: The Almacık Complex is a tectonic unit of high-grade metamorphic rocks in the Intra-Pontide Suture Zone in northwest Turkey. It consists mainly of amphibolite, metaultramafic rock, and gneiss, which are intruded by numerous pre-, syn-, and posttectonic felsic veins. The Almacık Complex is variously interpreted as a Cretaceous or Neoproterozoic ophiolite, or a Permian mafic-ultramafic complex representing the middle to lower crust of the Sakarya Zone. Herein, new petrological and geochronological data were presented from the Almacık Complex. Two-pyroxene geothermometry in the metawebsterites indicated that the Almacık Complex has undergone upper amphibolite-facies metamorphism at 750 ± 30 °C and 8 ± 4 kbar. U-Pb zircon and Ar-Ar ages from 11 samples indicate the presence of late Neoproterozoic, Permian, and Jurassic thermal events. Most of the Almacık Complex consists of late Neoproterozoic amphibolites and gneisses, representing the basement of the İstanbul Zone. This basement was intruded by voluminous mafic magma during the Late Permian. The basement and the Permian ultramafic-mafic rocks subsequently underwent upper amphibolite-facies metamorphism during the Jurassic, possibly at the base of a magmatic arc.
:阿尔马茨克复合体是土耳其西北部内蓬莱断裂带上的一个高级变质岩构造单元。它主要由闪长岩、辉绿岩和片麻岩组成，并被许多构造前、同步和构造后长石脉所侵入。人们对阿尔马克复合岩有不同的解释，认为它是白垩纪或新新生代的蛇绿岩，或者是代表萨卡里亚区中下地壳的二叠纪黑云母-超黑云母复合岩。本文介绍了来自阿尔马溪克复合岩的新岩石学和地质年代数据。偏闪长岩中的双辉石测地温度表明，阿尔马溪克岩群在 750 ± 30 °C 和 8 ± 4 千巴的温度下经历了上闪长岩层变质作用。从11个样本中提取的U-Pb锆石和Ar-Ar年龄显示出新新生代晚期、二叠纪和侏罗纪热事件的存在。阿尔马克岩群的大部分由新新生代晚期的闪长岩和片麻岩组成，是伊斯坦布尔区的基底。二叠纪晚期，大量岩浆侵入了这一基底。基底和二叠纪超闪长岩-黑云母岩随后在侏罗纪期间经历了上闪长岩-变质作用，可能是在岩浆弧的底部。
{"title":"Almacık Complex-an exhumed lower to middle crust in northwest Anatolia","authors":"A. Okay, A. Kylander-Clark, Sarah Sherlock","doi":"10.55730/1300-0985.1878","DOIUrl":"https://doi.org/10.55730/1300-0985.1878","url":null,"abstract":": The Almacık Complex is a tectonic unit of high-grade metamorphic rocks in the Intra-Pontide Suture Zone in northwest Turkey. It consists mainly of amphibolite, metaultramafic rock, and gneiss, which are intruded by numerous pre-, syn-, and posttectonic felsic veins. The Almacık Complex is variously interpreted as a Cretaceous or Neoproterozoic ophiolite, or a Permian mafic-ultramafic complex representing the middle to lower crust of the Sakarya Zone. Herein, new petrological and geochronological data were presented from the Almacık Complex. Two-pyroxene geothermometry in the metawebsterites indicated that the Almacık Complex has undergone upper amphibolite-facies metamorphism at 750 ± 30 °C and 8 ± 4 kbar. U-Pb zircon and Ar-Ar ages from 11 samples indicate the presence of late Neoproterozoic, Permian, and Jurassic thermal events. Most of the Almacık Complex consists of late Neoproterozoic amphibolites and gneisses, representing the basement of the İstanbul Zone. This basement was intruded by voluminous mafic magma during the Late Permian. The basement and the Permian ultramafic-mafic rocks subsequently underwent upper amphibolite-facies metamorphism during the Jurassic, possibly at the base of a magmatic arc.","PeriodicalId":49411,"journal":{"name":"Turkish Journal of Earth Sciences","volume":"35 4","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139264445","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}
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 3 He/4 He ratios well above that of Air Saturated Waters (ASW = 1.39 × 10-6) clearly indicating a significant contribution of 3 He 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.
