In this study, petrological characteristics of the Early-Middle Eocene Bozanic volcanic rocks resulting from the closure of the Neotethys Ocean in the Central Sakarya region and geodynamic evolution of the Eocene magmatism in the region were investigated. Although previous researchers attained insightful findings about the geodynamic evolution of the region, the age of the post-collisional volcanism, petrological characteristics, and source of the magma remain uncertain. Therefore, volcanic rocks outcropping nearby Saricakaya-Mihalgazi (Eskisehir) are investigated in this study. For that purpose, geological map of the study area was drawn and mineralogical, petrographic, geochemical, and isotopic analyses were performed on rock samples collected from different locations. Bozanic volcanic rocks outcropping as lavas and pyroclastics (agglomerate, lapillistone, and tuff) seem to be derived from four separate volcanic chimneys located in the study area and their composition are typically andesite. According to petrographic data, hypocrystalline porphyritic and microlitic porphyritic are the dominant textures of the rocks. Plagioclase, amphibole, clinopyroxene, and biotite are the main minerals, while sanidine, opaque minerals, chalcedony, calcite, and chlorite can also be observed in small amounts. Geochemically, they show calc-alkaline characteristics and contain medium-high K. Fractional crystallization is the most important process in the development of the rocks. Bozanic volcanic rocks were derived from a lithospheric mantle source that developed in the active continental margin. According to Ar-40/Ar-39 age spectra of the samples, the ranges of 48.13 +/- 0.15-48.78 +/- 0.23 Ma plateau ages were obtained. (Sr-87/Sr-86)i ratios of the rocks range between 0.705404 and 0.705502, while (Nd-143/Nd-144) i ratios range between 0.512570 and 0.512581. Consequently, the age data obtained in this study show that the formation time of the first products of the post-collisional volcanism be as early as the Early Eocene and the presence of those is important in terms of the elucidation of geodynamic evolution of the region.
The first combined mineralogical and geochemical investigation of coal ashes from the Northwest Thrace Coal Basin, Turkey, was performed as a case study. The coal ash samples were obtained at 525 degrees C (group I), 750 degrees C (group II), and 1000 degrees C (group III) ashing temperatures from coal samples from the basin and were studied in terms of their mineralogical and geochemical composition using XRD and ICP-MS methods. The determination of the mineralogical composition was done for all of the groups; the geochemical analysis was carried out only for group II. In accordance with the high SiO2, Fe2O3, CaO, and SO3 content of the ash, quartz (SiO2), hematite (Fe2O3), and anhydrite (CaSO4) are the major crystalline phases for all of the ash groups. The other minerals are muscovite, thenardite, tridymite, calcite, wollastonite, anorthite, cristobalite, gibbsite, ternesite, mullite, nahcolite, and nacrite. High-temperature phases such as mullite, wollastonite, and anorthite were observed at 750 and 1000 degrees C. According to the (Fe2O3+CaO+MgO+K2O+Na2O)/(SiO2+Al2O3+TiO2) ratios varying from 0.19 to 5.65, the ashes are highly prone to slagging. Compared to average values of low-rank coal ashes, the contents of V, Cr, Co, Ni, Zn, As, Rb, Sr, Mo, Cs, W, and U of the ash are higher, whereas the total content of rare earth elements (REEs) (Sigma 163.7 ppm) are lower. Based on upper continental crust normalization, As, Se, Th, and U are enriched in all of the samples. The higher trace element contents in the ashes might be considered as a possible health hazard. The correlation analyses indicated that Ca is associated with anhydrite and As with hematite. The correlation analyses also showed that newly formed Al and Ca silicates may contain the elements such as Ti, K, Na, Cr, Sn, and Pb.
DOI : 10.1007/s12517-017-3006-0
Sayi :10 issue :10
The study area is located in the Central Taurides (southern Turkey), which is bounded by the Kirkkavak fault to the west and Ecemis fault to the east. The sequences are studied in detail based on measured sections composed of the rocks deposited during the Cenomanian-Maastrichtian and located within different tectonic units previously described in the Taurides. The study materials include 217 thin section data from seven Cenomanian-Maastrichtian sequences of outcropping in different parts of the Central Taurides. The sediments deposited during the Cenomanian-Maastrichtian period in the Central Taurides are subdivided into eight units based on their lithological, paleontological, and textural properties. The lower boundaries of the upper Santonian and Campanian are unconformable contacts. The Upper Cretaceous sequence starts with the middle Cenomanian and represents a continuation of the Lower Cretaceous tidal flat and shelf lagoon sequence. Upper Turonian-Coniacian sediments are not observed due to the eustatic sea level drop. The second main transgression period of the Upper Cretaceous platform took place in the Santonian. This unit is represented by limestones composed of wackestones/packstones containing benthic foraminifera and rudist fragments, which are deposited in tidal flats and subtidal environments. The late Campanian starts with a transgression, and the environment transformed transitions into slope facies from inner platform facies, as a result of the thrust of ophiolitic rocks. In the following period, slope front and basin plain environments were dominant due to the increasing slope. Slumped pelagic limestones were deposited on the slope. Planktonic foraminiferal pelagic limestones were unconformably deposited on plaque limestone in the slope front environment depending on the increase in slope gradient and local faulting. As a result of decreasing tectonic activity, the sediments were deposited onto a stable basin plain. They were initially fed from the nearby carbonate platform and then by siliciclastic turbidites derived from the thrusted ophiolitic rocks. In this study, the lithostratigraphic properties of the Cenomanian-Maastrichtian units outcropping in various parts of the Central Taurides are described. The sedimentary deposits described here suggest different basinal conditions in the region.
