: A high-resolution two-dimensional tomographic velocity image in the eastern Marmara region along a 1.2 km long N-S trending seismic profile, which crosses the surface rupture of the İzmit earthquake on the North Anatolian Fault (NAF) is presented. A vibroseis source at more than 180 points with 50 receivers was used along the long profile. A regularized inversion technique was applied to the first arrival travel times. More than 6500 first arrivals from 129 shot gathers were analyzed to construct velocity images and were qualitatively evaluated for the fault zone-related effects. The velocity model was constrained to a maximum depth of 175 m. The results indicate a fault zone of ~100 m thick with clear velocity contrasts with surrounding blocks. The P wave velocity on the southern block varies between a range of 1.4–1.7 km/s and 1.7–2.0 km/s on the northern block the velocity decreases to 1.4 km/s within the fault zone down to 100–150 m depth. Three component recordings and fan shots also indicate the presence of the fault zone consistent with the tomographic image.
{"title":"A controlled source tomography in Sarımeşe, İzmit, at the western section of North Anatolian Fault Zone","authors":"Tuğçe Ergün","doi":"10.55730/1300-0985.1866","DOIUrl":"https://doi.org/10.55730/1300-0985.1866","url":null,"abstract":": A high-resolution two-dimensional tomographic velocity image in the eastern Marmara region along a 1.2 km long N-S trending seismic profile, which crosses the surface rupture of the İzmit earthquake on the North Anatolian Fault (NAF) is presented. A vibroseis source at more than 180 points with 50 receivers was used along the long profile. A regularized inversion technique was applied to the first arrival travel times. More than 6500 first arrivals from 129 shot gathers were analyzed to construct velocity images and were qualitatively evaluated for the fault zone-related effects. The velocity model was constrained to a maximum depth of 175 m. The results indicate a fault zone of ~100 m thick with clear velocity contrasts with surrounding blocks. The P wave velocity on the southern block varies between a range of 1.4–1.7 km/s and 1.7–2.0 km/s on the northern block the velocity decreases to 1.4 km/s within the fault zone down to 100–150 m depth. Three component recordings and fan shots also indicate the presence of the fault zone consistent with the tomographic image.","PeriodicalId":49411,"journal":{"name":"Turkish Journal of Earth Sciences","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2023-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45360448","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Necati Tüysüz, Gülten Yaylali Abanuz, Oğuzhan Gümrük, Bahrican Ar
: 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 X Fe 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.
{"title":"Textural and genetic investigations of gold mineralization in fault-controlled quartzcarbonate veins in Bayburt-Zarani area (Eastern Pontides-NE Turkey)","authors":"Necati Tüysüz, Gülten Yaylali Abanuz, Oğuzhan Gümrük, Bahrican Ar","doi":"10.55730/1300-0985.1863","DOIUrl":"https://doi.org/10.55730/1300-0985.1863","url":null,"abstract":": 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 X Fe 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.","PeriodicalId":49411,"journal":{"name":"Turkish Journal of Earth Sciences","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2023-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41337114","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Özalp, Hasan Elmacı, Ayhan Yavuzoğlu, Meryem Kara
: The Anamas Block is located at the apex of the Isparta Angle which is one of the most important tectonic structures of Anatolia. The Isparta Angle, which has a complex tectonic structure, was formed as a result of compressional and extensional tectonic events that initiated from the Late Cretaceous continuing to the present. The GPS and kinematic data indicate the Anamas Block currently rotates clockwise due to the impact of the normal faults (Beyşehir Gölü and Sarıidris) with a minor right lateral strike-slip component on the east and west boundaries, while it is moved to the southeast by the effect of the normal fault (Gelendost) bounding the block from the north. In this study, paleoseismological trench investigations were carried out on the Sarıidris, Gelendost and Beyşehir Gölü faults. Data related with activity and fault kinematics of all three faults during the Late Pleistocene-Holocene period was collected on the trench walls. Sedimentological and structural evidences were observed for one earthquake on the Sarıidris, Beyşehir Gölü faults, and two earthquakes on the Gelendost Fault, which resulted in surface rupture during the Late Pleistocene-Holocene period.
