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Geothermal reservoir rocks of the Büyük Menderes Graben (Turkey): stratigraphic correlation by a multiproxy approach
This paper focuses on the correlation of two different marble units from an approximately 3,900 m deep geothermal exploration well (GP-1) in western Turkey by petrographical and geochemical data. Future geothermal exploration drilling in that area will benefit from a better (tectono) stratigraphic correlation and a better definition of the reservoir geometry in the basin. It is an innovative approximation in many settings to correctly correlate marble units without clear stratigraphic markers or fossil record, in particular, when sample material is restricted to cuttings.
4/6/2023 8:57:14 AM +00:00
Surface heat flow in Western Anatolia (Turkey) and implications to the thermal structure of the Gediz Graben
Knowledge of heat flow density on the Earth’s surface and subsurface temperature distribution is essential for the interpretation of several processes in the crust such as for the evaluation of the geothermal potential of a region. With this study, we investigate the conductive heat flow distribution in western Anatolia to understand the thermal state and its relationship to regional tectonics in the region. The new heat flow data are collected and combined with previously published data to obtain the new heat flow map of western Anatolia. Analysis of data sets after appropriate corrections yields a better picture of the regional distribution of heat flow within the region.
4/6/2023 8:57:07 AM +00:00
Finite volume modeling of bathymetry and fault-controlled fluid circulation in the Sea of Marmara
: Fluid vents in the Sea of Marmara were discovered and investigated by several studies. In this paper, a numerical model is created for the first time to determine the possible transport mechanism behind those fluid emissions at the seafloor. The finite volume method is used for numerical simulations by implementing a commercial finite volume code, ANSYS-Fluent. The thermal and physical rock properties used in our models are taken from previous studies. Bathymetry, fault-controlled fluid flow velocities, and temperature distribution patterns for the Central Basin and Western High in the Sea of Marmara are simulated and presented.
4/6/2023 8:53:29 AM +00:00
Interpretation of magnetic data using boundary analysis and inversion techniques: a case study from Gölcük/Isparta (Turkey) region
The investigation of magnetic field strength variations over subterranean layers may reveal their locations on Earth’s surface and provide physical and geometrical characteristics. Magnetic studies were carried out around Gölcük caldera lake using proton magnetometers to identify subsurface volcanic structures. The acquired data were inverted using four different edge detection algorithms such as analytic signal, tilt angle, theta map, horizontal gradient. Afterwards, the results were used to determine the locations of the anomalous structures. We also used pseudo-gravity and reduction-to-pole techniques for interpretation.
4/6/2023 8:53:21 AM +00:00
High-resolution temperature and precipitation variability of southwest Anatolia since 1730 CE from Lake Gölcük sedimentary records
Wet periods are evidenced by dark olive green mixed lithology (sandy, clay, and silts) and high values in MS and log(Sr/Ca). On the other hand, dry periods are associated with light olive green clayey mud lithology and high values in log(Ca/K). We relate the wet periods to negative North Atlantic Oscillation (NAO–) and the dry periods to NAO+. Additionally, all wet periods are related with time of low solar activity and dry periods, except Dalton Minimum, are related with periods of high solar activity. Consequently, we suggest that hydroclimatic changes observed in the Lake Gölcük sedimentary records were caused by the influence of largescale atmospheric circulation and solar activity.
4/6/2023 8:53:13 AM +00:00
Reassessment of the age and depositional environment of the Kırkgeçit Formation based on larger benthic foraminifera, NW Elazığ, Eastern Turkey
The middle-upper Eocene Kırkgeçit Formation, the fossil content of which is the subject of this study, is deposited in a back-arc basin controlled by block-faulting. The Kırkgeçit basin is interpreted as being formed under an extensional regime related to convergence between the Anatolian plate in the north and the Arabian plate in the south. The aim of this study is to reassess the age and depositional environment of the Kırkgeçit Formation by using detailed biometric analysis data obtained from the reticulate Nummulites and determinations of other larger benthic foraminifera (LBF) in the unit.
4/6/2023 8:53:04 AM +00:00
The multidisciplinary approaches on facies developments and depositional systems of the Bahçecik travertines, Gümüşhane, NE-Turkey
A carbonate build-up, 12 m thick, was formed with some interruptions, through the middle Pleistocene period. For this study, two travertine sections (F and D) were extensively used to figure out palaeoenvironmental and palaeoclimatic proxies. The main precipitation cycles, separated by palaeosol levels, have been described and interpreted from a sedimentological perspective. The carbonate deposits consist of shrubs, crystalline crust, reed, laminated (micritic), pisoids, oncoids, calcite thin rafts and coated gas bubbles, lithoclasts, and palaeosol levels.