DOI : 10.1007/s12517-017-3294-4
Sayi :10 issue :22
The occurrence of beach placers, the chromite-rich black sand, and the factors controlling their distribution along the Samandag coasts, SE Turkey, was investigated. One hundred fifty-two surficial (upper 2 to 5 cm) samples of beach sediments from foreshore, backshore, and dune subenvironments; 24 river sediments; 25 samples from ophiolitic source rocks; and ore samples from 4 chromitite mines were collected between the years 2012 and 2015. In addition to hydrogeographic and geomorphological field observations, grain size analysis and total heavy mineral separation and conventional petrographic microscopy studies were carried out. Bimodal, well to moderately well sorted, fine to medium sands were predominant, and on the basis of grain size distribution, at least six sectors could be distinguished by their alongshore fining or coarsening tendencies. Obviously, spatial variations in drainage pattern of fluvial input, wave and current motions, and beach morphology played a crucial role in changing sediment texture. The total heavy mineral (THM) concentrations ranged from 1 to 92 wt% (avg. 40 wt%) in beach sediments and from 3 to 50 wt% in fluvial sediments whereby the bed load of the major and perennial Asi River contained lower THM (9-25 wt%) than its ephemeral tributaries (14-50 wt%) which are in much closer proximity to the source areas. Overall, the THM concentrations in foreshore, backshore, and dune subenvironments tend to decrease in southward direction, except for THM enrichment close to the Asi River mouth. This would reflect rather higher inputs from northerly ephemeral rivers draining the ophiolitic rocks with additionally net longshore sediment transport towards south. The coastal physical processes favoring heavy mineral enrichment such as spatial and temporal variations in swashzone wave dynamics with uprush, backwash, and infiltration effects on the beaches were also observed in the field. The opaque heavy mineral fractions are mostly found in grain size less than 0.25 mm and composed of chromite, magnetite, and ilmenite species with intergrowth textures. Non-opaque heavy mineral fractions were dominated by various species of pyroxenes and amphiboles with lesser amounts of serpentinized olivine. Formation of chromite-rich black sand placers along the Samandag beaches (SE Turkey) and also in river/stream beds resulted from the weathering of mafic-ultramafic rock complexes ("Hatay or Kizildag Ophiolites") and chromite-rich ores of the Amanos Mountains to define the provenance of placers and no considerable input was detected from the Asi River downstream from the Bassaer ophiolites of Syria.
This study addresses the effects of rock characteristics and blasting design parameters on blast-induced vibrations in the Kangal open-pit coal mine, the Tulu open-pit boron mine, and the Kirka open-pit boron mine. In this study, multiple vibration measurements have been conducted, and the related data have been analyzed and evaluated. Several artificial neural network (ANN) and regression models based on the same blasting design parameters, resistivity, and P-wave and S wave velocities of the surrounding rocks have been constructed to estimate the peak particle velocities and the frequencies of related blast-induced vibrations. The data derived from these models and the classical evaluations indicate that ANNs provide more reliable results than the other methods.
DOI : 10.1007/s12517-014-1477-9
Sayi :8 issue :6 Sayfa :4269-4278
Time series obtained from dynamic system must be examined to learn about the variable parameters of a dynamic system. Chaotic time series analysis is very advantageous signal processing methods. These methods are used to determine the nonlinear behaviour of dynamic system. In this study, nonlinear characteristic of Rn-222, which is a radioactive gas, was examined with correlation dimension method. Nonlinear analyses methods are useful for analyses of complex dynamic system behaviour. Correlation dimension analysis is most used chaotic analysis methods. Chaotic time series analyses applications based on 35,136 measurement data from the NurdagA +/- region in Turkey. In this study, the nonlinear analysis techniques are applied to recorded data for the year 2007 and the persistent Rn-222 measurements are received at 15-min times for 12 months in regions. Chaotic correlation dimension analysis results for Rn-222 data was have seen chaotic properties.
DOI : 10.1007/s12517-018-3672-6
Sayi :11 issue :12
This paper presents an experimental and statistical study on the kerf width, used instead of the width of the cut in abrasive waterjet (AWJ) cutting. Pre-dimensioned granitic rocks were sampled for the experimentations designed by using Taguchi orthogonal arrays. The effects of the AWJ operating variables on the kerf width were studied and the rock properties were correlated with the kerf widths. Additionally, predictive models for the kerf widths were developed using multi-variable regression analysis and the developed models were verified through some statistical tests. The results demonstrated that the standoff distance and the traverse speed have significant effects on the kerf widths. The results also showed that water absorption, unit weight, microhardness, the maximum grain size of rock-forming minerals, and mean grain size of the rock have significant correlations with the kerf widths of the tested rocks. Furthermore, the modeling results revealed that the predictive models derived from rock properties, can be successfully used as a practical guideline.
