulted in the formation of the Pontide fold and thrust belt in northern Turkey. During this study, eight seismic reflection profiles were interpreted to determine the subsurface structural geometry and tectono-stratigraphic evolution of the offshore Akçakoca-Amasra area. The stratigraphy of the study area is determined based on a composite wireline well log of the Akçakoca-1 wildcat well, which was also used to construct a velocity model based onsonic data. We suggest that a major décollement surface was developed during the Eocene Pontide Orogeny. The decollement is located at the limestone clay-shale intraformational transition within the Late Cretaceous (Maastrichtian) - Paleocene Akveren Formation. Normal faults formed during the Cretaceous rifting in the region are located below the décollement surface. They provide tectonic ramps along the décollement surface and allow the decollement to develop ramp-flat thrust fault geometry. A well-developed duplex structure is also present along the seismic lines. The décollement surface serves as the floor thrust of the duplex structure. The roof thrust of the duplex is in the Pliocene Sarıkum formation, dominantly composed of claystone. https://doi.org/10.19111/bulletinofmre.77789
Investigation of the effect of fly ash released from Kütahya thermal power plants by using remote sensing methods
No full textIn order to determine the long-term effect of thermal power plants, the satellite images of Seyitömer and Tunçbilek Thermal Power Plants and their vicinities were analyzed by using the software of ERDAS IMAGINE v9.1 and PCI Geomatica 2017. The normalized difference vegetation index (NDVI) was determined by using red and near-infrared bands of Landsat satellite images, and areas containing vegetation were revealed in the images. In order to obtain the temporal change in the vegetation areas, the relevant image change detection analysis was applied and the one-year and thirty-year temporal change of vegetation cover is for r = 4 km, r = 12 km, r = 50 km. In the remote sensing mapping studies, it was determined that as the diameter of the assessment area increases, the dominant wind loses its effect, and geomorphological conditions are more prominent.
https://doi.org/10.19111/bulletinofmre.94678
Ilk_inv: a Matlab based algorithm for rapid computation of pseudo-3D density contrast distribution by using Bouguer gravity data
No full textThe new generation Matlab-based algorithm provides a rapid estimation of density contrast distribution. The 3D assumption, which is based on the 1D equation, is used. Therefore, the output is called pseudo-3D instead of 3D. The algorithm uses singular value decomposition and the median filter to produce pseudo-3D results. The success of the method is tested by theoretical and field studies. For synthetic studies, single-source models produce reasonable outputs, compared to the true density contrast value. However, the multiple source model shows slight deviations which are ±0.3 g/cm3, with respect to the true density contrast value. The acceptable results are observed for the Bouguer anomaly of the eastern Mediterranean region. The resolution matrix indicates that the inversion process is biased due to the generalised inverse. The algorithm provides a quite different qualitative interpretation perspective to the interpreter.. https://doi.org/10.19111/bulletinofmre.95901
The effect of urban heat island on groundwater located in shallow aquifers of Kütahya city center and shallow geothermal energy potential of the region, Turkey
No full textAs a result of urbanization, natural surfaces are replaced by artificial surfaces that trap heat such as buildings, pavements and asphalt, so residential areas have higher temperature values than rural areas. This effect, defined as the urban heat island, causes an increase not only in air temperature but also in the subsurface and groundwater. Groundwater temperature values were measured during one year in an area approximately 53 km2 consisting of different types of settlement areas to determine the urban heat island effect on the subsurface of Kütahya. As a result of the measurements, urban heat island maps were prepared. It was observed that the groundwater temperature anomalies increased towards the urban/industrial areas. The difference of groundwater temperature in urban/ rural areas reached up to 7 °C by well. This heat energy increasing with the effect of urban heat island can be used in the heating processes of buildings by utilizing systems called “shallow geothermal energy”. For this reason, the heat potential of the alluvial aquifer under Kütahya was calculated. The theoretical heat potential values of the this aquifer range between 1.64 × 1013 kJ K-1 and 5.55 × 1013 kJ K-1 with a mean value of 3.50 × 1013 kJ K-1.It is thought that urban heat island maps and the heat potential calculations of the aquifers may be important parameters for applicability of shallow geothermal systems in the city center of Kütahya. https://doi.org/10.19111/bulletinofmre.82039