Central Anatolian Plateau (CAP) is the only orogenic plateau in the Mediterranean collision zone ... more Central Anatolian Plateau (CAP) is the only orogenic plateau in the Mediterranean collision zone that can be compared to the evolution of its larger counterparts such as Tibet, the North American Cordilleran Plateau or the Andean Altiplano-Puna. Tuz Gölü Basin (TGB) is located in the middle of CAP and the dominant tectonic regime is extension with active normal faults. TGB is represented by a thick lacustrine sequence made up of evaporites, limestones, conglomerates, cross-bedded sandstones and mudstones with ignimbritic levels that unconformably cover the pre-Miocene basement units. Active normal faults represent a common feature within many orogens, and the negative tectonic inversion (a transition from contraction to extension) occurs often during the advanced stages of uplift. Tuz Gölü Fault, which is a normal fault with a dextral strike-slip component, bounds the TGB at the east. Our preliminary fault-slip data collected from the fault surfaces and kinematic analyses results show parallel normal faults and the tilting of the key-levels indicate that there is a graben formation due to a NE-SW extension within the area. To state the relationship between the extensional tectonics within a plateau and the formation and evolution of the plateau, the uplift rates by using structural data such as kinematic analyzes of the faults and tilting of the strata and ancient shorelines due to normal faulting will be calculated. Additionally, dating the ignimbrites in the basin using radiometric techniques will help to determine the initiation age of the normal faulting, which is one of the key observations that helps to understand the evolution of the plateau. This presentation was supported by the EUROCORES programme TOPO-EUROPE of the European Science Foundation.
The timing of exhumation of high-grade metamorphic rocks and granitoids of the Nigde dome, in sou... more The timing of exhumation of high-grade metamorphic rocks and granitoids of the Nigde dome, in southern Central Anatolia, is a matter of debate. Our investigations show that the Nigde metamorphics must have reached the surface before the Eocene, as a sedimentary sequence of earliest Eocene to Middle Eocene age nonconformably overlies the high-grade rocks of the dome, and reworks them as pebbles. In contrast, Maastrichtian-Late Palaeocene sediments lie against the dome through a series of low-angle faults. These deposits are devoid of clasts originating from the high-grade rocks, suggesting that the Nigde metamorphics did not reach the surface before Late Palaeocene times. Structural analysis documents the existence of an extensional detachment at the top of the Nigde dome, superposing a superficial unit made up of massive ophiolitic rocks onto the high-grade metamorphics. Top-to-northeast pervasive shearing in the footwall becomes localized in a 100 m-thick zone of mylonites beneath the ophiolites, the contact itself being underlined by an irregular array of cataclasites. Synfolial muscovites from a gneiss within the mylonitic shear zone give a 40Ar/39Ar age of 76 Ma. 40Ar/39Ar dating on hornblendes from pervasively foliated amphibolites further below gives an isochron age of 79 Ma. From these results we deduce a mean cooling rate of about 60^oC/My during the transition from pervasive to localized ductile shearing associated with extension. Various granitoids have intruded the metamorphic footwall during top-to-northeast shearing. A two-micas granite is locally exposed in the northwestern part of the dome, showing pervasive C-S fabrics, which attests for its syn-kinematic emplacement. Muscovites from this granite give a plateau age of 78 Ma. Further south and east, the Uckapili granite represents a late-kinematic intrusion, showing only locally, at its roof, the development of C-S fabrics. For this granite, 40Ar/39Ar dating on muscovites and biotites gives plateau ages of 76 and 75 Ma, respectively. Altogether, the new 40Ar/39Ar data indicate that extensional exhumation of the Nigde dome was active during the Campanian, while field relations suggest that progressive unroofing beneath a northeast-dipping extensional detachment went on until Late Palaeocene times.
The E-W trending Reşadiye peninsula located at the southwestern part of the Anatolian Plate is an... more The E-W trending Reşadiye peninsula located at the southwestern part of the Anatolian Plate is an important horst developed between Gökova and Hisarönü Grabens. NW-trending the Datça Graben is the prominent structure comprising on the Reşadiye peninsula and records the significant fingerprints of palaeogeographical and kinematical characteristics from Pliocene to recent. The Datça Graben is controlled by NW-trending the Karaköy fault in the south and E-W trending the Kızlan fault in the north. Basement rocks of the graben are composed of ophiolitic rocks of the Lycian Nappes and Jurassic marine carbonates. The basinfill initiates with Early Pliocene Kızılaǧaç formation consisting conglomerates and continues with transgressive sequence (Yıldırımlı formation) composed of conglomerates, sandstones and marls with ignimbrite intercalations. Late Pliocene age was attributed to this formation based on the gastropoda and pelecypoda fauna according to previous studies. These units are unconf...