{"title":"Isotope and hydrochemical characteristics of thermal waters along the active fault zone (Erzin-Hatay/Turkey) and their geothermal potential","authors":"DİDEM YASİN, GALİP YÜCE","doi":"10.55730/1300-0985.1871","DOIUrl":"https://doi.org/10.55730/1300-0985.1871","url":null,"abstract":"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 3 He/4 He ratios well above that of Air Saturated Waters (ASW = 1.39 × 10-6) clearly indicating a significant contribution of 3 He 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.","PeriodicalId":49411,"journal":{"name":"Turkish Journal of Earth Sciences","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135246520","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}
MEHMET FURKAN ŞENER, MUHAMMED ZEYNEL ÖZTÜRK, ALPER BABA
Türkiye is located in the Mediterranean sector of the Alpine-Himalayan tectonic belt and is among the foremost seven countries in the world having an abundance of geothermal resources. The Central Anatolian Crystalline Complex (CACC) is one of the most important geothermal regions in Türkiye. This study aims to evaluate the geothermal system of CACC using the geological, structural, and hydrogeochemical properties that were obtained from previous studies. The present study investigated and evaluated the hydrogeochemical and isotopic properties of 762 water samples belonging to 45 different localities from 41 scientific studies. The result shows that CACC has different heat sources and different hydrogeochemical processes. Major element chemistry of the water reveals that the geothermal fluids are mostly of the Ca - Mg - HCO3 , Na - Cl - HCO3 , and Ca-Cl water types. Silica geothermometers suggest that the reservoir temperature ranges from 48 to 180 °C. Based on the δ18O - δD relationship, water samples have a high-altitude meteoric origin. Stable isotopic data indicate that the geothermal fluids are formed by local recharge and deep circulation of meteoric waters.
{"title":"A review of the geothermal system evolution and distribution in the Central Anatolian Crystalline Complex (Türkiye)","authors":"MEHMET FURKAN ŞENER, MUHAMMED ZEYNEL ÖZTÜRK, ALPER BABA","doi":"10.55730/1300-0985.1870","DOIUrl":"https://doi.org/10.55730/1300-0985.1870","url":null,"abstract":"Türkiye is located in the Mediterranean sector of the Alpine-Himalayan tectonic belt and is among the foremost seven countries in the world having an abundance of geothermal resources. The Central Anatolian Crystalline Complex (CACC) is one of the most important geothermal regions in Türkiye. This study aims to evaluate the geothermal system of CACC using the geological, structural, and hydrogeochemical properties that were obtained from previous studies. The present study investigated and evaluated the hydrogeochemical and isotopic properties of 762 water samples belonging to 45 different localities from 41 scientific studies. The result shows that CACC has different heat sources and different hydrogeochemical processes. Major element chemistry of the water reveals that the geothermal fluids are mostly of the Ca - Mg - HCO3 , Na - Cl - HCO3 , and Ca-Cl water types. Silica geothermometers suggest that the reservoir temperature ranges from 48 to 180 °C. Based on the δ18O - δD relationship, water samples have a high-altitude meteoric origin. Stable isotopic data indicate that the geothermal fluids are formed by local recharge and deep circulation of meteoric waters.","PeriodicalId":49411,"journal":{"name":"Turkish Journal of Earth Sciences","volume":"132 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135246518","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}
Hai-Zhen Wei, Martin Palmer, Jun-Lin Wang, Shao-Yong Jiang, Simon V. Hohl, Yuan-Feng Zhu, Chun Huan, Miao-Miao Zhang, YEŞİM YÜCEL ÖZTÜRK
Borax, ulexite, and colemanite minerals are by far the most important economic source of boron and occur almost exclusively in nonmarine evaporite deposits. While much is known about the geological setting in which they are found, surprisingly little is known about the chemical and physical properties of the brines from which they are formed. Oxygen isotope studies have the potential to reveal important new information regarding borate formation, but unlike most other common oxygen-bearing salts precipitated from brines, there are no experimental data regarding the oxygen isotope fractionation factors between borates and brines. As a first attempt to address this gap in our understanding we have determined Δ18Oborate-water values between 0 and 100 °C using density functional theory calculations (DFT). These results predicted Δ18Oborate-water values of 12.87, 22.32, and 17.5 at 25 °C for borax, colemanite and ulexite, respectively.