DOI : 10.1007/s12517-013-0984-4
Sayi :7 issue :7 Sayfa :2923-2932
Biochar (BC) is a carbon-rich pyrolyzed material widely used in agriculture for soil amendment in order to enhance crop production and improve soil quality, carbon sequestration (C-sequestration), and mitigation of atmospheric C. Various functions of BC make it valuable; however, the heterogenic properties of BC raise questions regarding its suitability in a particular environment. The present study explored the heterogenic properties of BC with the aim of aligning its uses for soil and the environment. Different types of BC were prepared from feedstocks (FS) of sludge (S), animal waste (AW), and plants originating in the Mediterranean region. Physical and chemical characterization of BC was performed to evaluate its suitability for use in the Mediterranean region with regard to plant nutrient availability. To achieve this, pH, electrical conductivity (EC), and proximate, ultimate, and nutrient analyses were performed. Moreover, scanning electron microscopy (SEM) was also undertaken, and the C-stability of BC was observed using thermogravimetric analysis. Plant FS-derived BC exhibits a high moisture content, volatile matrix, and fixed and total carbon (TC) compared with sludge biochar (SBC) and AW-derived BC. A high calcium carbonate (CaCO3) content was observed in AW-derived BC. Furthermore, the porosity of BC revealed that soil microbes may be sustained inside the porous structure if used for soil amendment. The different FS-oriented BC studied here could potentially be used to amend soil. The AW-derived BC and plant FS-derived BC could be a good source of immediate nutrient release for plant growth in agriculture and C-sequestration, respectively.
DOI : 10.1007/s12517-019-4528-4
Sayi :12 issue :12
Eocene volcanic rocks from the Central Sakarya Zone in the north of the A degrees zmir-Ankara suture zone (IASZ) are predominantly intermediate-acidic lava flows and pyroclastics that crop out with a W-E orientation. The volcanic rocks include Bozani double dagger lavas, agglomerates, A degrees AYdir lavas, and KapA +/- kaya tuffs. The Bozani double dagger lavas contain plagioclase, hornblende, clinopyroxene, and biotite, whereas the A degrees AYdir lavas consist of plagioclase, hornblende, biotite, and quartz. According to the total alkali-silica (TAS) diagram, the Bozani double dagger lavas are mainly composed of andesite and dacite, with one sample of trachyandesite, whereas the A degrees AYdir lavas mainly contain dacite and minor andesite. Bozani double dagger and A degrees AYdir lavas exhibit moderate- to high-K calc-alkaline character. Major oxide and trace element variations suggest the effects of fractional crystallization in the evolution of the volcanic rocks. N-type mid-ocean ridge basalt (MORB) normalized trace element patterns of the lavas exhibit enrichment in large ion lithophile elements (LILEs; K, Rb, Ba, Th) and depletion in high field strength elements (HFSEs; Zr, Ti, Y). In addition, the chondrite-normalized rare earth element (REE) plots of the rocks show moderately enriched and nearly concave-shaped patterns (La-N/Yb-N = 5.4-17.6 for the Bozani double dagger lavas and 6.5-13.1 for the A degrees AYdir lavas), suggesting clinopyroxene (Cpx) and hornblende dominated fractionation. Negative Eu anomalies in the acidic lavas reveal plagioclase fractionation. Some trace element ratios of the lavas demonstrate a subduction signature and crustal contamination in the generation of the parent magma(s). Multi-dimensional tectonic discrimination diagrams suggest that the studied volcanic rocks have developed in a collisional setting.
DOI : 10.1007/s12517-015-1991-4
Sayi :8 issue :12 Sayfa :11239-11260
The main goal of this study is to investigate the effect of the size of the subbasins of a watershed on the hydrologic parameters and their spatial variability in an estimation of the hydrologic parameters and hydrograph of a neighbouring ungauged basin. In this paper, Hydrologic Engineering Center-Hydrologic Modelling System (HEC-HMS), a semi-distributed hydrologic model, is used to calibrate and cross-validate two flood events occurred in 1998 and then validate four other flood events occurred in 1991, 1994, 2002, and 2009 in Gokirmak Basin in Western Black Sea Region, Turkey. The basin is divided into seven different subbasins to investigate the effect of watershed partitioning on calibrated hydrologic parameters of each subbasin using the peak-weighted root mean square error method as an objective function and the hydrograph at the outlet of the whole basin. It is found out that as the geometric magnitudes of the subbasins changed, the calibrated values of the hydrologic parameters of those subbasins changed as well. Then, a neighbouring basin, Kocanaz, is considered as an assumed neighbouring ungauged basin to investigate the effect of watershed partitioning of a gauged basin on the estimation of hydrograph of a neighbouring ungauged basin. Hydrologic parameters and direct runoff hydrograph of assumed ungauged neighbouring basin are estimated from the hydrologic parameters of the HEC-HMS calibration results of Gokirmak. Statistical indicators of the simulation results for each basin partitioning were graded with respect to the boundary values of the simulation outputs to find the best alternative. The grading results show that the simulation results with a single basin gave better representation among all other partitioning except two flood events.