Hacettepe University Bulletin of Natural Sciences and Engineering Series B: Mathematics and Statistics
06800 Beytepe, ANKARA Geliş (received) : 18 Mayıs (May) 2011 Kabul (accepted) : 27 Haziran (June)... more 06800 Beytepe, ANKARA Geliş (received) : 18 Mayıs (May) 2011 Kabul (accepted) : 27 Haziran (June) 2011 ÖZ Miyosen Aksu Havzası, Afrika-Avrasya dalma batma zonunda, Anadolu yarımadasının güneyinde yer alan bir önül-ke (foreland) havzasıdır. Sığ denizel kırıntılılar ve karbonatlar ile karasal birimlerden oluşan havza çökel dolgusun-da, kaba taneli yelpaze deltası çökelleri önemli bir yere sahiptir. Bu çalışmada, Tortoniyen'de havzanın batı kena-rında depolanan, Kargı Yelpaze Deltası'nın yapısal ve sedimantolojik özellikleri incelenmiş, yelpaze deltasının geli-şimi tektonizma ve deniz seviyesi oynamaları bakımından değerlendirilmiştir. Farklı seviyelerinde yama resifleri bu-lunan kaba taneli yelpaze deltası istifi, fasiyes özellikleri, çökelme süreçleri ve çökelme alt ortamları (alüvyon yelpa-zesi, kıyı-lagün, delta önü) bakımından incelendiğinde, yelpaze deltasının hem regresif hem de transgresif gelişim gösterdiği görülmektedir. Ardalanmalı şekilde bulunan karasal ve sığ deni...
ABSTRACT The Aksu Basin, within the Isparta Angle, is located to the north of the intersection of... more ABSTRACT The Aksu Basin, within the Isparta Angle, is located to the north of the intersection of the Aegean and Cyprus arcs and has been evolving since the Middle Miocene. Correlation of: (1) kinematic analysis of fault planes that cut the basin fill, (2) the reactivation/inversion of fault planes and (3) sedimentological data indicate that the Aksu Basin has evolved by four alternating compressional and extensional tectonic phases since its formation. The first phase was NW-SE oriented compression caused by the emplacement of the Lycian Nappes which ended in Langhian. This compressional phase that induced the formation and the initial deformation of the basin was followed by a NW-SE extensional phase. This tectonic phase prevailed between the Langhian and Messinian and was terminated by a NE-SW compressional regime known as the Aksu Phase. The neotectonic period is characterized by NE-SW extension and began in the Late Pliocene. Correlation with the existing tectonic literature shows that the order of deformational phases proposed in this study might also be valid for the entire Isparta Angle area.
The timing of exhumation of high-grade metamorphic rocks and granitoids of the Nigde dome, in sou... more The timing of exhumation of high-grade metamorphic rocks and granitoids of the Nigde dome, in southern Central Anatolia, is a matter of debate. Our investigations show that the Nigde metamorphics must have reached the surface before the Eocene, as a sedimentary sequence of earliest Eocene to Middle Eocene age nonconformably overlies the high-grade rocks of the dome, and reworks them as pebbles. In contrast, Maastrichtian-Late Palaeocene sediments lie against the dome through a series of low-angle faults. These deposits are devoid of clasts originating from the high-grade rocks, suggesting that the Nigde metamorphics did not reach the surface before Late Palaeocene times. Structural analysis documents the existence of an extensional detachment at the top of the Nigde dome, superposing a superficial unit made up of massive ophiolitic rocks onto the high-grade metamorphics. Top-to-northeast pervasive shearing in the footwall becomes localized in a 100 m-thick zone of mylonites beneath ...
