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The development of carbon capture and storage techniques has become essential to reduce and mitigating CO2 emissions to the atmosphere. CarbFix1 and CarbFix2 projects carried out in Iceland demonstrated that the emissions of waste CO2 gas from geothermal power plants can be captured and mixed with the effluent geofluid and subsequently injected back into the geothermal reservoir. This experience gained in the CarbFix projects expanded into other geothermal fields around Europe, and one of the demonstration sites is the geothermal field in Turkey, Kızıldere. This paper focuses on the results of an updated study on early field evaluations with reactive transport simulations. In the new three-dimensional numerical model, the geological formations and fault zones were updated according to the well-logs data. Based on the tracer tests performed in the field, the anisotropic permeabilities between the wells were evaluated and imposed into the model. Geofluid chemistry, mineral components, and the volume fractions used as input in the simulations are modified depending on the performed laboratory experiments on the metamorphic schists taken from the geothermal site (i.e. X-ray diffraction (XRD), energy dispersive X-ray (EDX), scanning-electron microscope (SEM), and batch reactor tests). Different thermodynamic databases such as Lawrance Livermore National Laboratory (LLNL) and Thermoddem databases were tested using PHREEQC and TOUGHREACT programs for consistency with experiments. The thermodynamic conditions and the geofluid-rock-CO2 interactions prevent the mineralization of CO2 in the reservoir. This outcome differs from CarbFix projects in terms of the carbonization process, but the CO2 injection is still reliable with solubility-trapping in a geothermal reservoir to partially mitigate the emission. Roughly, 200 kt of CO2 in 10 years can be safely injected into the geothermal reservoir. According to the new analysis, the ratio of magnesium, sodium, and potassium varies in solid solution series of feldspars and clay minerals as albite end-member and montmorillonite/illite end-members, respectively. The evaluations of solid solution reactions are relatively limited in the law of mass action approach used by PHREEQC and TOUGHREACT. [ABSTRACT FROM AUTHOR]

Modal analysis of sandstones for conglomerate rich marine basins is useful for investigating the provenance types surrounded by plate tectonics. Different kinds of siliciclastic rocks are important indicators for defining the paleogeography and geotectonic conditions of the sedimentary basin by provenance analysis. This paper, which focuses on the petrography and provenance of conglomerate rich turbidite systems, is one of the rarest studies on the sedimentary characteristics in the scientific literature. In this context, the study was carried out in the western part of the Elazığ Basin. The Middle Eocene-Oligocene basin infill called the Kırkgeçit Formation is characterised by the conglomerate rich submarine channel deposits and coarse-grained turbidite sandstones. Petrographically, the coarse-grained sandstones of the Kırkgeçit Formation are composed of litharenite and rarely feldspathic litharenite, lithic arkose and rock fragments. Mostly the components are derived from volcanic and plutonic rocks of the Elazığ Magmatites. Fossils and fossil fragments are transported from the shallow part of the western Elazığ Basin. The components transported from metamorphic rock fragments, which are rarely observed in the sandstone samples, are composed of recrystallized limestones and derived from Keban Metamorphites in the northern part of the basin. The provenance studies and petrographic analyses indicated that the conglomerate rich channels and coarse-grained sediments of turbidite sandstones in the Kırkgeçit Formation were plotted mostly to the recycled orogenic and undissected arc type source rocks. Therefore, this type of source rocks has been reflected as a back-arc basin deposit during Middle-Upper Eocene. The geotectonic evolution of the western Elazığ Basin has also supported this remark. [ABSTRACT FROM AUTHOR]

This paper aimed to determine the grey water footprint (GWF) of geothermal water resources and to investigate the effect of biochar adsorption on grey water footprint in Southeastern Turkey. In this paper, GWF has been calculated in terms of iron (Fe), arsenic (As), manganese (Mn), boron (B), and chrome (Cr) concentrations for fifteen observation geothermal resources located in Southeastern Anatolia Region. In this study, a new approach based on the GWF was developed in order to determine the geothermal water pollution. Grey water footprints related to fifteen geothermal resources were investigated. In the second stage of the study, the effect of biochar adsorption on GWF was estimated using Monte Carlo simulation. The results revealed that arsenic led to higher GWF than other pollutant parameters in geothermal water resources. Biochar application could reduce the GWF according to Monte Carlo simulation. The total average reduction of GWF would be approximately 95, 93.1, 87.5, 96, and 90% respectively for Fe, As, Mn, B and Cr pollution if biochar adsorption is applied for geothermal water treatment. [ABSTRACT FROM AUTHOR]

The noncondensable gases in most geothermal resources include CO2 and smaller amounts of other gases. Currently, the worldwide geothermal power is a small sector within the energy industry, and CO2 emissions related to the utilisation of geothermal resources are consequently small. In some countries, however, such as Turkey and Iceland, geothermal energy production contributes significantly to their energy budget, and their CO2 emissions are relatively significant. SUCCEED is a targeted innovation and research project, which aims to investigate the reinjection of CO2 produced at geothermal power production sites and develop, test, and demonstrate at field scale innovative measurement, monitoring and verification (MMV) technologies that can be used in most CO2 geological storage projects. The project is carried out at two operating geothermal energy production sites, the Kızıldere geothermal field in Turkey and the CarbFix project site at the Hellisheiði geothermal field in Iceland. Together with a brief description of the project, this paper presents the details of the two field sites and the progress made in seismic velocity characterisation and modelling relevant to the Kızıldere geothermal field in Turkey. [ABSTRACT FROM AUTHOR]

This study investigates the sedimentological evolution of the South Danamandıra Lake (SDL) lake in Çatalca Peninsula, 70 km west of İstanbul, using Georadar data and multiproxy analyses of five sediment cores. The lake is a 1.3-m deep, endorheic freshwater peatland, heavily colonised by common reed (Phragmites sp.). The multiproxy core investigations include a lithological core description and environmental magnetism, physical properties (gamma density and magnetic susceptibility), geochemical elemental, pollen and radiocarbon dating analyses. The lithological sequence in the lake consists of an upper peat unit and a lower sand-silt-clay unit. The peat unit is characterized by lower magnetic susceptibility, density and lithophile elements (K, Fe, Ti, and Zr) concentrations than the sand-silt-clay unit. Overall interpretation of the multiproxy data and the age-depth model suggest that the SDL was formed in a shallow depression of a fluvial channel at ca 10.9 cal kyr BP, and became a eutrophic lake at 8.1 cal kyr BP during the early Holocene warm period. Redox-sensitive element (i.e. Mn) distribution and mineral magnetic properties indicate that the peat unit has accumulated under anoxic conditions below a thin oxic surficial layer. Increase in the Taraxacum, Asteraceae, and Poaceae pollen percentages, together with high siliciclastic inputs in the lake, indicate that anthropogenic influence in the area started at 5.4 cal kyr BP [ABSTRACT FROM AUTHOR]