4/6/2023 8:52:54 AM +00:00
Classification of plutonic rock types using thin section images with deep transfer learning
Classification of rocks is one of the basic parts of geological research and is a difficult task due to the heterogeneous properties of rocks. This process is time consuming and requires sufficiently knowledgeable and experienced specialists in the field of petrography. This paper has a novelty in classifying plutonic rock types for the first time using thin section images; and proposes an approach that uses the deep learning method for automatic classification of 12 types of plutonic rocks. Convolutional neural network based DenseNet121, which is one of the deep learning architectures, is used to extract the features from thin section images of rocks; and the classification process is carried out with a single layer fully connected neural network.
4/6/2023 8:52:47 AM +00:00
A numerical approach to verify the reservoir temperature of the Afyon geothermal fields, Turkey
Geothermal energy constitutes an important renewable resource in Turkey that has been extensively utilized for heating buildings, power generation, greenhouse farming and various other industries. One of the most remarkable geothermal locations in Turkey is the low-enthalpy area of Afyon, where five main low-temperature (30–110℃) geothermal fields are exploited. However, further exploration drilling sites have proven inconclusive, casting doubts on the effective presence of high-temperature geothermal systems in the region. Part of the challenge is that the geometry, size and depth of the heat source of the geothermal system is poorly constrained.
4/6/2023 8:52:38 AM +00:00
Basin margin tectonics and morphology as controls of delta type and architecture: examples from the Mio-Pliocene Yalvaç Basin (SW Turkey)
This study describes the sedimentary facies and depositional architectures of Gilbert-type and shoal-water delta deposits developed on opposed margins of the extensional fluvio-lacustrine Yalvaç Basin during the late Cenozoic. The roles of syndepositional tectonism, basin dynamics, and hinterland morphology on the development of different delta types are assessed. This asymmetric trough initially opened as an intramontane molasse basin to the southwest of the Sultandağları massif. Its northern and southern margins are bounded by normal faults, which controlled both tectono-sedimentary evolution of the basin and the surrounding palaeomorphology.
4/6/2023 8:52:19 AM +00:00
Formation age, geochemical characteristics and petrogenesis of syenogranite in Chaihe area, central Daxingan Mountains: Constraints on Late Carboniferous evolution of the Xing’an and Songnen blocks
The tectonic evolutionary history between the Xing’an Block (XB) and Songnen Block (SB) in the eastern Central Asia Orogenic Belt (CAOB) has been hotly debated. In this study, we present a series of new data to provide a better constraint on the magmatic process during plate subduction and its implications for the regional tectonic evolution of XB and SB, even the CAOB. The whole-rock geochemistry and zircon U-Pb chronology of syenogranite in the Chaihe area of the Great Xing’an Range have been carried out. The dating results show that the syenogranite was formed in the Late Carboniferous during the 303.1–316.1 Ma.
4/6/2023 8:52:07 AM +00:00
Tectonic geomorphology of the Yatağan Fault (Muğla, SW Turkey): implications for quantifying vertical slip rates along active normal faults
South Western Anatolia is dominated by E-W and NW-SE trending active faults. The dip-slip Yatağan Fault is one of these active structures that trends in a NW direction for ~30 km. To assess the relative tectonic activity of the Yatağan Fault, two geomorphic segments were defined along the fault: the FS-1 (northern segment) and the FS-2 (southern segment). The vertical slip rate pattern of the fault was analyzed using steepness indexes, chi (χ) plots, and log-log slope area graphs. Results of the analyses indicate that the steepness of the streams draining the footwall reveal increasingly higher values downstream along the fault.
4/6/2023 8:51:54 AM +00:00
Investigation of strain accumulation along Tuzla fault – western Turkey
The Aegean region is one of the most seismically active regions in Turkey and comprises the Hellenic Arc, Greece, and Western Turkey. The Tuzla Fault, which lies between the town of Menderes and Cape Doğanbey, is one of the major seismic threats in western Turkey due to its seismic potential to generate a major earthquake (M 6, near Doğanbey Cape in 1992) and proximity to the city of İzmir which sustained damage due to the earthquake that occurred in the Aegean Sea on October 30th, 2020. In order to estimate strain rates and seismic potential around the Tuzla Fault, five global positioning system (GPS) surveys were carried out between 2009 and 2012.
