Türkiye Jeoloji Bülteni

Abstract: With each passing day, industrialization, the use of fossil fuels, uncontrolled agriculture and similarhuman activities are increasing. As a results of these activities, the nature is impacted by a number of changesand anthropogenic pollution. In this study, drilling core samples from the Izmit Bay (IZC-01) in the Sea ofMarmara, Surmene (SC-01) and Hopa (HC-01) coasts in the Black Sea have been investigated with lithological,sedimentological, paleontological and geochemical perspectives. The concentrations of heavy metals as Ba, As, Pb,Cd, Cr, Ni, Ti and Zn were considered from total of 45 samples which are covering 15 samples from each three cores.PLI (Pollution load index) values are calculated by using the results of As, Ba, Pb, Cr, Ni, and Zn elements, standout 3.255 for the Gulf of Izmit, 2,195 and 1,706 for Surmene and Hopa in respectively. PLI values indicate acceptedlevel of pollution above for the Gulf of Izmit and despite being dirty Sürmene and Hopa relatively less polluted. Inaddition, EF values indicate a significant enrichment of the As, Ni and Cr and moderate enrichment of Pb and Znelements at Izmit Gulf. In locations Hopa and Sürmene; As, Ba and Cr elements showing insufficient enrichment and Ni, Pb and Zn was observed a significant enrichment. Besides, pollution related gypsum crystallization isalso remarkable for Maramara core. The abundance and diversity of paleontological records in the cores are alsocompatible in line with the decreasing and increasing rate of pollution. Towards the deepest part of the all 3 cores, areduction in the concentrations of elements such as Pb, Zn, Cr and As is seen. Radiocarbon dates obtained from theshells of these reduction levels are mesured in Sürmene 420±55 (BP) and Hopa 500±50 (BP). In addition, results ofthe other previous studies based on sedimentation rate and these ages are compatible. These specified age rangeswere compared with opinions in the literature which are related to the beginning of Anthropocene and because ofthe overlaping, these clearly observed levels have been interpreted as the limit of the possible Anthropocene time.

Abstract: One of the prominent examples of the surface deformations that have been formed without destructiveearthquake failure since last 10-20 years in the west Anatolian extensional province, observed in Bolvadin settlementarea located at the middle part of the Afyon-Akşehir Graben. In this area, some linear surface deformations thatstarts on the southwestern side of the town and can be followed until the northwestern side have been observed sincelast 4 years. During the field studies in Bolvadin area, progressive surface deformations such as surface faults andearth fissures whose length varies between 300 meters and 2 kilometers and strike varies between N15°E and N70°Eare mapped. The northernmost one of the surface deformations mapped in settlement area of Bolvadin have thecharacteristics of the southwestern continuation of Bolvadin Fault. Besides this, qeologic and morphological analysisindicate that the southeastern block is a down-dropped block and vertical displacements along the deformation zoneare varies between 10-40 cm. According to geodesic data, measured rates of vertical offset in the Bolvadin is 7.1 cm/year. In order to find out the effect of active tectonism on formation of surface deformations, further trench basedpalaeosismological studies are necessary.

Abstract: The Miocene-Pliocene lacustrine units comprises bituminous shale, coal seam, conglomerate, siltstone,sandstone and claystone were deposited in a graben developed along the Eskişehir Fault Zone at the east ofEskişehir. The geological, mineralogical and geochemical analyses were performed on samples obtained fromES4 and ES7 core drilling holes at the Alpu coal basin. Abundant smectite associated with kaolinite, illite, quartz,feldspar, dolomite, siderite, accessory amphibole, gypsum, alunite and pyrite. The muscovite, chlorite, feldspar,serpantine crystals and their groundmass are partly to completely argillized in host rocks. Micromorphologically,development of smectite flakes and platy illite crystals on relicts of feldspar suggest dissolution and a precipitationmechanism under alkaline micro-environmental conditions during diagenesis. Enrichment of light rare-earthelements relative to middle rare-earth elements and heavy rare-earth elements and positive Eu anomalies reflectalteration of feldspar. Alteration of feldspar, biotite and serpentine resulted in the concentration of Al, F, and Mg ina stagnant envrionment and precipitation smectite and in an alkaline environment. The low to moderate Ni/Co andhigh V/(V+Ni) ratios are indicative of oxic to dysoxic and anoxic to dysoxic conditions, respectively. TiO2/Ni andSiO2 versus (Al2O3+K2O+Na2O) discrimination diagram show that weathered samples is indicative of formationfrom the locally basic igneous rocks and alteration formed predominantly via sedimentation process under arid andsemiarid conditions and formation of clay minerals.