This study reevaluates the published total inorganic carbon (TIC) and total organic carbon (TOC) percentages of 695 seafloor sediment samples collected from the continental margins of the Black Sea, Sea of Marmara, Aegean Sea and Mediterranean Sea between 1984 and 1996. An inverse relationship is observed between the average TIC and TOC percentages in the four seas surrounding Türkiye. The explanation for this phenomenon is closely connected to the terrestrial, marine, climatic, and environmental factors of the continental margins from which the samples were collected. [ABSTRACT FROM AUTHOR]

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. The most distinctive petrographical and geochemical properties in this study are colour, light transmission along with rare-earth element + yttrium (REY) geochemistry, and stable carbon and oxygen isotope data. Two stratigraphic correlations can be maintained for two different marble horizons of the GP-1 well to different stratigraphic horizons outcropping in the study area. Additional Rb-Sr geochronology yields an age of the last metamorphic overprint of the marbles of approximately 30 Ma. This study shows that a multiproxy approach is required to yield a reliable stratigraphic correlation as an important component of geothermal exploration, which supports the conceptual geological model prior to further geothermal drilling. [ABSTRACT FROM AUTHOR]

The pre-Liassic basement of the Biga Peninsula, located in the westernmost part of the Sakarya Zone, consists of metamorphic assemblages that were considered to represent different continental basements in the north and south, and the suture (ophiolitic/mélange) zone(s) between them. The Çetmi mélange, defined as between these continental fragments (the Kazdağ Massif in the south and the Çamlıca Massif in the north) was evaluated as a subduction accretionary mélange of the Intra-Pontide Ocean and it was assumed that a suture passed through this part of the peninsula. This study was carried out on the most widely distributed outcrops of the Çetmi mélange(?) on the northwest flank of the Kazdağ Massif. These units, which are named the Örenli metamorphics, are represented by a succession of low-grade metamorphic volcanic-volcaniclastic rocks and alternating metasedimentary rocks and recrystallized limestones. The tectonostratigraphically lowermost levels of the Örenli metamorphics are a blocky-chaotic assemblage, whereas the uppermost levels are a regular metavolcanic-metapelite succession, which passes upward into the Late Triassic recrystallized limestones, and is cut by very low-grade metamorphic diabase dykes of 165.81 ± 1.55 Ma age. Furthermore, metavolcanic rocks of this succession show a calc-alkaline association of Basalt-Andesite-Dacite-Rhyolite (BADR) pattern in the chemical classification diagram, which is the signature volcanic rock suite of convergent margins. In addition, all the metavolcanic rock samples show a significant enrichment in terms of incompatible elements and LIL elements and negative Nb and Ti anomalies on the MORB normalized multielement spider diagram, which indicates that these rocks characterize high-K calc-alkaline volcanism at the active continental margins. Field relationships, zircon U-Pb geochronology, and geochemical data support that these units, outcropping in the study area, represent a Triassic active continental margin, most probably a fore-arc setting, related to the Paleo-Tethyan subduction, but not the subduction mélange of the Intra-Pontide Ocean. [ABSTRACT FROM AUTHOR]

The mineralogical and chemical characteristics of Upper Cretaceous-Lower Paleocene claystone sediment samples taken from Mardin and Batman, located in southeastern Türkiye, were analyzed in the present study. The clay mineral paragenesis in the Upper Cretaceous units consisted of chlorite-smectite (C-S) and illite, whereas the Lower Paleocene unit consisted of chlorite-vermiculite (C-V) and vermiculite minerals. Analyses conducted on clay samples indicated high levels of Al, Mg, Fe, Cr, V, Ni, and Zr. Low levels of alkali and alkaline earth elements (Mg, Na, Ca, K) in the clay-rich sediments suggest relatively high-grade weathering in the source area. The mineralogical compositions, major elemental ratios, and trace and rare earth element (REE) contents of the sediments indicate that the Upper Cretaceous unit consists of materials with predominantly felsic lithology, whereas relatively detrital contributions from basic sources are found in the Lower Paleocene unit. A comparison of the major and trace element contents of phyllosilicate/clay minerals with the members revealed that the patterns of the clays were distinct from each other. However, the enrichments/depletions varied depending on the origin (basement rocks or detrital) of the derived rocks, minerals, and elements. The major and trace element geochemistry of Upper Cretaceous-Lower Paleocene rocks was associated with a passive margin setting. Sedimentation processes and differences in provenance among members of the Germav Formation during the Cretaceous-Tertiary periods were largely influenced by local or regional geodynamic and diagenetic events. [ABSTRACT FROM AUTHOR]

The Mw 7.7 Pazarcık earthquake on February 06, 2023, struck southern Türkiye, causing typical liquefaction along the shores of İskenderun Bay. This liquefaction was characterized by lateral spreading, subsidence, and flooding. Subsidence-triggered sand ejecta, water flows, and opening cracks were identified in areas spanning approximately 2 km in length and 300 m in width. Based on coastal references such as lighthouses or harbor platforms, settlements of 0.8 m and lateral spreading of 0.4% were recorded along the coastal zone following the Pazarcık earthquake. According to camera recordings, liquefaction-related water and silty sand outflows occurred 29 min after the earthquake. The largest water outlet observed had dimensions of 2 m in length, 1 m in width, and 0.5 m in depth. Images captured at the moment of liquefaction show water gushing for 2 m. Granulometric analysis of liquefied sand eruptions at 10 locations on the coast of İskenderun indicated the presence of silty sand (SM). No water entered the settlement area from the sea during or shortly after the earthquake. The waters that flooded the streets of İskenderun were largely drained or pumped out after remaining for 3 days. The liquefaction of the main soil zone played a crucial role in the collapse or tilting of tall buildings along the shores of İskenderun.Lateral spreading and collapse on the shores of İskenderun were further exacerbated by the MW 6.4 magnitude Defne earthquake that occurred 14 days after the initial major earthquake. Field observations made 25 days after the first earthquake revealed a settlement of 1.7 m and approximately 1% lateral spreading in the coastal zone of İskenderun. [ABSTRACT FROM AUTHOR]