4/6/2023 8:51:46 AM +00:00
Tectonic implications of the Mw 6.8, 30 October 2020 Kuşadası Gulf earthquake in the frame of active faults of Western Turkey
A Mw 6.8 earthquake struck Western Turkey and Eastern Greece that occurred on October 30, 2020 in Kuşadası Gulf. The earthquake epicentre is located north of Samos Island and the focal mechanism solution shows that a normal fault was reactivated. The main shock and aftershock analysis imply that the large earthquake occurred on a north dipping normal fault which might be the western continuation of the Efes Fault in Western Turkey. We propose that the western continuation of the Efes Fault steps over right somewhere in northeast of Samos Island and continues further west along the northwest margin of the island, in the form of a transfer fault between two segments.
4/6/2023 8:51:35 AM +00:00
Anatomy of October 30, 2020, Samos (Sisam) –Kuşadası earthquake (MW 6.92) and its influence on Aegean earthquake hazard
We investigated rupture geometry, size, and slip distribution of October 30, 2020, Samos (Sisam)–Kuşadası earthquake combining seismographs, GPS measurements, and SAR analysis. Right after the earthquake, we measured 13 additional campaignbased GPS sites to intensify the available GPS network consisting of 10 continuous stations. We combined all available seismographs to have the best possible accuracy for mainshock and aftershock hypocenter locations. We compiled all available seismic profiles and integrated them using high-resolution bathymetry to map seismically active faults.
4/6/2023 8:51:26 AM +00:00
On the drape and level flying aeromagnetic survey modes with terrain effects, and data reduction between arbitrary surfaces
In addition to the physical parameters such as magnetization intensity distribution, the volume and the shape of the magnetized material, directions of the magnetization and the ambient field, the distance between the observation surface and the causative sources significantly affects the shape and the amplitudes of the magnetic anomalies. Aeromagnetic surveys are performed using either a draped surface or a constant elevation plane above sea level. These surveys can easily reconnoiter large territories in a short time. However, the magnetic anomalies may be attenuated resulting in some losses in the data resolution based on the flight height of the survey.
4/6/2023 8:51:18 AM +00:00
Investigation of defective trees using electric resistivity method
The resistivity method in geophysics is used to solve various geological and engineering problems. Recently, this nondestructive method has been used on trees to investigate possible infections within the trunks by scanning resistivity variations. In this study, the electrical resistivity method has been aimed to be applied on various trees in Istanbul, Turkey to test whether the method applies to trees via regular resistivity measurement devices used in geophysics. Firstly, a multi-channel resistivity device, that is designed to automatically take measurements on the ground, is modified to carry out the measurements on trees.
4/6/2023 8:51:08 AM +00:00
Mineralogical and gemmological characteristics of garnets associated with xenoliths within trachyte dome, Hisarlıkaya (Ankara), Central Anatolia, Turkey
Garnet-bearing xenoliths are observed within a trachytic dome extrusion in the Hisarlıkaya region (Ankara). These garnets exhibiting greenish-reddish-dark brown colour and ranging in sizes up to 1 cm were examined in terms of mineralogical, geochemical, and gemmological characteristics. Mineralogical studies indicate that these garnets (And88-93 Grs7-12) are linked to solid solution series, which are dominantly andradite with lower content of grossular. According to major, trace, and rare earth element (REE) analysis
4/6/2023 8:50:58 AM +00:00
Luminescence dating of Quaternary marine terraces from the coastal part of Eastern Black Sea and their tectonic implications for the Eastern Pontides, Turkey
The timing of the deposition of the well-preserved Quaternary marine terraces in the coastal region of northeastern Turkey are crucial in understanding the Quaternary tectonics of the Pontides. The chronology of raised marine terraces between Trabzon and Rize has remained unrevealed because of chronologic limitations. This study aims to establish chronology for the terrace deposits by applying optically stimulated luminescence (OSL) dating methods using single aliquot regenerative dose (SAR) techniques on quartz grains extracted from marine terraces.