{"title":"Density functional theory calculations of equilibrium oxygen isotope fractionation between borate minerals and aqueous fluids","authors":"Hai-Zhen Wei, Martin Palmer, Jun-Lin Wang, Shao-Yong Jiang, Simon V. Hohl, Yuan-Feng Zhu, Chun Huan, Miao-Miao Zhang, YEŞİM YÜCEL ÖZTÜRK","doi":"10.55730/1300-0985.1873","DOIUrl":"https://doi.org/10.55730/1300-0985.1873","url":null,"abstract":"Borax, ulexite, and colemanite minerals are by far the most important economic source of boron and occur almost exclusively in nonmarine evaporite deposits. While much is known about the geological setting in which they are found, surprisingly little is known about the chemical and physical properties of the brines from which they are formed. Oxygen isotope studies have the potential to reveal important new information regarding borate formation, but unlike most other common oxygen-bearing salts precipitated from brines, there are no experimental data regarding the oxygen isotope fractionation factors between borates and brines. As a first attempt to address this gap in our understanding we have determined Δ18Oborate-water values between 0 and 100 °C using density functional theory calculations (DFT). These results predicted Δ18Oborate-water values of 12.87, 22.32, and 17.5 at 25 °C for borax, colemanite and ulexite, respectively.","PeriodicalId":49411,"journal":{"name":"Turkish Journal of Earth Sciences","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135246523","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}
Carboniferous bituminous coals of the Zonguldak Basin have been mined for over a century. Due to underground mining activity, there have been several fatal incidents related to gas explosions. The gas content of the coals varies greatly in the basin mainly based on coal maturity (rank), increasing with increasing coal depth. In this study, we report a map for coal depth and coal rank in the Kozlu-Üzülmez-Karadon districts of Zonguldak Basin with hope the that it would aid coal gas exploration/exploitation and also coal gas degassing efforts for safer underground mining production in the Zonguldak Basin.
{"title":"Rank of Kozlu Formation coals in the Zonguldak Basin: implications for coalbed gas","authors":"MEHMET NAMIK YALÇIN, CEMİL SEYİS, SEDAT İNAN","doi":"10.55730/1300-0985.1875","DOIUrl":"https://doi.org/10.55730/1300-0985.1875","url":null,"abstract":"Carboniferous bituminous coals of the Zonguldak Basin have been mined for over a century. Due to underground mining activity, there have been several fatal incidents related to gas explosions. The gas content of the coals varies greatly in the basin mainly based on coal maturity (rank), increasing with increasing coal depth. In this study, we report a map for coal depth and coal rank in the Kozlu-Üzülmez-Karadon districts of Zonguldak Basin with hope the that it would aid coal gas exploration/exploitation and also coal gas degassing efforts for safer underground mining production in the Zonguldak Basin.","PeriodicalId":49411,"journal":{"name":"Turkish Journal of Earth Sciences","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135246519","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}
GÖKHAN ASLAN, Marcello de MICHELE, Daniel RAUCOULES, François RENARD, John DEHLS, Ivanna PENNA, Reginald HERMANNS, ZİYADİN ÇAKIR
We report here a slow-moving landslide complex of the lateral spreading type revealed by Sentinel-1 interferometric timeseries analysis. Located along the western coast of the Aral Sea, with a >150-km length and 3-km width, a giant active landslide complex, slides with a constant velocity of up to 60 mm/year. Systematic subsidence up to 5 mm/year is also observed along narrow strips of terraces that appear to result from rotations of fault-bounded blocks. The landslide deformation velocity does not correlate with the annual variations of the water level in the southwestern lake of the Aral Sea during the observation period of 2014-2022, indicating a long-term forcing of this landslide that is rather interpreted to be caused by the long-term sea-level drop. The lateral spreading involves the competent limestone beds lying horizontally on plastic clay- and evaporite-rich layers. We propose a conceptual model for the kinematic of landslides that appear to be controlled by the attitude of bedding, lithological sequence, hydrogeology, and low angle faults.