The first MW 7.7 and second MW 7.6 Kahramanmaraş earthquakes were the strongest tectonic events in Eastern Türkiye since the MW 7.9 Erzincan earthquake in 1939. The first and second events occurred on the Pazarcık and Çardak segments of the East Anatolian Fault System, respectively. A subsequent significant earthquake of MW 6.4 occurred in the Antakya fault zone. We summarize preliminary earthquake data and share our previous field observations to better understand the mechanism and provide scientific consequences for future investigations and layout planning. After combining the field observations, kinematic analysis of fault surfaces, investigations of orthophotos, characteristics of mainshocks, and differential interferometry analysis of Sentinel-1A synthetic aperture radar images are used to evaluate the surface deformation from an earth sciences point of view. As a result, field data, paleostress analysis, and deformation zones are found to be completely consistent with the focal mechanism solutions of recent earthquakes. Furthermore, the first MW 7.7 event would have been caused by motion along the Pazarcık and Amanos segments at the same time as a single seismic segment. [ABSTRACT FROM AUTHOR]

Scientific studies concentrated in Antarctica hold great value and importance for humanity. Research projects are conducted in various disciplines on the continent, where nearly 100 research stations from 30 countries are established. Despite the challenges posed by Antarctica's natural structure, unique environment, difficult working conditions, and limited logistics opportunities, scientific research conducted there is indispensable due to the valuable information it offers. In pursuit of accessing this information, Turkish Antarctic expeditions have been organized since 2017. In this study, a polar data center was established through a web-based geographic information system (WebGIS), a significant infrastructure for the continuity of scientific studies. The implemented projects and raw/processed data from previous expeditions in diverse subjects and disciplines, including geology, geophysics, geography, hydrology, meteorology, oceanography, glaciology, atmospheric physics, chemistry, microbiology, and remote sensing, were incorporated into this information system. Studies in Antarctica have primarily focused on observing the effects of global warming, necessitating the monitoring of past and current data related to sea ice, sea level, and coastal changes. The data also encompasses seismic, volcanic, tectonic, and Global Navigation Satellite System (GNSS) monitoring. As suggested by the Antarctic Treaty, a user-friendly website was designed and made accessible for research projects, data, and publications. An entity relationship diagram was created for the fields to be included in the database. These fields were structured as tables using structured query language (SQL) queries in PgAdmin. A workspace and storage area were created in GeoServer, and a connection was established with PostGIS. Layers of spatial and nonspatial data from the PgAdmin application were added to the GeoServer workspace. The data transferred to GeoServer were presented in an OpenLayers web map with Web Map Service (WMS) and Web Feature Service (WFS) according to Open Geospatial Consortium (OGC) standards. Additionally, a mini web map was designed using the desktop Quantum GIS (QGIS) application and GIS Cloud collaboration, displaying GNSS and meteorological (weather) observation stations on the continent. A dynamic web project was employed for coding in Eclipse software, where backend coding was done with JavaScript. SQL was used as a part of the backend to integrate data from the database per request. Frontend coding for the website's visual side was completed with HTML, CSS, and JavaScript. As a result, a WebGIS platform was developed where researchers can register, add projects, and publications, and view data on a map. Users can download, analyze, and utilize the available data. The data center's existence underscores the importance of polar science and serves as an incentive for further research. [ABSTRACT FROM AUTHOR]

The Biga Peninsula in northwestern Anatolia, a part of the Alpine-Himalayan orogenic belt, has a complex geology that was formed following the closure of the northern branch of the Neotethys. Intense volcanism and plutonism in the area from the Eocene to the Middle Miocene period caused several Pb-Zn-Cu±Ag±Au deposits to form. The geometry of the mineralizations is largely made up of polymetallic veins, manto-chimneys, and irregular replacement bodies. Ore-bearing and host rocks in the mineralization zones and the wall rocks outside the mineralization zones were compiled in this study. The most common minerals in the skarn zones are garnet, pyroxene, amphibole, epidote, chlorite, quartz, and calcite, while quartz, calcite, and sericite are formed in the hydrothermal alteration zones. Based on the geochemical analyses, the granitoidic rocks are granodiorite, whereas the volcanic rocks are dacite, andesite, trachyandesite, and basaltic andesite. According to the skarn-forming features, the Biga plutons have chemical characteristics that can form Pb-Zn, Cu, Fe, and Au skarns. The carbonate units in the area are made up of marble (fresh), marble (in the alteration zone), and ore calcite. The geochemical analyses of the carbonate units indicate that in composition the fresh marble is almost pure CaCO3. However, the marble in the alteration zone has higher SiO2, Fe2O3, MgO, and MnO contents than that of the fresh marble. These values are higher in ore calcite. The metasandstones mostly consist of arkose and may have contributed to the main mineralization as they have initial ore element enrichment. According to a hierarchical cluster analysis (HCA) result, three different element groups were detected, these being Sb, Rb, Zr, Ag, Y, Mo, Hg, and Nb (increased during alteration), Sr and Ba (decreasing in alteration), and Cu, Au, As, and Cd (mineralization-related). Rare earth element (REE) characteristics indicate that hydrothermal fluids, responsible for the formation of the Biga Peninsula Pb-Zn deposits, are characterized by very low REE concentrations, and consequently the origin of these fluids is predominantly meteoric. The ∑REE, (Pr/ Yb)cn, Ce/Ce* values (8.63-24.79 ppm, 2.84-8.23, 0.38-0.82, respectively) of the marble in the alteration zone and ore-bearing skarns (3.34-27.20 ppm, 2.32-5.87, 0.36-0.83) support the findings of the meteoric contribution. Based on the similarities of the general trends and the abundances of REE elements in ore-bearing skarns and wall rocks, it is thought that wall rocks may have contributed part of the lead. The δ34S isotope compositions of galena, sphalerite, pyrite, and chalcopyrite fall into a narrow range of around 0‰. This data indicates that the sulfur in the Pb-Zn±Cu sulfides in the Biga Peninsula is of magmatic origin (δ34Smin: -5.5, δ34Smax: 5.2, δ34Savg: -0.7; n: 40). According to the δ34S values, the mineralizations occurred under intermediate sulfidation conditions, in a reducing environment with H2S-dominant fluids with a near neutral pH value. [ABSTRACT FROM AUTHOR]