4/6/2023 8:50:44 AM +00:00
12th June 2017 offshore Karaburun-Lesvos Island earthquake coseismic deformation analysis using continuous GPS and seismological data
Understanding the tectonic mechanism generated by the earthquakes and faults is possible only if the preseismic, coseismic and postseismic crustal deformation related to the earthquakes is determined properly. By the analysis of continuous GPS (CGPS) coordinate time series, it is possible to estimate the crustal deformation. Besides, accelerometer records at strong motion stations (SMSs) may support the CGPS-based estimates. In this study, CGPS coordinate time series were analyzed in comparison with the accelerometer records for clarifying the coseismic deformation caused by the earthquake occurred in the surrounding of Lesvos fault located in the northern part of Karaburun within the active mechanism that controls the area where the earthquakes occurred during June 2017 on the offshore Karaburun.
4/6/2023 8:50:36 AM +00:00
Alaşehir type - rolling hinge mechanism in the northern margin of Büyük Menderes Graben: Evidence from seismic reflection and recent thermochronological data
Isotopic and thermochronological data were recently obtained from the footwall of the Büyük Menderes detachment ranges from 29.0±1.9 Ma (ZFT) to 1.6±0.2 Ma (Ap U-Th/He), and they can be grouped in three different time intervals. These results are well explained by the Alaşehir type-rolling hinge mechanism, which suggests active rotated initial normal fault during successive normal fault development of the graben formation. This paper suggests that the Alaşehir type-rolling hinge mechanism is applicable to the Büyük Menderes graben by using field observations, published isotopic/thermochronological and subsurface data. It also contributes to the long-lasting discussion about the activation problem on the low-angle normal faults.
4/6/2023 8:50:24 AM +00:00
First report of myalinid bivalves in the Lower Carboniferous of the Hakkari Basin, SE Turkey: paleoecologic and paleogeographic implications
Knowledge of the Late Paleozoic sedimentary history of the northern Gondwana shelf is advanced by new data from the Şort Dere section (Hakkari Basin). Early Carboniferous myalinid bivalves from the Middle East are reported here for the first time. The pre-Permian basement of the Hakkari Basin consists of a Lower Carboniferous sedimentary sequence including the Köprülü and Belek formations. The Köprülü Formation has yielded rich assemblages of vertebrates and invertebrates. Hitherto myalinid bivalves were unknown from this formation.
4/6/2023 8:50:13 AM +00:00
Peritectic assemblage entrainment and mafic–felsic magma interaction in the Late Oligocene–Early Miocene Karadağ Pluton in the Biga Peninsula, northwest Turkey: petrogenesis and geodynamic implications
The Hellenic subduction system governs the entire Aegean region through the creation of a migrating magmatic arc that has existed since the beginning of the Early Cenozoic. The Karadağ Pluton is situated in the NW part of Turkey and represents one of the distinct snapshots of this subduction system during the Late Oligocene-Early Miocene Period.iod. It consists of 2 major lithological units, based on their petrographic and geochemical features, comprising: 1) main plutonic facies (SiO2 < 70 wt.%) that are dominated by hornblende- and biotite-bearing monzogranite, quartz monzonite, and granodiorite, and 2) late-stage more felsic facies (SiO2 > 70 wt.%) that are represented by cordierite-free and cordierite-bearing leucogranites.
4/6/2023 8:49:50 AM +00:00
Dictyoconus aydimi (Gallardo-Garcia and Serra-Kiel, 2016) comb. nov., larger benthic foraminifera from the Middle-Upper Eocene of the Middle East (SE Turkey, Iraq, SW Iran, Oman): New evidence for Arabian Plate faunal provincialism
Rogerella aydimi Gallardo-Garcia and Serra-Kiel was described from the Priabonian Haluf Member of the Aydim Formation, Oman. Based on new finds from the Bartonian Hoya Formation of SE Turkey and the Jahrum Formation of Iran, its taxonomic status is discussed herein. It is concluded that it represents a species of Dictyoconus with a simple subepidermal network (1 rafter, 1 intercalary beam) below a thin epiderm. The stratigraphic range of D. aydimi known thus far is Bartonian-Priabonian or Shallow Benthic Zone 17– 20. The distribution of D. aydimi gives further evidence for a Middle-Late Eocene faunal provincialism of the Arabian Plate (Somalia, Oman, Iran, Iraq, SE Turkey).