DOI : 10.1007/s12517-017-3132-8
Sayi :10 issue :15
Twelve calcareous nannofossil biozones of Late Oligocene-Late Miocene in Northern Egypt were defined and correlated with their corresponding biozones in Egypt and other parts of the world. These are arranged from the top to base as Zone NN12, Zone NN11, Zone NN10, Zone NN8, Zone NN7, Zone NN6 Zone NN5, NN4, Zone NN3, Zone NN2 Zone NP25 and Zone NP24. In the present study (Boughaz-1 Well), the Late Miocene unconformably overlies the Middle Miocene. This unconformity surface is recognized by the missing of calcareous nannofossil zones NN7 to NN9. While, in North Sinai (Malha-1 Well), the Early/Middle Miocene boundary cannot be recognized, where the Middle Miocene unconformably overlies the topmost Oligocene, and it is defined by the missing calcareous nannofossil zones NN1 to NN4.
Southwestern Turkey experienced a transition from crustal shortening to extension during Late Cenozoic, and evidence of this was recorded in different basin types in the east of Denizli region. The study area comprises a heterogeneous suite of Mesozoic to Recent igneous, metamorphic, and sedimentary rocks. Two main rock groups are distinguished in the area: the basement rocks of pre-Neogene age and the sedimentary cover of Neogene-Quaternary age. In the region, several Late Cenozoic structural basins are filled with terrestrial clastic and volcanic rocks. These basins are different in orientation, geometry, and nature of basin infills. In the studied area, the exposed basal units of the ophiolitic melange correspond to the Lycian Nappe complex. The first sedimentary cover unit, unconformably overlying the nappes, is represented by an E-W-trending basin that is filled with the Oligocene-Lower Miocene shallow marine-terrestrial deposits. The infill of the studied basin consists of the Caykavutu and the Akcay Formations which were deposited during the Late Oligocene and the Early Miocene, respectively. These basins developed as a piggy-back basin along the fault plane on the hanging wall blocks of normal faults. A graben basin (Yeilyuva-Kocaba) started to occur along with NE-SW-trending normal faults which were formed as a result of E-W extensional regime during the Late Miocene. The coarse clastics of the Kzlburun Formation of the Late Miocene age were deposited within an alluvial fan derived from the Elmada Horst in the east of the basin. Whereas the coarse clastics of the Late Miocene basement were accumulated in front of the hanging fault blocks, the fine-grained clastics of the Saraykoy Formation overlie conformably the Kzlburun Formation. The sequence continues with the lacustrine limestones of the Aktepe Formation. Alkaline magmatics of Early-Late Pliocene cut all successions. E-W-trending fault systems formed with the N-S extensional regime affected the basin, and the recent E-W grabens (Curuksu and Acgol Graben) occurred during the Early Pliocene. The recent morphology of the studied area developed under the control of the Aadadere oblique fault zones which are located in the south of the Curuksu Graben.
This paper proposes a new approach to solving the scalability problem in stitching and registration of satellite images. The image stitching process is mostly utilized to capture an image of an entire object, whose parts fall in separate but overlapping mosaics. Due to their high resolutions and huge sizes, the stitching of satellite mosaic images is time- and resource-consuming process. The work presented in this paper proposes a resource- and content-aware, scalable stitching technique. The main idea is based on measuring and assessing the available hardware resources of the machine, on which stitching process runs, and scaling the resolution of the images accordingly. Moreover, preprocessing is not needed, and the adjustment is performed dynamically at run time. The effectiveness of the proposed technique was assessed by partially registering overlapping satellite mosaic images of the island of Cyprus and Lake Van. The scalability tests are performed on varying numbers and sizes of the overlapping LandSat-8 satellite images.
In the eastern part of the Gediz Graben, especially in the Sarigol region, surface deformations that occurred without destructive earthquakes or that continue to occur are frequently observed from the 1969 Alasehir earthquake to the present. Especially in areas where aseismic and tectonic effects are thought to co-exist, such as the Gediz Graben, the general deformation character of the study area cannot be identified precisely from the surface deformations that are determined using the GNSS method as pointwise. However, the general deformation character of the study area can be identified clearly by determining the surface deformations of the study area with the PSInSAR method areally. In this study, in order to determine surface deformations that may be caused by aseismic and/or tectonic effects in the Gediz Graben areally, deformations in the direction of Line of Sight (LOS) were determined by using the persistent scatterer interferometric synthetic aperture radar (PSInSAR) method. In order to determine movements in the LOS direction, TERRASAR-X Stripmap satellite radar images of the German Aerospace Center (DLR) were used. According to the evaluations obtained from the PSInSAR results, it is understood that while there are subsidences in the graben area of the Gediz Graben, there are uplifts in the north and south of the graben. The subsidence values in the graben were obtained to be approximately - 50 mm/year. This result indicates that in addition to creep movement of tectonic origin in the study area, the local soil characteristics and/or seasonal groundwater changes may also increase deformation in areas where deformation occurs.