Geochemical investigations carried out on thermal waters over the Erzin-Hatay area allowed the collection of a suite of 9 samples from natural springs and one well characterized by outlet temperatures in the range from 19.6 to 31.5 °C. All of the springs have slightly acidic pH (in the range of 6) but one sample was marked by a pH value >11 as a consequence of serpentinization processes. The water chemistry denotes water/rock interactions with either magmatic or carbonatic rocks in a water reservoir equilibrated at temperatures estimated to be in the range of 58-162 °C. The stable isotope composition of the collected waters, in terms of dD and d18O, denotes a recharge from local meteoric waters. The dissolved gases denote the contribution of no atmospheric components. CO2 is the dominant dissolved component for most of the sample, while methane is the major component for the thermal water involved in serpentinization. Besides the main components CO2 and CH4, the dissolved gases show significant concentrations of He, H2, and CO. The isotopic composition of helium shows ³He/4He ratios well above that of Air Saturated Waters (ASW = 1.39 x 10-6) clearly indicating a significant contribution of 3He of mantle origin. Taking into account the location of some sampling sites nearby the Düziçiİskenderun Active Fault Zone and the associated mantle helium contribution, we propose that fluids/faults relationships have to be considered as responsible for the feeding of deep-originated fluids to the shallow groundwater. As mantle-derived fluids are also carriers of thermal energy, the collected results strongly suggest improving the knowledge of the study area, where hydrological and geochemical considerations coupled with the tectonic setting of the area should focus on the geothermal potential of the circulating waters. [ABSTRACT FROM AUTHOR]

The Eastern Pontides Orogenic Belt (EPOB), geographically corresponding to the northeastern part of Turkey hosts several different types of mineralizations that are closely related to Late Mesozoic-Early Cenozoic arc magmatism. Of these, Zarani gold mineralization, which is located in the southern part of the EPOB occurs as quartz-carbonate veins/veinlets within the Pulur metamorphic massif of Paleozoic age. Mineral textures indicate low-temperature vein-type mineralization. Gold mainly occurs in quartz and pyrite. The presence of calcite, dolomite, and sericite in the mineralization indicates near neutral pH conditions of ore-forming fluid. Geochemical analyses of chlorites in the quartz-carbonate veins reveal a temperature of ore formation at 140-297 °C, which is compatible with those obtained from fluid inclusions in the mineralized quartz (i.e. 132-226 °C). The average salinity value obtained from fluid inclusions is 4.32% NaCl equiv. O and H isotope values range from -6.03? to +1.47? and from -60? to -119?, respectively, indicating a mixture of magmatic and meteoric fluids. Mixing is also evidenced by the XFe analytical data of hydrothermal chlorites associated with ore-forming gangue minerals. Gold precipitation in Zarani mineralization is caused by boiling. The occurrence of mineralization within quartz-carbonate vein/veinlets in metamorphic host rocks, the mineral paragenesis with near-neutral pH conditions of the ore-forming low salinity fluids and the H-O isotopic data imply that the Zarani gold mineralization is an orogenic type epithermal mineralization that may be related to deeply buried Early Cenozoic felsic intrusions, produced by subduction-induced processes in the southern part of the EPOB. [ABSTRACT FROM AUTHOR]

The age and depositional environment of the Harami Formation were reevaluated based on the new larger benthic foraminiferal (LBF) data. LBF assemblage including Orbitoides medius (d'Archiac), O. megaloformis Papp and Küpper, O. gruenbachensis Papp, Pseudomphalocyclus blumenthali Meriç, Omphalocyclus macroporus (Lamarck), Sirtina cf. orbitoidiformis Brönnimann and Wirz, Hellenocyclina beotica Reichel, Lepidorbitoides campaniensis Van Gorsel, L. bisambergensis (Jaeger), L. cf. minor (Schlumberger), Pseudosiderolites vidali (Douville), and Siderolites gr. calcitrapoides Lamarck were determined in the formation. Based on this LBF assemblage data, the late Campanian-Maastrichtian age was assigned to the formation. The paleontological and sedimentological data indicate that the Harami Formation was deposited on a shallow ramp environment. [ABSTRACT FROM AUTHOR]

The Bitlis-Zagros Fold-Thrust Belt is one of the world's largest deformation zones, extending from the Eastern Mediterranean in southern Turkey to in the south of Iran. This deformation zone is partitioned between different structures; however, little is known about the relative activities of these different structures and their effects on topography. An area located in the northern part of Bitlis-Zagros Fold-Thrust Belt, just south of the Eastern Anatolian Plateau was studied in detail to analyze the effect of active tectonism on topographic development. The effects of active deformation structures such as Hakkâri and Şirvan Fault Segments on the topographic evolution of Kato Folds and Sinebel Valley were investigated to understand the fold and thrust fault activity. Geomorphic indices were used, such as HC, HI, SR, Ksn together with rose analysis based on bedding measurements. Investigation of folding in the region indicates the effective stress regime in the precollision zone was in NW-SE compression direction. The deformation structures, effective in the postcollision zone developed due to N-S directional compression, and are shown here to have different effects on topography of the region. This study has shown the relative uplift rate is highest in the areas where Hakkâri and Şirvan Segments are pure thrust faults (0.4 mm year-1), and lower in the transfer zone (0.2 to 0.4 mm year-1) between the segments. As a result of this study, it is concluded that the main deformation structures controlling the topography in the region are not only thrust faults, but also structures that develop in the area of transfer zone. [ABSTRACT FROM AUTHOR]

The Eastern Anatolian Plateau (EAP), approximately 2000 m above sea level, is located between the Eastern Pontides to the north, the Arabian Platform to the south, and the Iranian Plateau to the east. It is characterized by approximately 6 km-thick Maastrichtian to Quaternary volcano-sedimentary cover which unconformably overlies continental and oceanic basement units. Overall, the outcrops of the pre-Maastrichtian basement are rare and include both continental and oceanic units. This led to drastically different interpretations of the nature of the pre-Maastrichtian basement as (i) the oceanic accretionary complex or (ii) continental crust and overlying ophiolitic mélange. This synthesis deals with the relationships between continental and oceanic units in light of the recent geological, geophysical, and geochemical studies. Geophysical studies consistently indicate the presence of a spatially thickened continental crust with a lateral variation ranging from 38 to 52 km. Seismological models estimate lithospheric thicknesses to be in the range of 70-80 km, suggesting the presence of a rather thinned lithosphere. The pre-Maastrichtian continental units include late Cretaceous high-T/low-P metamorphic rocks, which are intruded by late Cretaceous basic to acidic intrusions at the base. Protoliths of the high-T/low-P metamorphic rocks can be closely correlated with those of the Anatolide-Tauride Block, probably representing the metamorphosed equivalents of the Anatolide-Tauride Block. The continental crustal nature is also testified by the presence of metasyenite to -granite with igneous crystallization ages of 430-440 Ma. The Late Cretaceous ophiolitic mélanges with locally intact tracks of ophiolite and overlying forearc deposits tectonically sit over the Late Cretaceous high-T/low-P metamorphic rocks. These ophiolitic mélanges probably form part of the North Anatolian ophiolitic belt, related to the İzmir-Ankara-Erzincan suture. Maastrichtian to Quaternary volcano-sedimentary rocks overlie both the continental crustal and tectonically overlying oceanic units, representing probably collisional and postcollisional basin fills. Available geological, geochemical, and geophysical data suggest a pre-Maastrichtian basement that comprises a continental crustal domain and an overlying ophiolitic mélange beneath the Masstrichtian to Quaternary cover. [ABSTRACT FROM AUTHOR]