{"title":"Characteristic features and paleoseismological behaviours of the Anamas Block Boundary Faults, Southwestern Anatolia, Turkey","authors":"S. Özalp, Hasan Elmacı, Ayhan Yavuzoğlu, Meryem Kara","doi":"10.55730/1300-0985.1864","DOIUrl":"https://doi.org/10.55730/1300-0985.1864","url":null,"abstract":": The Anamas Block is located at the apex of the Isparta Angle which is one of the most important tectonic structures of Anatolia. The Isparta Angle, which has a complex tectonic structure, was formed as a result of compressional and extensional tectonic events that initiated from the Late Cretaceous continuing to the present. The GPS and kinematic data indicate the Anamas Block currently rotates clockwise due to the impact of the normal faults (Beyşehir Gölü and Sarıidris) with a minor right lateral strike-slip component on the east and west boundaries, while it is moved to the southeast by the effect of the normal fault (Gelendost) bounding the block from the north. In this study, paleoseismological trench investigations were carried out on the Sarıidris, Gelendost and Beyşehir Gölü faults. Data related with activity and fault kinematics of all three faults during the Late Pleistocene-Holocene period was collected on the trench walls. Sedimentological and structural evidences were observed for one earthquake on the Sarıidris, Beyşehir Gölü faults, and two earthquakes on the Gelendost Fault, which resulted in surface rupture during the Late Pleistocene-Holocene period.","PeriodicalId":49411,"journal":{"name":"Turkish Journal of Earth Sciences","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2023-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43740928","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Masoome Alaei, Alireza Nadimi, Homayon Safaei, M. Dehbozorgi
: Change in the steepness of river profiles caused by tectonic forces (uplift and material weakening in fault zones) causes the formation of the tectonically formed knickpoints (TFKs), which is an important geomorphic feature in bedrock river morphology. In this research, knickpoints in a wide area of the south of Central Alborz using the stream gradient (Gd) and the normalized steepness index (k sn ) were identified. According to the location of the knickpoints in relation to the faults in the area, the TFKs were identified. Analysis of the extracted TFKs with the longitudinal profile, logarithm slope-area plots, and natural logarithm gradient-distance plots confirmed their correspondence with the active segments of faults. Investigating the characteristics of TFKs such as length, height and gradient indicated that TFKs related to Mosha and North Tehran faults are high-altitude and the TFKs related to Taleghan and Eshtehard faults are long-distance. The identification of numerous TFKs on the active fault segments of the area and their confirmation based on field observations indicate a high rate of uplift and recent tectonic activity in the southern side of Central Alborz, which shows the importance of seismic studies due to the possibility of destructive earthquakes in the future.
{"title":"Evaluating the influence of recent tectonic activity on the river evolution using the identification of knickpoints in the south of Central Alborz Belt","authors":"Masoome Alaei, Alireza Nadimi, Homayon Safaei, M. Dehbozorgi","doi":"10.55730/1300-0985.1865","DOIUrl":"https://doi.org/10.55730/1300-0985.1865","url":null,"abstract":": Change in the steepness of river profiles caused by tectonic forces (uplift and material weakening in fault zones) causes the formation of the tectonically formed knickpoints (TFKs), which is an important geomorphic feature in bedrock river morphology. In this research, knickpoints in a wide area of the south of Central Alborz using the stream gradient (Gd) and the normalized steepness index (k sn ) were identified. According to the location of the knickpoints in relation to the faults in the area, the TFKs were identified. Analysis of the extracted TFKs with the longitudinal profile, logarithm slope-area plots, and natural logarithm gradient-distance plots confirmed their correspondence with the active segments of faults. Investigating the characteristics of TFKs such as length, height and gradient indicated that TFKs related to Mosha and North Tehran faults are high-altitude and the TFKs related to Taleghan and Eshtehard faults are long-distance. The identification of numerous TFKs on the active fault segments of the area and their confirmation based on field observations indicate a high rate of uplift and recent tectonic activity in the southern side of Central Alborz, which shows the importance of seismic studies due to the possibility of destructive earthquakes in the future.","PeriodicalId":49411,"journal":{"name":"Turkish Journal of Earth Sciences","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2023-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43635778","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
: Gravitational attraction of the Earth’s visible topography above the mean sea level is generally regarded as an unwanted signal in various geoscience applications. It should be removed from the observations to reveal the remaining signals of subsurface anomalous density distribution or to satisfy the boundary condition in solving the geodetic boundary value problems. However, the task of determining the gravimetric terrain effects involves tedious numerical computations when high‐resolution elevation data is used. While the traditional computational approach relies on flat-Earth approximation and neglects the topographic masses beyond some fixed integration radius, e.g., planar complete Bouguer correction, the modern methods apply spherical-Earth approximation and consider the far zone contribution, e.g., spherical complete Bouguer correction. This study compares the planar and spherical complete Bouguer corrections with constant topo-density at two test areas in Turkey, then assesses the performance of the recently released ultra-high resolution SRTM2gravity model in the same regions. Moreover, the first lateral global topographical density model (UNB_ TopoDens) has been employed to quantify the effect of topographic mass-density anomalies on gravity across the study areas. The numerical investigations have shown that simple planar complete Bouguer corrections exhibit similar spatial structure to those of the spherical counterparts, but with different magnitudes. There exists an average bias of around 30 mGal between the planar and spherical Bouguer correction because the latter takes the gravitational attraction of global topography into account. The SRTM2gravity model performs exceptionally well in the test regions and can directly be used to derive spherical Bouguer corrections over land areas with little computational effort. The topo-density anomalies may induce gravity effects up to 60 mGal, particularly over the mountainous parts of the study regions. This considerable amount of contribution should be treated carefully and cautiously especially in geodetic applications since the solution of geodetic boundary problems requires rigorous compensation of topographical gravity effects with actual density distribution. The results of the study are also hoped to give insights into the reproduction of the forthcoming regional Bouguer anomaly map of Turkey.