DOI : 10.1007/s12517-020-05834-5
Sayi :13 issue :17
Most of the costs in open pit quarry operations occur in crushing and grinding processes. Therefore, the management of crushing-grinding processes is very important. Many researchers investigated the effects of pile size distribution and specific charge values occurring as a result of blasting on crusher energy consumptions and provided some cost reductions in the crushers by using suitable explosive. However, these researchers did not sufficiently use discontinuity characteristics of the blasting surface and resistance values of the rock while making these studies. In this study, 15 blasting tests were also realized at two different limestone quarries. Correlations estimating the energy values consumed by primary and secondary crushers were developed by using discontinuity characteristics of blasting surfaces in blast tests, specific charge, and uniaxial compressive strength values of the rock, and compared with energy consumption values measured real timely in the crushers. Very limited error margins were observed in these comparisons. Material exit size at primary crusher must be 15 cm and material exit size at secondary crusher must be 7.5 cm. In addition, primary crusher was of jaw type and secondary crusher was of hammer type.
DOI : 10.1007/s12517-013-1260-3
Sayi :8 issue :2 Sayfa :1133-1144
Thermal, non-thermal, and mineral waters of different hydrogeochemical properties can be found along the same tectonic region on the western side of the Sultandag Massif in Southwestern Turkey. A total of eight representative water samples were taken from the thermal, non-thermal, and mineral waters in the study area. The waters in the study area are divided into 3 different facies: (i) Ca-Mg-HCO3, (ii) Ca-Mg-HCO3-SO4, and (iii) Ca-Mg-SO4-(HCO3). Major hydrogeochemical processes that control the chemical composition of waters in the region are carbonate and silicate weathering. Thermal and mineral waters in the region have high dissolved ion content due to intense water-rock interaction. The surface temperatures of geothermal waters were found to be between 22.1 and 33.9 degrees C, and reservoir temperatures, which ranged between 30 and 84 degrees C, were calculated according to geothermometer evaluation. The heat source of the thermal waters in the study area is thought to be related to the geothermal gradient. Using the Curie point depth (D-CPD: 17 km) and Curie point depth temperature (T-CPD: 580 degrees C) data, the geothermal gradient and heat flow in the region were determined to be 34.12 degrees C/km and 71.65 mW/m(2), respectively. Based on these data, it is determined that the waters come from a depth of 1.50-2.47 km.
DOI : 10.1007/s12517-020-05861-2
Sayi :13 issue :17
In this study, the classification of the risk of new safety slip of the pedestrians in natural stone floor covering when barefoot and walking with shoes. A total of 15 types of natural stones were categorized according to and subjected to their geological, mineralogical-petrographic, chemical, physical, and mechanical characterization tests. Coefficients of friction (COF) have been found by the natural stone formed four surface processing techniques (SPTs), three environmental conditions, ramp and pendulum test device, and DIN EN 51097, DIN EN 51130, and TS EN 14231 standards. The new slip safety risk scale is determined by the K-means method considering the wet (WE), dry (DE), and lubricated (LE) environmental conditions and the applied SPT of the parameters affecting the COF values of natural stones. With the data obtained from the tests, the slip safety risk scale of the COF of natural stones was determined by the statistical K-means clustering method. According to statistical results, natural stones have been classified according to three slip test depending on their COF values.
DOI : 10.1007/s12517-018-4173-3
Sayi :11 issue :24
Iron oxide mineralizations in the eastern part of the Pontides (NE Turkey) are hosted in the skarn environments which are the Pontide paleomagmatic arc. These mineralizations always occur in the contacts between granitoid and limestone. Magnetites are hosted in carbonate rocks and generally formed during garnet-magnetite-epidote-quartz phase. Magnetites have high Co (15.8-43.4 ppm for the Kopuz, 11-12.5 ppm for the Erikar, and 3.8-1266.7 ppm for the Karada) concentrations suggesting that the sulfide decreased from the early to the late phases in the iron skarn mineralization forming systems. The Co/Ni ratios in the magnetites (0.12 to 35.38 for Karada, 2.19 to 13.53 for the Kopuz, and 2.39 to 5.21 for the Erikar) show the hydrothermal effect on the magmatic source in iron skarns in the study area. Thus, variable Co/Ni ratios reflect interactions between the magma with the host rock during successive alteration stages. Magnetites in this study have Sc-Nb-Mg-Ti depletions and Ta enrichment. In this study, high Co, Ti, and V contents in magnetites suggest the high temperature (300-500 degrees C) and low integral O-2. The V contents of the magnetite in the Karada increase with the decreasing oxygen fugacity of fluid(s) forming magnetites, whereas the V contents of the magnetites in the Kopuz and Erikar decrease with increasing oxygen fugacity of fluid(s) forming magnetites. Element patterns and Ni/Cr ratio (<1) of the magnetite are geochemically similar to those of magnetite in Fe-skarn deposits and partly magmatic accessory magnetite of I-type granites. As a result, the Co, Ni, V, and Ti elements of the magnetite have played an important role in the discriminating and interpreting of skarn mineralizations in the eastern Pontides and support a calcic skarn origin with studies of the mineralization geology.