We map surface deformation in the Thrace region of Turkey using the Sentinel-1 Synthetic Aperture Radar (SAR) data. Interferometric Synthetic Aperture Radar (InSAR) time series analysis of the SAR data acquired between 2014 and 2020 on ascending and descending orbits reveals large-scale subsidence (~110 x 60 km) with rates reaching up to 10 ± 1.5 mm/yr. We relate this deformation to natural gas reservoir operations, such as gas exploitation and extraction activities that have been taking place in the region for decades, an inference being supported by the strong correlation between the InSAR time series and the variation in natural gas production during the same time period in the Thrace region reported by the Energy Market Regulation Authority of Turkey. Assuming that the observed subsidence is caused by compaction of sediments in the natural gas reservoirs, we construct a triangulated surface enveloping roughly at the bottom of the gas extraction wells and use it to invert the amount of negative opening (hence volume loss) on triangular elements that are assumed to be buried in an elastic and homogeneous medium. Coulomb stress changes caused by this volume change on the North Anatolian Fault at the Sea of Marmara are found to be insignificant (less than 10-5 Mega-Pascal) to perturb the state of the stress around the Marmara seismic gap. Yet, the large-scale subsidence revealed in this study needs to be taken into consideration when assessing hazards for the infrastructures, settlements, and other engineering structures, particularly in case of a large earthquake in the Marmara Seismic Gap. [ABSTRACT FROM AUTHOR]

GNSS observations in and around the Aegean Sea, Peloponnese, and western Turkey are sufficiently precise and densely spaced to provide an image of the deformation associated with the Hellenic subduction zone. To isolate deformation associated with the plate boundary, we use GNSS secular velocities and shallow earthquake locations to determine an upper plate reference frame with low internal deformation (<2 mm/yr) that includes a large area of the central and western Aegean. We interpret upper plate deformation as resulting from stronger coupling on the subduction plate interface beneath western Crete than on the western or eastern segments of the Hellenic subduction zone, and the geometry of the subducting plate along-strike. If the long-term tectonic extension of the Aegean upper plate counteracts some of the contractional deformation signal from elastic strain accumulation on the subduction interface, as measured at the surface, the coupling coefficient may be as high as 40% around western Crete, although this is the upper limit. [ABSTRACT FROM AUTHOR]

We present a broad view of present-day motions and deformations derived from uniform processing of GNSS observations within the Nubia-Arabia-Eurasia zone of plate interaction. The new observations we present provide a ~29% increase in the number of velocity determinations, a reduction in average station spacing from ~76 km to ~39 km, and an improvement in velocity uncertainties (for <1 mm/year), from 180 to 578 sites compared to our prior published solution (Reilinger et al., 2006). We use these new constraints to better evaluate the role of faults and blocks in controlling the character of continental deformation within the zone of plate interactions. Simple elastic block models show that internal deformation of the region occurs in large part on mapped, seismically active fault systems, indicating elastic behavior of the seismogenic crust (above ~15 km). For example, eastern central Anatolia, an area of > ~126,000 km², bounded by the North and East Anatolian Faults exhibits internal velocity differences of <0.5 mm/year, indicating strain rates of < ~1.5 nanostrain/year. Geodetically constrained fault slip rates obtained from this simplified approach are comparable to geologic rates, indicating that major faults have controlled the recent geologic evolution of the region (i.e. 5-10 Myr). The pattern of present-day deformation, including increasingly fast motions towards the Hellenic trench, and the roughly simultaneous opening of all the major Mediterranean basins in the early Miocene with the slowing of the Nubia-Eurasia convergence, support conceptual models that foundering and rollback of the subducted Nubian slab beneath the Aegean is the primary mechanism responsible for present-day motion and internal deformation of the Anatolian-Aegean region. [ABSTRACT FROM AUTHOR]

We investigate the geology and petrology of Cumaçay, one of the Plio-Quaternary eruption centers of postcollisional volcanism in Eastern Turkey, using a combination of geochronology, bulk-rock geochemistry, thermobarometry, and thermodynamic simulations. Our new K-Ar ages reveal an age of 3.5-0.97 Ma for the eruptive products, which spread around an area of approximately 1000 km². Mineral-melt equilibria for olivine, orthopyroxene, clinopyroxene, and plagioclase allow estimation of crystallization pressures, and temperatures indicate two separate crustal storage of crystallization at 14-28 km and 5-15 km. The temperature estimation from diverse methods ranges from 954 °C to 1224 °C. Thermodynamic modelings using Magma Chamber Simulator (MCS) at a representative pressure (5 kbar) imply that the assimilation and crustal contamination (AFC) resulted in evolved melts with various SiO2 contents at mid to lower crustal depths. Calculated wide range of temperatures, compositional variety from evolved members, and MCS recharge simulation at a representative pressure (2.5 kbar) reveal that the magma mixing between contrasted melts characterizes the final chemical dispersal of the erupted lavas. [ABSTRACT FROM AUTHOR]

The Afşar section, situated in the Dombayova graben in western Turkey, is one of the key localities for the study of the Pliocene of Anatolia. Two fossiliferous layers yielded micromammal assemblages, including various cricetine and arvicoline species. These include the species Mimomys cf. gracilis, Pliomys sp., Arvicolinae gen. sp. and the cricetines Cricetulus cf. ehiki and Cricetulus sp. in Afşar 1 and Mimomys hassiacus, M. gracilis, Pliomys graecus and Mesocricetus primitivus in Afşar 2. The cooccurence of these species indicates a dry and open spaced habitat. Based on the composition and stage of evolution of the hamster and vole species, Afşar 1 assemblage can be referred to MN 15 or early MN 16 with Afşar 2 being assigned to early MN 16. [ABSTRACT FROM AUTHOR]