{"title":"Spherical Bouguer effect of topography on gravity with constant and laterally varying density","authors":"Mehmet Simav","doi":"10.55730/1300-0985.1868","DOIUrl":"https://doi.org/10.55730/1300-0985.1868","url":null,"abstract":": Gravitational attraction of the Earth’s visible topography above the mean sea level is generally regarded as an unwanted signal in various geoscience applications. It should be removed from the observations to reveal the remaining signals of subsurface anomalous density distribution or to satisfy the boundary condition in solving the geodetic boundary value problems. However, the task of determining the gravimetric terrain effects involves tedious numerical computations when high‐resolution elevation data is used. While the traditional computational approach relies on flat-Earth approximation and neglects the topographic masses beyond some fixed integration radius, e.g., planar complete Bouguer correction, the modern methods apply spherical-Earth approximation and consider the far zone contribution, e.g., spherical complete Bouguer correction. This study compares the planar and spherical complete Bouguer corrections with constant topo-density at two test areas in Turkey, then assesses the performance of the recently released ultra-high resolution SRTM2gravity model in the same regions. Moreover, the first lateral global topographical density model (UNB_ TopoDens) has been employed to quantify the effect of topographic mass-density anomalies on gravity across the study areas. The numerical investigations have shown that simple planar complete Bouguer corrections exhibit similar spatial structure to those of the spherical counterparts, but with different magnitudes. There exists an average bias of around 30 mGal between the planar and spherical Bouguer correction because the latter takes the gravitational attraction of global topography into account. The SRTM2gravity model performs exceptionally well in the test regions and can directly be used to derive spherical Bouguer corrections over land areas with little computational effort. The topo-density anomalies may induce gravity effects up to 60 mGal, particularly over the mountainous parts of the study regions. This considerable amount of contribution should be treated carefully and cautiously especially in geodetic applications since the solution of geodetic boundary problems requires rigorous compensation of topographical gravity effects with actual density distribution. The results of the study are also hoped to give insights into the reproduction of the forthcoming regional Bouguer anomaly map of Turkey.","PeriodicalId":49411,"journal":{"name":"Turkish Journal of Earth Sciences","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2023-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46917772","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lahcen Rerbal, Boualem Bouyahiaoui, Abbas Marok, A. Abtout, H. Boukerbout, Kamar Eddine Bensefia
: In order to refine the geological mapping and to improve our knowledge of the Tlemcen Mountains structure (northwestern Algeria), the interpretation of aeromagnetic data using several processing techniques allowed us to map the Paleozoic basement of Rhar Roubane Mountains and the sedimentary cover constituted by geological formations of Mesozoic and Cenozoic age. Structurally, the Tlemcen Mountains are formed by several structures (e.g., Sebdou Graben), separated by three major transverse faults NNE-SSW (Tafna-Magoura, Oued Chouly and Aïn Tellout transverse faults). We have also been able to highlight a set of deep and shallower structures, trending mainly in NE-SW, N-S, and E-W, and affect the western part of the Tlemcen Mountains (Rhar Roubane Horst) and the south-eastern part of the Tlemcen Mountains.