The geothermal energy does not pollute the environment and atmosphere during production and consumption. Akarcay basin (Afyonkarahisar) has significant geothermal potential in Turkey. Geothermal waters in the basin are used for tourism, residential heating, greenhouse, and balneological applications. Hydrothermal alteration zones are essential indicators for the exploration of geothermal fields. In the feasibility studies of geothermal exploratory studies, outcrops of alteration contribute significantly to the exploration studies in investigation of target areas. The use of remote-sensing techniques in the detection of hydrothermal alteration minerals spread over large areas enables large areas to be evaluated holistically, saving both time and economically and achieving effective results. In this study, the Crosta and Spectral Angle Mapping (SAM) techniques were applied to determine the hydrothermal alteration zones by using ASTER satellite data. In this context, samples from hydrothermal alteration zones were collected from the study area. The mineralogical compositions of studied samples were determined by using X-ray diffraction (XRD) method. Alteration zones were also distinguished in similar locations in mapping techniques and XRD method. The results were combined, and the final alteration zones were formed. The alteration zones masked with volcanic and metamorphic rocks in order to be a geothermal indicator of hydrothermal alterations. The existing alteration zones are almost on the existing geothermal fields. As a result of the study, alteration zones were proposed different from the existing alteration zones. It is expected that these zones will be a reference in future geothermal explorations.
DOI : 10.1007/s12517-020-06083-2
Sayi :13 issue :21
The mineralogical properties of the Precambrian-early Paleozoic series have been investigated in the Southeast Anatolian Autochthon (SEAA) and are represented by generally clayey siliciclastic and rarer volcanogenic rocks. These include basalt, andesite, and volcanic sandstones of the Precambrian period; siliceous sandstone, dolomite, shale, and siltstone of the Cambrian period; and sandy dolomite, shale, siltstone, sandstone, and limestone with red Fe nodules of the Lower-Upper Ordovician period. The rock-forming minerals determined in order of abundance are feldspar, pyroxene, quartz, and olivine in the Precambrian unit; quartz, moganite, calcite, dolomite, feldspar, and phyllosilicates (illite, chlorite, mixed-layered illite-smectite/I-S, smectite) in the Cambrian units; and phyllosilicates (kaolinite, illite, chlorite, I-S, mixed-layered chlorite-vermiculite/C-V, smectite), quartz, feldspar, calcite, dolomite, moganite, and goethite in the Lower-Upper Ordovician units. Short prismatic and partly radiating moganites discovered in the early Paleozoic sediments in Turkey are present between euhedral and coarse-grained quartz and feldspar in the sandstones. Thin platy illites have undergone a transition that introduces a fibrous/thread-like mixed-layer I-S through their edges. The rhombohedral dolomites have dissolution traces associated with siliceous balls, long thin filament-shaped illites, and acicular-radial chlorites. Illites usually show coarse and tiny plates parallel to each other and partly radiating flakes, and chamosite-type chlorites form thick plates in the siliciclastics. Kaolinites consist of typical pseudohexagonal sheets with parallel or accordion-like booklets in the siltstones. The Kubler index indicates low- to high-grade diagenesis to low-grade diagenesis, signifying that the location partially differs from the other units of the SEAA and Taurus Belt. In addition, Paleozoic rocks reflect no maturation characteristics with respect to the petroleum system.
DOI : 10.1007/s12517-015-2006-1
Sayi :8 issue :12 Sayfa :11261-11278
A good knowledge of the mechanism of slope failure in open-cast mines can be understood by evaluating the intrinsic and extrinsic factors and their interactions in causing slope instability, and by gathering displacement information from periodical monitoring. Surface deformations, caused by mining activities at mine sites, are conventionally measured by using survey instruments such as levels, theodolites, total stations, GPS receivers, and photogrammetric cameras. However, conventional long-term monitoring techniques are insufficient due to unfavorable factors such as topographic structure and flora of the observation, urbanization rate, and time delays in obtaining results. Due to this fact that the Interferometric Synthetic Aperture Radar (InSAR) technique has become prominent in recent years as a method that uses satellite data to enable the detection of surface deformations and movements especially in very large areas. In this study, the mechanism of slope failure accurately detected by way of associating mechanical and physical information of the slopes with time-dependent deformation behavior (time series analysis) by periodically monitoring of displacements at the benches of a lignite open pit that experienced interruptions of production due to slope failures. Mining area has been periodically monitored by InSAR and data consisting of the time-dependent behavior of the deformations were correlated with the mechanical and physical property data that were obtained from back analysis of slope failure using finite elements method (FEM) approximation. In this context, a dynamic method was proposed that can predict the failure risk of the slopes at the site before the critical displacement values are not reached.