Bademli geothermal area (BGA) is located on the coastline of Dikili-İzmir province and consists of Bademli spring and Hayıtlı areas with 36.8-51°C discharge temperatures, respectively. The waters of Hayıtlı borehole have remarkable seawater mixing ratios like Bademli spring and have Na-Cl water type. Dikili group pyroclastic volcanic units constitute the reservoir rock in the entire geothermal area. The heat source is relatively elevated geothermal gradient caused by extensional tectonics forming E-W trending grabens. Bademli thermal water is plotted in the "immature waters" area in the Na-K-Mg triangular diagram with a calculated seawater contribution of 18%. Therefore, some cation geothermometers are considered unreliable. On the other hand, the silica-enthalpy diagram showed an anticipated reservoir temperature of approximately 240 °C. Hayıtlı borehole water sample is plotted on the "partially equilibrated waters" area in the same triangular diagram and shows a reservoir temperature of 208 °C. The seawater contribution in the Hayıtlı area (16%) is less than the Bademli spring. On the other hand, based on the K/Mg geothermometry, the reservoir temperatures for Bademli spring and Hayıtlı borehole waters are 129 °C and 138 °C, respectively. B, Fe, Mn, and Sb concentrations exceed the tolerance limits of the EPA and Turkish drinking water standards in the area. In addition, due to silica-rich volcanic rocks, Ge solubility increased with temperature in thermal waters and reached 34-45 µg/L. Enrichment of δ18O and δ²D values can be observed in Bademli spring and Hayıtlı with -3.70‰ and -4.63‰, and -34.5‰ and -37.9‰, respectively. From the chemical and isotopic results, it can be clearly said that this coastal geothermal area is high enthalpy, as evident from the equilibrium temperatures. However, when the thermal water rises to the surface, it mixes with both cold groundwater and modern seawater resulting in a decrease of the discharge temperatures of the springs. Moreover, according to the isotopic and hydrogeochemical data, the area has a high potential for thermal heating of the settlements in the area. [ABSTRACT FROM AUTHOR]

We investigate the multiphase deformation, fluid flow, and mineralization processes in epithermal systems by presenting a detailed study of vein textures and breccias of the Kestanelik epithermal Au-Ag deposit, NW Turkey. The mineralization in the deposit is associated with several quartz veins. Fault-hosted veins and mode I veins share many textural and breccia characteristics owing to (i) overprinting of tectonic breccias formed during coseismic rupturing by subsequent coseismic hydrothermal brecciation and (ii) reworking of earlier vein breccia phases by repeated rupturing and hydraulic fracturing events. The spatial distribution of breccias at fault-hosted veins proposes that power of coseismic hydrothermal brecciation is controlled by the distance to the level of boiling within a vein. The brecciation affects the entire vein proximal to the level of boiling; however, it is limited to the footwall contact of the vein more distally at the upper levels of a vein. Varying number of mineralization events for the veins suggests that any individual earthquake event reopened only one or more sealed vein, but not all at once. Fewer mineralization events in fault-hosted veins compared to the mode I veins is either linked to (i) focusing of high fluid flux into the conduits of mode I veins that accommodate more dilation or (ii) reopening of mode I veins owing to the driven of extensional failure under low differential stress. Although fault-hosted veins record fewer mineralization events, they have higher average Au grade (4.106 g/t) compared to that of mode I veins (2.736 g/t). On the other hand, fewer mineralization events in wall rock structures compared to the adjacent faults is attributed to (i) absence or poor development of the damage zone structures in earlier seismic events or (ii) deactivation of them after clogging due to the rotation of the optimum stress field or (iii) their formation as hydraulic extension fractures. This study emphasizes the importance of detailed studies of vein infill for understanding the internal structural evolution of the veins in epithermal deposits that is interest to the geologists within both industry and academic fields. [ABSTRACT FROM AUTHOR]

Pithonellid calcitarchs are studied in the organic-rich limestones of the Derdere-A Member from the middle? Cenomanian deposits of SE Turkey for the first time. Little is known about the distribution of pithonellid calcitarchs in the Cretaceous strata of Turkey. Three morphogroups of pithonellid calcitarchs are distinguished: they are represented by Pithonella sphaerica (Kaufmann, 1865) and P. ovalis (Kaufmann, 1865), both dominating the pithonellid assemblages, and by Bonetocardiella conoidea (Bonet, 1956), this latter being less abundant. Compared to the relative abundance of Upper Cretaceous pithonellid calcitarchs in the study area, the diversity is extremely low. The significant increase in abundance of pithonellid calcitarchs is particularly noticeable in the Cenomanian. We observed a significant increase in abundance of pithonellid calcitarchs in the Derdere-A Member, which is associated with an early transgressive phase of the middle? Cenomanian Arabian Platform. They are present in relative abundance and could therefore represent a potentially useful correlative marker horizon in SE Turkey. Pithonellid calcitarchs have been interpreted as indicators of increased nutrient input. A positive correlation exist between pithonellid calcitarchs abundance and nutrition input in the Derdere-A Member which is a sequence of carbonates deposite under eutrophic conditions, as evidenced by the low diversity and very low abundance of benthonic and planktonic foraminifers, and the high abundance of pithonellid calcitarchs. As a result, the increase of pithonellid calcitarchs indicates the increase of nutrient input in the Derdere-A Member. We noticed that a comparable trophic change also occurred throughout the SE Turkey carbonate platform in the middle? Cenomanian. The increase in the pithonellid abundance reported here may be a possible indicator of such a change. [ABSTRACT FROM AUTHOR]

New field observations and discovery of calcareous nannofossils and planktonic foraminifera from the 'shallow-marine' Çayraz Formation (Haymana Basin, Central Anatolia), a contributing Eocene section to the shallow benthic zonation (SBZ) in the Tethys, allow us to revise its stratigraphy and establish an integrated biostratigraphic scheme for the first time. The hemipelagic marls in the uppermost part of the Eskipolatlı Formation that underlies the Çayraz Formation yielded nannofossil assemblages of Zone CNE3, pinning down the initiation of the Çayraz shelf system into the 'middle' Ypresian. The prominent marly part (Member B) between the carbonate-clastic packages of the Çayraz Formation with prolific occurrences of larger benthic foraminifers (LBFs) (Members A below and C above) yielded calcareous nannofossils suggesting Zone CNE6 (late Ypresian). We show that the mixed carbonate-siliciclastic sequence with abundant LBFs in the upper part of the formation (Member C) is overlain by newly discovered hemipelagic marls (here named as Member D). These marls yielded calcareous nannofossils indicating Zone CNE9 and CNE10 for the lower and Zone CNE12(?Lutetian) for the upper samples. The same beds yielded planktonic foraminifers indicating Zone E8 for the lower and Zone E9 for the upper samples. We conclude that shallow-marine sedimentation in the Çayraz section ended in the 'middle' Lutetian, challenging the previous Bartonian records by LBFs. A new lithostratigraphic scheme consisting of four members with distinctive lithological and biotic characteristics is proposed for the Çayraz Formation: two main shelf systems (Members A and C), each followed by deep-marine sedimentation (Members B and D). [ABSTRACT FROM AUTHOR]