{"title":"Use of aeromagnetic data for structural mapping of the Tlemcen Mountains (northwestern Algeria)","authors":"Lahcen Rerbal, Boualem Bouyahiaoui, Abbas Marok, A. Abtout, H. Boukerbout, Kamar Eddine Bensefia","doi":"10.55730/1300-0985.1867","DOIUrl":"https://doi.org/10.55730/1300-0985.1867","url":null,"abstract":": In order to refine the geological mapping and to improve our knowledge of the Tlemcen Mountains structure (northwestern Algeria), the interpretation of aeromagnetic data using several processing techniques allowed us to map the Paleozoic basement of Rhar Roubane Mountains and the sedimentary cover constituted by geological formations of Mesozoic and Cenozoic age. Structurally, the Tlemcen Mountains are formed by several structures (e.g., Sebdou Graben), separated by three major transverse faults NNE-SSW (Tafna-Magoura, Oued Chouly and Aïn Tellout transverse faults). We have also been able to highlight a set of deep and shallower structures, trending mainly in NE-SW, N-S, and E-W, and affect the western part of the Tlemcen Mountains (Rhar Roubane Horst) and the south-eastern part of the Tlemcen Mountains.","PeriodicalId":49411,"journal":{"name":"Turkish Journal of Earth Sciences","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2023-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49472573","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
: 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.
{"title":"Pithonellid calcitarch record in the middle? Cenomanian Derdere-A Member, SE Turkey: palaeoenvironmental changes and stratigraphic significance","authors":"O. Mülayim, İ. Yılmaz, B. Ferré","doi":"10.55730/1300-0985.1827","DOIUrl":"https://doi.org/10.55730/1300-0985.1827","url":null,"abstract":": 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.","PeriodicalId":49411,"journal":{"name":"Turkish Journal of Earth Sciences","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48955517","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
: 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 δ 18 O and δ 2 D 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.
{"title":"Hydrogeochemical pattern and environmental isotope hydrology of coastal Bademli geothermal area (BGA) in western Turkey (Dikili-İzmir): A new geothermal prospect","authors":"Adi̇le Meli̇s Somay Altaş, Ü. Gemici","doi":"10.55730/1300-0985.1830","DOIUrl":"https://doi.org/10.55730/1300-0985.1830","url":null,"abstract":": 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 δ 18 O and δ 2 D 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.","PeriodicalId":49411,"journal":{"name":"Turkish Journal of Earth Sciences","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41280856","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Panagiotis Skandalos, Koen Lansing, F. A. Demirel, M. C. Alçiçek, Serdar Mayda, F. Dieleman, L. W. H. Ostende
: 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.
{"title":"Early Pliocene Arvicolinae and Cricetinae from the locality of Afşar, western Turkey","authors":"Panagiotis Skandalos, Koen Lansing, F. A. Demirel, M. C. Alçiçek, Serdar Mayda, F. Dieleman, L. W. H. Ostende","doi":"10.55730/1300-0985.1826","DOIUrl":"https://doi.org/10.55730/1300-0985.1826","url":null,"abstract":": 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.","PeriodicalId":49411,"journal":{"name":"Turkish Journal of Earth Sciences","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47944818","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
: The development of carbon capture and storage techniques has become essential to reduce and mitigating CO 2 emissions to the atmosphere. CarbFix1 and CarbFix2 projects carried out in Iceland demonstrated that the emissions of waste CO 2 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-CO 2 interactions prevent the mineralization of CO 2 in the reservoir. This outcome differs from CarbFix projects in terms of the carbonization process, but the CO 2 injection is still reliable with solubility-trapping in a geothermal reservoir to partially mitigate the emission. Roughly, 200 kt of CO 2 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.
{"title":"Update for reactive transport modeling of the Kızıldere geothermal field to reduce uncertainties in the early inspections","authors":"Selçuk Erol, T. Akın, S. Akin","doi":"10.55730/1300-0985.1860","DOIUrl":"https://doi.org/10.55730/1300-0985.1860","url":null,"abstract":": The development of carbon capture and storage techniques has become essential to reduce and mitigating CO 2 emissions to the atmosphere. CarbFix1 and CarbFix2 projects carried out in Iceland demonstrated that the emissions of waste CO 2 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-CO 2 interactions prevent the mineralization of CO 2 in the reservoir. This outcome differs from CarbFix projects in terms of the carbonization process, but the CO 2 injection is still reliable with solubility-trapping in a geothermal reservoir to partially mitigate the emission. Roughly, 200 kt of CO 2 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.","PeriodicalId":49411,"journal":{"name":"Turkish Journal of Earth Sciences","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46835819","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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