Poor management, low vegetation cover, and severe evasion are undermining the stability and sustainability of lands. In this study, modified Mediterranean Desertification and Land Use (MEDALUS) method was used to identify environmentally sensitive areas (ESA) to desertification in Tigris Basin, Turkey. Soil samplings (0-20 cm) and field observations were conducted within 3.752 km(2) land. Biophysical and anthropogenic parameters of sampling locations have been integrated and processed by geographic information systems obtaining soil, climate, vegetation, and management quality indexes. Additional six parameters for soil quality and one for management quality were used to adopt MEDALUS to the context of Tigris Basin. The weights for parameters and indicators were calculated using analytical hierarchy process (AHP). Tigris Basin was classified into one fragile and two critical areas using original method. whereas one fragile and three critical classes were defined with the modified method. In the original method, fragile areas represented 5.65% and low-degree critical areas 24.49% and moderate critical areas 69.86% of the study area, which are needed to be monitored for severe land degradation. Modifying MEDALUS allowed to define highly critical areas (51.41%) which have not been detected in the original method. The critical areas are primarily used for field crops with extensive tillage, medium degree of plant cover, low drought resistance, and erosion along with low management quality due to the lack of required environmental protection. The results revealed that adaptation of new parameters and weighting in MEDALUS improved the ability of classifying ESAs for a regional scale to desertification.
DOI : 10.1007/s12517-018-3813-y
Sayi :11 issue :17
Karapinar, located in the middle of Konya Closed Basin in Turkey, is a district that is agriculturally and economically significant. The natural life and agricultural future of the district are threatened by the gradual reduction of underground water resources, application of intensive agricultural activities that are unable to account for climate characteristics, and climate change effects. When the geological structure of the district is added to all these parameters, environmental problems such as land subsidence and sinkhole formation occur in the district. This study presents the results of a research project evaluating sinkhole susceptibility using remote sensing and geographic information systems in the district of Karapinar in Konya, Turkey. In addition, the importance of adding deformation map that was produced using InSAR analyses as a factor in the sinkhole susceptibility mapping was emphasized. A sinkhole susceptibility map was produced to determine the potential sinkhole areas based on expert opinions by applying the analytical hierarchy process approach and considering a selection of 13 factors. The map produced was in high agreement with the recent sinkholes in the district. The results of this study showed that the analytical hierarchy process can be a useful approach for susceptibility assessments when data on the main controlling factors have sufficient accuracy and spatial coverage. In addition, the map presented apparent sinkhole susceptibility in the area in accordance with the selected parameters and informed decision makers regarding natural hazard risks in Karapinar.
DOI : 10.1007/s12517-020-05841-6
Sayi :13 issue :17
Thermal barrier coatings (TBCs) are extensively used to protect critical components such as aircraft turbines to provide thermal insulation at elevated temperatures. At high operating temperatures, damage mechanisms such as oxidation and hot corrosion result in spallation of TBC system. The spallation occurs due to the phase transformation during penetration of hot corrosion salts to top coat. YSZ is mainly used as top coat material for TBC systems. However, YSZ cannot be used in temperature higher than 1000 A degrees C. More superior efficiency of gas turbine engines will demand a new generation materials for TBC systems. Nowadays, rare earth zirconates, Gd2Zr2O7, La2Zr2O7, YSZ/Gd2Zr2O7, and YSZ/La2Zr2O7 used as ceramic top coat materials in gas turbine engine components owing to their superior thermal isolation and hot corrosion resistance properties. In this study, hot corrosion mechanism, rare earth zirconates, and their properties as well as their hot corrosion behavior in TBCs were investigated based on literature studies.
This study focuses on the vibration effects of both metro (subway) tunnel construction and metro-operating traffic on existing buildings. To that end, a four-story reinforced concrete building located between two metro tunnels of uskudar-umraniye-cekmekoy Metro Project (UUCMP) was monitored both during the tunneling stages of construction and after the metro traffic started. Acceleration records were gathered from the building during the pass of two tunnel boring machines (TBMs) just below the building. Both magnitudes of the acceleration and the building frequencies were investigated for the active and passive stages of TBMs. The operation of the first TBM caused an obvious increase in the magnitudes of the vibration measured from the building, while the operation of the second TBM did not show any meaningful increase in the vibration magnitudes. These data were evaluated together with the characteristics of the soil between the building and the metro tunnels. After the completion of the construction, the metro lines were put into service. In this stage, acceleration measurements were gathered to reveal the effects of metro traffic on the studied building as well. It was seen that the metro traffic increased the magnitude of the vibration on the building. Firstly, this study underlined the importance of the soil profile between the tunnels and the studied structures for the propagation of TBM-induced vibrations. Secondly, in both tunnels, daily metro traffic caused higher magnitudes of vibration on the studied building compared with those of the TBMs. In conclusion, TBM vibration data can be used for detecting and determining critical structures in order to take precautions during the construction stage before the metro lines are put into service.
DOI : 10.1007/s12517-020-05456-x
Sayi :13 issue :11
The correct measurement of velocities in rivers is important for the true determination of discharge, erosion, scouring, and sediment transport processes. With the goal of increased accuracy, the use of acoustic Doppler velocimeters (ADVs) is increasing in hydrological measurements in rivers, lakes, and laboratories. ADVs are extensively used in the USA. ADVs have advantages when compared with classical measurement devices; however, one must be careful while using an ADV because their sampling approach creates a large number of extreme values by sending signals into the flow, measuring the velocities of particles moving with the water and assuming that these particles move with same velocity as the water. To calculate unbiased statistical properties, outliers must be removed from the time series. This study explains the methods used to filter velocity time series collected with ADVs and investigates the effects of these filters on the statistical characteristics of the filtered time series.