4/6/2023 8:49:37 AM +00:00
Stacked debris flows offshore Sakarya Canyon, western Black Sea: morphology, seismic characterization and formation processes
Analysis of ca. 1400 km of multichannel seismic data indicate that the distal part of the Sakarya Canyon within the continental rise is an unstable region with sediment erosion. Fourteen buried debris flows (DB1–DB14), in the stacked form within Plio–Quaternary sediments between 1400 and 1950 m water depth, were observed in the surveyed area. Their run-out distances range from 3.8 to 24.4 km. The largest debris flow DB10 affects ca. 225 km2 surficial area transporting ca. 15 km3 of sediment in S to N direction.
4/6/2023 8:49:27 AM +00:00
Active tectonic stress field analysis in NW Iran-SE Turkey using earthquake focal mechanism data
NW Iran-SE Turkey is a tectonically active zone related to the Arabia-Eurasia convergence, but the active stress state in this zone has not yet been clearly studied. To improve the knowledge of present-day stress state in this region, optimum reduced stress tensor was analysed. For this, a large number of earthquake focal mechanisms (277) were collected. The analyses show most mechanisms exhibit strike-slip to thrust faulting. These data indicate that this region is dominated by an N158° maximum horizontal compressive stress (SHmax) belonging to a transpressional tectonic regime.
4/6/2023 8:49:17 AM +00:00
Time-dependent model for earthquake occurrence and effects of design spectra on structural performance: a case study from the North Anatolian Fault Zone, Turkey
We have investigated the time-dependent seismicity model of the earthquake occurrence on a regional basis through the North Anatolian Fault Zone (NAFZ). To that end, the studied region has been subdivided into 7 seismogenic zones considering the seismotectonic criteria, and then regional time and magnitude predictable (RTIMAP) model has been performed. Intervened times and magnitudes of main shocks produced in each zone have predictive properties defined by the RTIMAP. The probabilities of the next main shocks in 5 decades and the magnitudes of the next events have been estimated using the formation time and magnitude of the past events in the zones.
4/6/2023 8:49:08 AM +00:00
Time frame for future large earthquakes near İstanbul based on east-to-west decelerating failure of the North Anatolian Fault
Large earthquakes that have occurred along the North Anatolian Fault (NAF) were analysed to elaborate the time frame of future large earthquakes near İstanbul. The historical earthquake catalog that was compiled covered 1 nearly complete and 2 fully complete failures of the NAF between 1250 and 2000 AD. These data were used to investigate the space-time systematics of M ≥ 7.0 earthquakes. The catalogue identified an east-to-west decelerating domino-like failure of the NAF. The deceleration starts around the western tip of the 1944 Gerede rupture.
4/6/2023 8:48:58 AM +00:00
Multiple fluid-mineral equilibria approach to constrain the evolution of thermal waters in the Hisaralan geothermal field, Simav Graben, western Turkey
In this study seasonal changes in the geochemical and stable isotope compositions of Hisaralan thermal waters in Simav Graben, western Turkey, were investigated with regards to a variety of mineral-water interactions and mixing processes. The Hisaralan and Emendere geothermal waters, with temperatures of up to 99 °C, were mostly of Na-HCO3 and Ca-HCO3 types. The δ18O and δ2 H values of the Hisaralan waters ranged from –9.32‰ to –8.73‰ and –65.02‰ to –61.10‰, with maximum seasonal differences of 0.3‰ and 1.8‰. The Emendere waters were represented by a more positive range of δ2 H values (–54.95‰ to –54.61‰), while their δ18O compositions (–9.04 to –8.41‰) were very similar to those of the Hisaralan waters.
4/6/2023 8:48:50 AM +00:00
Earthquake history of the Yatağan Fault (Muğla, SW Turkey): implications for regional seismic hazard assessment and paleoseismology in extensional provinces
The southern part of the Western Anatolia Extensional Province is governed by E-W-trending horst-graben systems and NW-SE-oriented active faults. The NW-striking Yatağan Fault is characterised by an almost pure normal sense of motion with a minor dextral strike slip component. Although the settlements within the area have been affected by several earthquake events since ancient times (~2000 BCE), the earthquake potential and history of the Yatağan Fault has remained unknown until a few years ago. Considering the growing dense population within the area, paleoseismology studies were conducted in order to illuminate the historical earthquake activity on the Yatağan Fault.
4/6/2023 8:48:41 AM +00:00