Devonian shallow marine carbonate rocks of the Taurides (southern Turkey) host rich and diverse faunal assemblages of foraminifera including unilocular organisms of the family Parathuramminidae. This study allowed investigating the calcareous unilocular parathuramminid fauna obtained from three measured stratigraphic sections Halevikdere, Kocadere and Eceli in addition to one detailed, shorter section measured along the Halevikdere section. The investigation revealed that the parathuramminid species, which commonly occur in lagoonal environments, are widely distributed throughout the studied sections. They mostly exist in limestone beds deposited in a time interval from Middle Devonian (Eifelian) to Late Devonian (Frasnian). However, their richness and diversity increased in Givetian period. The systematics of the family Parathuramminidae in the region is here provided. The family consists of 25 species belonging to two subfamilies Parathurammininae and Parathuramminitinae including Proninellites, new genus, and Sabirovellites altineri, new genus, new species. A practical identification key for the parathuramminid genera is introduced. [ABSTRACT FROM AUTHOR]

Red soils as the weathering products in Muğla Polje (SW Turkey) show different occurrences either on hard and permeable limestone (terra rossa (TRs)) or within the matrix of transported sediments (alluvium-derived soils (ALs), alluvium-derived soils specifically from clastics (ALsc), paleosol (Pls), and colluvium-derived soils (CLs)). The purpose of this study is to unlock the effect of weathering on hard carbonate rocks and dynamic young land surfaces (alluvium and colluvium) in Muğla Polje for the first time in terms of mineralogical and geochemical compositions. TRs, the soils of more stable environments are clayey while ALs and CLs as being the soils of dynamic environments have variable textures from silty clay loam to sandy loam. All soils share low CEC property (13-16.8 meq/100 g for TRs; 2-11.6 meq/100g for ALs and CLs). Nonclay components of the samples include quartz, feldspars, calcite, dolomite, and mica minerals. Hematite is observed as the main reddening agent for all samples. Illite, kaolinite, chlorite, and vermiculite are the clay minerals of the fine fractions. TRs are characterized by low intensity of salinization (<1) and calcification (<2), high degree of clayeyness (>0.3), and intense hydrolysis due to very high CIA and CIA-K (84%-88% and 89%-93%) under very high MAP (1230-1285 mm year-1). ALs and CLs are the soils with moderate to high calcification (>2), low salinization (<1), high base amounts (70-522; 73-141), low intensity of leaching developed under low CIA and CIA-K (3%-22% and 10%-16%) due to low MAP (<270 and <197 mm year-1). Samples of Pls and ALsc are also qualified with low salinization (<1), low calcification (<2), and intense leaching (>0.2) associated with very high CIA and CIA-K (>80%, >90%) under very high MAP (>1260 mm year-1). Therefore, this study suggests that TRs are the results of intense weathering on carbonate rocks of more stable environments while ALs and CLs are the products of weathering of much lower intensity on alluvium and colluvium. As more mature soils of the polje, TRs also contribute to the matrix of the transported sediments in the lowlands of the polje. [ABSTRACT FROM AUTHOR]

Recently, several Devonian localities and the related biota occurring from the southeastern Turkey were reinvestigated. Although, the Hakkari-Çukurca and the Diyarbakır-Hazro areas of the Arabian Plate are considered as an important source of the Devonian macrofossils from the north Arabian sector of Gondwana, the existing record of Devonian trilobites in these regions was hitherto unknown. We here report and illustrate for the first time Lower and Middle Devonian trilobites represented by three proetid pygidia and one calymenid pygidium. The morphological features of these pygidia suggest that they can be assigned to undetermined species of Gravicalymene (Calymenidae) and Podoliproetus (Proetidae), two genera known in the Lochkovian; and Pseudodechenella (Proetidae), a genus known in the Givetian. [ABSTRACT FROM AUTHOR]

In this study, we present pollen records together with a multiproxy analysis from a sediment core collected from the Güllük Bay (Bargilya Cove, Muğla, SW Turkey), covering the last 400 years. Pistachio shrubland was occupying around the Güllük Bay between 1613 and 1741 AD. However, after 1741 AD, the vegetation canopy suddenly changed and Turkish pine (Pinus brutia) was established. This supports that the main factor affecting the expansion of Pistacia lentiscus was precipitation rather than temperature after 1741 AD. This change is also indicated by high Sr-Ca values, reflecting arid conditions. Two anthropogenic phases developed in the region. The first phase is marked by Olea europeae between 1613 and 1789 AD. The second is characterized by Plantago, Caryophyllaceae, Cerelia, Rumex, and Sanguisorba minor type suggesting pastoralism and agricultural activities between 1789 and 1964 AD. Macrofaunal communities are also indicative of environmental changes. Abra ovata, Cerastoderma glaucum, Bittium reticulatum, and Skenea catenoides were first settlers between 1572 and 1643 AD. The prominent presence of lagoonal species Abra ovata and Hydrobia ventrosa indicates a lagoonal depositional environment in 1799-1948 AD. [ABSTRACT FROM AUTHOR]

Western Anatolia is known as one of the most seismically active regions in the world, consistent with earthquakes having a magnitude >6.0. The deformation in the region is predominantly controlled by normal faults, which play significant role on the morphological features as well as depositional processes in related grabens. WNW-trending Kütahya Graben is located at the northeastern part of this province and bounded by several N- and S-dipping active normal fault segments. This study aims to investigate the relative tectonic activity among the fault segments of the Kütahya Graben using geomorphic indices. The analyses of this study include mountain-front sinuosity (Smf: 1.06–1.92), triangular facets (Lf/Ls: 0.11–0.94), valley floor width-to valley height ratio (Vf: 0.19–2.83), hypsometric curve and integral (HI: 0.34–0.48), asymmetry factor, stream length-gradient, and relative tectonic activity indexes. These indices suggest relatively higher uplift rates (>0.5 mm/yr) and tectonic activity for the southern margin of the graben where Kütahya city center is located. Thus, southern segments of the Kütahya Graben need further attention in terms of regional seismic hazard. [ABSTRACT FROM AUTHOR]