DOI : 10.1007/s12517-012-0523-8
Sayi :6 issue :7 Sayfa :2691-2697
Dynamic soil amplification factor (DAF) defining which ratio earthquake acceleration will reach the soil surface by changing is one of the most important factors in seismic risk studies. When computing the value of DAF at a point without a strong motion station, peak horizontal acceleration values (PGA) at the bedrock and soil transfer function are needed. PGA value at the bedrock can be obtained by using either real seismic records or the earthquake scenario. However, the soil transfer function (soil transfer function) can be computed observationally and theoretically. Observational soil transfer function is defined by microtremor horizontal/vertical spectral ratio. In case of theoretical computation, the density belonging to the soil layers between the bedrock and the soil surface is used together with the change of P-S wave rates with the depth and the damping factor. In this study, the dynamic amplification factor (DAF) has been computed and mapped for 57 points by using observational soil transfer functions obtained by microtremor horizontal/vertical spectral ratio as well as the earthquake scenario at a new city center located within the metropolitan area of Izmir. Also, theoretical soil transfer function at 1 point was obtained through spatial autocorrelation method (SPAC) study and determined to be compatible with observational result. It was observed that both peak period values are higher than 1 s and DAF values are higher than 2 throughout the area. Also, according to the soil profile obtained from the SPAC study, S wave rate changes up to a depth of 1300 m showing that acoustic impedance differences may occur in the frequencies and the magnitudes of the earthquake waves. The fact that peak period values obtained from microtremor studies are higher than 2 s supports this result. This means that acoustic impedance differences likely to occur in these depths should also be taken into consideration while computing the dynamic amplification factor.
DOI : 10.1007/s12517-015-1881-9
Sayi :8 issue :11 Sayfa :10093-10104
Recently, the rate of urbanisation has accelerated due to increasing population density which causes unexpected environmental disturbances and problems. One of the major problems encountered to date is the change in the land use/cover (LULC) structure. Increasing the impervious surface cover has changed microclimatic properties of urbanised areas by altering their thermal characteristics. One of the most important problems facing urban planning today is the phenomena known as the urban heat island (UHI), which is largely due to the changing the character of LULC. In this study, to create a national picture of the UHI structure in Turkey, seven cities, namely Istanbul, Bursa, Ankara, Izmir, Gaziantep, Erzurum and Trabzon, each located in different climatic regions of Turkey, were investigated. The Gaussian fitting technique was applied to characterise the UHI effect in the seven cities in the study. An original contribution of the current study was that the rural reference temperature surface was automatically determined by a proposed algorithm including the automatic masking of input data, as well as the application of iterative Gaussian low-pass filtering during the fitting procedure. Within this context, the daytime and nighttime surface urban heat island (SUHI) effect was modelled and temporally analysed from 1984 to 2011 for all the sub-regions using remote sensing techniques. Furthermore, atmospheric UHI was also investigated using the mobile transect method. The findings from this study suggest that UHI is a major environmental problem in urbanised areas, both atmospheric UHI and SUHI were detected in all cities in the study area, and this problem was found to have rapidly increased from 1984 to 2011. Finally, as inferred from the multiple regression results, it can be concluded that the UHI problem in Turkey might have resulted from the altered LULC structure, as well as anthropogenic pressure on and interference in city planning geometries.
To develop relatively simple equations for design of a reinforced pavement design model, tests were conducted. Firstly, the effects of vertical spacing of reinforcement layers and depth of the reinforced zone were investigated by using different types of geosynthetic materials. The number of the reinforcement layers was also varied to see how these material parameters influenced the results. The comprehensive results from laboratory model tests supported on a woven geotextile and different geogrids were presented. The results were compared to each other. Based on model tests, different reinforcement types showed different behaviors for different numbers of reinforcement layers and different vertical spacing of the reinforcement layers. Additionally, it was seen that the improvement obtained by reinforcing the subgrade is different for low settlement ratio values and large settlement values for different vertical spacing values. Then, new simple estimation formulas were determined for bearing ratio by regression analyses for different types of reinforcement materials.
DOI : 10.1007/s12517-018-3664-6
Sayi :11 issue :13
This study proposes a new method to obtain the lateral response of pile groups by incorporating the pile group effect in layered soils. When a pile is loaded laterally, it creates a zone of influence in the direction of loading. In a pile group, each pile placed in the influence zone of prior piles is exposed to extra loads due to the load transfers from other piles. This mechanism results in a group effect which causes each pile in the group to have a different deflection curve compared to that of an identical isolated single pile under the same load. This study starts with a mathematical approach to model the interaction of two piles and then extends it to pile groups. The governing differential equation of a pile deflection problem is modified to take the pile-soil-pile interaction into account and solved analytically for each pile while the soil parameters and displacement fields around each pile are obtained numerically using the finite difference method written in Fortran language. The model captures the additional pile deflections induced by the group effects in pile groups and the results match well with the results of the existing methods, especially the finite element method.