Abstract: Computations of x- and y-components of the horizontal derivatives (gradients) from an anomaly grid (withx- and y-axes directed east and north, respectively) still take an important place in potential field data-processingtechniques. These techniques may successfully bring out some significant subtle details that are masked in theanomaly maps. Particularly abrupt lateral changes in densities and magnetizations effectively aid geological mappingand these changes may be traced by some derivative-based techniques without specifying any prior informationabout the nature of the potential field source bodies. Hence derivative-based techniques are regularly used inthe visual interpretation of potential field anomalies. It is well known that computation of horizontal derivativescan be performed through either fast Fourier transform (i.e. in wave number domain) or simple finite-differenceequations (i.e. in space domain) to outline the geological source boundaries (edges). Numerous studies includingthe use of either one have been recorded in the literature so far. In this study, comprehensive comparisons of thesolutions obtained from those techniques have been made using both synthetically produced and real gravity datasets. Synthetic applications have been performed using both noise-free and noisy gravity data sets for two differentdepth-to-source scenarios. Thus not only the signal-to-noise ratios but also the depth-to-source conditions have beenanalyzed to test the performance of those approaches. Additionally, a real data experiment has been achieved usingregional Bouguer gravity anomalies from a portion of a well-known geological setting, the Aegean Graben System(Western Anatolia, Turkey). 

Abstract: Digital elevation models have been evolved in decades, their resolution and accuracy have improvedvividly. Geological, structural and geomorphological benefits of those high-quality digital elevation models enhancedthe quality of the research and engineering and unfold the visibility of the data. Modern techniques such as laserscanners provide a quantum leap on digital modelling, however the cost of those methods limits their widespreadusage. Improvements in stereo-photogrammetry did not decelerate. On the contrary, the evolution of Structure fromMotion–Multi-view stereo-photogrammetry (SfM-MVS) method is accelerated by the continuous developments indigital photography and computer vision technologies. We have used a lightweight drone to acquire digital aerialphotographs of an open mine pit for an ultimate purpose of modelling the terrain using SfM-MVS procedure. Wehave been able to derive a high resolution (0.3 m/pixel) DEM and a very high resolution (0.04 m/pixel) orthorectifiedaerial image. Both datasets are representing the topography with high sample point densities. Elevation model datasethas been compared with the regular topographic point measurements of the mine pit and the accuracy of the aeriallyderived model have been investigated. Sources of modelling errors, the effect of temporal physical changes in theterrain, effect and importance of geo-referencing have been discussed in detail. SfM-MVS is a cost-effective, rapidand promising technique for digital mapping, modelling and monitoring in various spatial scales of Geology.

Abstract: Güre geothermal field is located in NW Anatolia within the boundaries of Balıkesir. This study attemptsto determine the geologic and hydrogeochemical characteristics of the field and close surroundings and theircorrelation with active tectonism. The basement of Güre geothermal field is rocks of the Paleozoic-age KazdağGroup. Above the basement, the Triassic-age Karakaya Formation lies above an unconformity. The CretaceousÇetmi melange tectonically overlies this basement. The Upper Oligocene-Lower Miocene Hallaçlar volcanics andOligo-Miocene granodiorites were emplaced by cutting all older units. Quaternary alluvium unconformably overliesall units in the study area. The Güre geothermal field located on the east section of the Edremit Fault Zone, markedas an active fault on the Active Fault Map of Turkey, is controlled by a nearly ENE-WSW oriented, south-dippingnormal fault. In the instrumental period from September 2013 to August 2014, nearly 12 earthquakes occurred inthis region and close surroundings with M=3.0 or more. Geothermal water from four hot-water wells in the Güregoethermal field had monitoring studies performed in 12 different periods from 21.09.2013-16.08.2014. Physicochemical measurements and experimental studies of water from Güre geothermal field were compared simultaneousto earthquakes in the region. Before and after earthquakes changes were observed in these thermal waters, especially T0C, pH and EC values. Additionally chemical analysis of the water identified increases or reductions in manyelemental levels, especially Cl-, Na+ and SO4-2. It was concluded that these variations were directly related to theactive tectonic regime in the region.