Şenkaya chrysoprase is a gemstone and can be found near the Turnalı village located in the west-northwest of Şenkaya (Erzurum) county in the uplifted Kırdağ of Northeast Anatolia of Turkey. Chrysoprase only found in Şenkaya County and known with the same name commercially in Turkey is a light-dark green and cryptocrystalline structure gemstone encountered in the Örükyayla Mélange. Samples were collected from the field for defining mineralogical-petrographical, XRD, XRF, ICP-MS, optical cathodoluminescence microscopy (OCLM), FTIR-Raman and stable isotopic properties of Şenkaya chrysoprase. According to mineralogical and petrographic examination, Şenkaya chrysoprase has generally heterogeneous color distribution in macroscale and has 5 Mohs mineral hardness. Microquartz filling (10%-15%) was seen in the microexamination with serpentine as main component with partly massive opal type silica. The XRF analyses indicate that many samples had high SiO2 values (91.45-94.38 wt%). As a result of trace elements, rare earth elements, Au-Pt group analyses using ICP-MS, Ni (167-387 ppm) and Co (12.57-74.78 ppm) values are quite remarkable. In the OCLM studies, few metallic minerals which could produce CL and could spread CL in different colors due to some trace activator elements were observed. Oxygen isotopic (d18OV-SMOW) values obtained from three chrysoprase samples are 24.8‰, 27.7‰ and 30.63‰, respectively and mean formation temperature is 96-99 oC. [ABSTRACT FROM AUTHOR]

Field observations and morphotectonic evaluations on the south of Ulubat Lake and the Susurluk valley show that the dominant active fault pattern consists of northeast-southwest and east northeast-west southwest right-lateral faults and northwestsoutheast normal faults developing between these strike-slip faults. We redefined the active faults in the south of Ulubat Lake and discovered that these northeast-southwest right-lateral faults control the route of Susurluk River. Based on these discoveries and evaluations, we can claim that the "bend model" previously proposed for the region is not valid, as seen in the Mustafakemalpaşa Fault and Balıkesir-Kepsut Fault examples. Instead, we suggest that the faults belonging to the southern branch of the North Anatolian Fault Zone extend to Akhisar and İzmir via Bursa, Susurluk, and Balıkesir. [ABSTRACT FROM AUTHOR]

Petrified wood samples are found within terrestrial sediments belonging to the Late Oligocene-Early Miocene Danişmen Formation in Malkara-Keşan located in the southwest of the Thrace Basin. The petrified wood in both regions is usually silicified and partly coalified. The silicification of the Tertiary wood in the Malkara-Keşan region is associated with volcanic activity and coeval sedimentation. Thin sections from petrified wood samples were taken as transverse, tangential, and radial sections. The mineralogicalpetrographic- botanical studies were carried out under a polarizing and botanical microscope. Opal-moganite-chalcedony-quartz, which are different polymorphs of silica, were detected under the microscope in the petrified wood. Results were supported by X-Ray Diffractometer (XRD), Confocal Raman Spectroscopy, Fourier Transform Infrared Spectroscopy (FT-IR) analysis, and measurement of density in a total of five samples. In addition, scanning electron microscopy (SEM/EDS) was performed for textures and to determine the average elementary composition of wood samples. Results showed that while crystalline quartz and chalcedony were well defined, opal-A and other polymorphs of silica could be partly examined due to isotropic features. As a result of XRD studies of petrified wood samples from the Keşan and Malkara regions, the peaks of the crystalline types of silica were well defined in the diffractogram patterns. As a result of FT-IR analysis, polymorphs of silica such as quartz-chalcedony-moganite and mineralogical elements similar to carbon and graphite were detected. In two samples, the densities of chalcedony and quartz composition were 2.35 and 2.27 g/cm3, respectively. Furthermore, the average elementary composition was detected with SEM-EDS analysis as O, Si, S, Ca, Cr, and Fe elements in the Keşan region samples and O, Si, S, and Fe elements in the Malkara region samples. The results of all investigations and analyses were interpreted to understand the geodynamic evolution and paleobotanical properties of the region. [ABSTRACT FROM AUTHOR]

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. Generally, high values are observed around the grabens of Menderes Massif due to the intense tectonic activity. We also present the 2D steady-state thermal model of Gediz. The modeled temperatures are validated by temperature measurements from two deep wells. Numerical simulation results show that the dominant heat transfer mechanism in Gediz graben can be explained by conduction. Temperature distribution in the deep subsurface of the graben is controlled by both thickness distribution and thermal properties of the different stratigraphic sections. Thermal conductivity contrast between different stratigraphic sections causes anomalously elevated heat flow values at the edges of the graben. The comprehensive results of this study will bring a new perspective to geothermal studies in particular Enhanced Geothermal Systems (EGS) resource estimations in Gediz graben. [ABSTRACT FROM AUTHOR]

The Eastern Anatolian Fault Zone (EAFZ), having a prominent place in the tectonic evolution of the Eastern Mediterranean, is a structural element of tectonic indentor due to the convergence between the African-Arabian plates and the Eurasian Plate. This study investigates the central part of EAFZ between Doğanyol (Malatya) and Çelikhan (Adıyaman). The geometry of the fault and the morphotectonic structures were determined by the field studies. Moreover, fault-slip data are measured according to the fault planes along the deformation zone for paleostress analysis. The paleostress analysis revealed three deformation phases that developed from the Late Eocene to the present due to the convergence between the Arabian Plate and the Anatolian Block. The first deformation phase is characterized by NW-SE compressional stress between Late Eocene and Late Oligocene periods. The second deformation phase is related to N-S compressional stress from the Middle Miocene to Pliocene. The most recent deformation phase shows the strike-slip faulting under the NNE-SSW compressional stress from the Late Pliocene to the present. The EAFZ developed during the last phase of these deformation stages. In addition, elongated ridges parallel to the fault, sinistral offsets of drainage networks, linear valleys, and fault terraces observed along the segment show that the study area exhibits active tectonic morphology of the EAFZ. The distribution of seismic activity that occurred during and after the recent mainshock (24 January 2020, Sivrice-Doğanyol earthquake) is compatible with the geometry of the segment and confirms strongly the active tectonics of the segment. [ABSTRACT FROM AUTHOR]