{"title":"Dynamics of a giant slow landslide complex along the coast of the Aral Sea, Central Asia","authors":"GÖKHAN ASLAN, Marcello de MICHELE, Daniel RAUCOULES, François RENARD, John DEHLS, Ivanna PENNA, Reginald HERMANNS, ZİYADİN ÇAKIR","doi":"10.55730/1300-0985.1876","DOIUrl":"https://doi.org/10.55730/1300-0985.1876","url":null,"abstract":"We report here a slow-moving landslide complex of the lateral spreading type revealed by Sentinel-1 interferometric timeseries analysis. Located along the western coast of the Aral Sea, with a >150-km length and 3-km width, a giant active landslide complex, slides with a constant velocity of up to 60 mm/year. Systematic subsidence up to 5 mm/year is also observed along narrow strips of terraces that appear to result from rotations of fault-bounded blocks. The landslide deformation velocity does not correlate with the annual variations of the water level in the southwestern lake of the Aral Sea during the observation period of 2014-2022, indicating a long-term forcing of this landslide that is rather interpreted to be caused by the long-term sea-level drop. The lateral spreading involves the competent limestone beds lying horizontally on plastic clay- and evaporite-rich layers. We propose a conceptual model for the kinematic of landslides that appear to be controlled by the attitude of bedding, lithological sequence, hydrogeology, and low angle faults.","PeriodicalId":49411,"journal":{"name":"Turkish Journal of Earth Sciences","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135246524","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 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 , Fe2 O3 , 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 H2 S-
{"title":"Mineralogical-petrographical features, geochemical characteristics, and S isotope variability of Pb-Zn deposits in the Sakarya fragment of the Biga Peninsula (NW Türkiye)","authors":"GÖKHAN DEMİRELA, SİNAN AKISKA, ELİF AKISKA","doi":"10.55730/1300-0985.1874","DOIUrl":"https://doi.org/10.55730/1300-0985.1874","url":null,"abstract":"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 , Fe2 O3 , 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 H2 S-","PeriodicalId":49411,"journal":{"name":"Turkish Journal of Earth Sciences","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135246667","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}
Zircon morphology parameters reflect the physicochemical conditions during crystallization and can be modified by different processes. Zircon populations from Miocene-Pliocene ignimbrites of the Central Anatolian Volcanic Province (CAVP) were studied to reveal relations between the external morphology of zircons and petrogenetic processes. Descriptive grain shape parameters (e.g., minor and major axes, area, perimeter, aspect ratio, roundness, and circularity) were automatically measured from transmitted light images of zircons by a graphical application called AnalyZr. Principal component and cluster analysis were used to determine potential shape descriptors (perimeter, major and minor axis length, and maximum and minimum Feret) for characterizing grains from a particular rock. Accordingly, zircons from ignimbrites display morphological variations, which can be attributed to a specific magmatic process. Zircon isotopic compositions from previous studies indicate that ignimbrites are derived from mantle sources, but due to the distinct contributions of crustal components and periodic mafic recharge, isotopic heterogeneity occurs in the genesis of the ignimbrites. Furthermore, the typological evolution of zircons has already revealed that even a small decrease in saturation and crystallization temperature can significantly alter the external morphology of zircons. The clear imprint of hybridization in the zircon morphology of CAVP ignimbrites might provide information about the development of zircon within silicic melts. This study offers new insight into the integration of data on shape and isotope variations in zircon populations that can be traced back to the magmatic controls on zircon crystal growth.
{"title":"Zircon grain shape parameters from ignimbrites of the Central Anatolian Volcanic Province (CAVP) with implications for petrogenetic processes","authors":"LÜTFİYE AKIN","doi":"10.55730/1300-0985.1872","DOIUrl":"https://doi.org/10.55730/1300-0985.1872","url":null,"abstract":"Zircon morphology parameters reflect the physicochemical conditions during crystallization and can be modified by different processes. Zircon populations from Miocene-Pliocene ignimbrites of the Central Anatolian Volcanic Province (CAVP) were studied to reveal relations between the external morphology of zircons and petrogenetic processes. Descriptive grain shape parameters (e.g., minor and major axes, area, perimeter, aspect ratio, roundness, and circularity) were automatically measured from transmitted light images of zircons by a graphical application called AnalyZr. Principal component and cluster analysis were used to determine potential shape descriptors (perimeter, major and minor axis length, and maximum and minimum Feret) for characterizing grains from a particular rock. Accordingly, zircons from ignimbrites display morphological variations, which can be attributed to a specific magmatic process. Zircon isotopic compositions from previous studies indicate that ignimbrites are derived from mantle sources, but due to the distinct contributions of crustal components and periodic mafic recharge, isotopic heterogeneity occurs in the genesis of the ignimbrites. Furthermore, the typological evolution of zircons has already revealed that even a small decrease in saturation and crystallization temperature can significantly alter the external morphology of zircons. The clear imprint of hybridization in the zircon morphology of CAVP ignimbrites might provide information about the development of zircon within silicic melts. This study offers new insight into the integration of data on shape and isotope variations in zircon populations that can be traced back to the magmatic controls on zircon crystal growth.","PeriodicalId":49411,"journal":{"name":"Turkish Journal of Earth Sciences","volume":"69 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135246522","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}
: 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":" ","pages":""},"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":" ","pages":""},"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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：