The present study highlights the hydrogeological and hydrogeochemical characteristics of the CO2-... more The present study highlights the hydrogeological and hydrogeochemical characteristics of the CO2-rich thermal–mineral waters in Kayseri, Turkey. These waters of Dokuzpınar cold spring (DPS) (12–13°C), Yeşilhisar mineral spring (YMS) (13–16°C), Acısu mineral spring (ACMS) (20–22.5°C), Tekgöz thermal spring (TGS) (40–41°C), and Bayramhacı thermal-mineral spring (BTMS) (45–46.5°C) have different physical and chemical compositions. The waters are located within the Erciyes basin in the Central Anatolian Crystalline complex consisting of three main rock units. Metamorphic/crystalline rocks occur as the basement, sedimentary rocks of Upper Cretaceous-Quaternary age form the cover, and volcanosedimentary rocks Miocene-Quaternary in age represent the extrusive products of magmatism acting in that period. All these units are covered unconformably by terrace and alluvial deposits, and travertine occurrences have variable permeability. Dokuzpinar cold spring, YMS and ACMS localized mainly along the faults within the region have higher Na+ and Cl− contents whereas TGS and BTMS have higher amounts of Ca2+ and HCO 3−. The high concentrations of Ca2+ and HCO 3− are mainly related to the high CO2 contents resulting from interactions with carbonate rocks. Whereas the high Na+ content is derived from the alkaline rocks, such as syenite, tuff and basalts, the Cl− is generally connected to the dissolution of the evaporitic sequences. These waters are of meteoric-type. BTMS deviates from meteoric water line. The content is related to the increases in the δ18O compositions due to mineral–water interaction (re-equilibrium) process. CO2-dominated YMS and ACMS with low temperatures have higher mineralizations. Yeşilhisar mineral spring, ACMS, TGS and BTMS are oversaturated in terms of calcite, aragonite, dolomite, goethite and hematite, and undersaturated with respect to gypsum, halite and anhydrite. Yeşilhisar mineral spring, ACMS and BTMS are also characterized by recent travertine precipitation. Dokuzpınar cold spring is undersaturated in terms of the above minerals. The higher ratios of Ca/Mg and Cl/HCO3, and lower ratios of SO4/Cl in BTMS than TGS suggest that TGS has shallow circulation compared to BTMS, and/or has much more heat-loss enroute the surface. The sequence of hydrogeochemical and isotopic compositions of the waters is in an order of DPS>YMS>ACMS>TGS>BTMS and this suggests a transition period from a shallow circulation to a deep circulation path.
Human activities and agriculture have had direct and indirect effects on the rates of contaminati... more Human activities and agriculture have had direct and indirect effects on the rates of contamination of groundwater in the Incesu-Dokuzpınar spring area. Direct effects include dissolution and transport of excess quantities of fertilizers with associated materials and hydrological alterations related to irrigation and drainage. Indirect effects may include changes in water–rock reactions in soils and aquifers caused by increased concentrations of dissolved oxidants, protons, and major ions. Agricultural activities have directly or indirectly affected the concentrations of a large number of inorganic chemicals in groundwater, for example NO3, N2, Cl, SO42, H+, K, Mg, Ca, Fe, Cu, B, Pb, and Zn, as well as a wide variety of pesticides and other organic compounds. For reactive contaminants like NO3, it is recommended that a combination of hydrochemical and environmental-tracer analytical approaches might be required to resolve changing inputs from subsequent alterations as causes of concentration gradients in groundwater. The water type of Dokuzpınar springs is mainly Na–Mg–Ca–Cl–HCO3. Note that the water types of the springs were directly related to the hydrogeochemical properties of outcrops at the study area. Thus, the high concentration of Ca2+ and HCO3 is mainly related to the high CO2 contents in the marbles, whereas the high Na concentration arises from the existing syenite, volcanic ash, basalt, and clay units, although the İncesu-Dokuzpınar springs cover most of the drinking and irrigation water demands of this area. The high concentrations of NO3 and NaCl show that the area around the springs is continuously being contaminated by untreated sewage and agricultural wastes, especially during dry periods. Therefore, this approach is based on the vulnerability studies of the catchment area, determination of the transfer time of the pollutant, and the water-bearing formations of İncesu-Dokuzpınar springs. Vulnerability in this study is defined as the intrinsic hydrogeochemical characteristics of an aquifer, which may show the sensitivity of groundwater to be contaminated by different human activities.
Central Anatolian Plateau (CAP) is the only orogenic plateau in the Mediterranean collision zone ... more Central Anatolian Plateau (CAP) is the only orogenic plateau in the Mediterranean collision zone that can be compared to the evolution of its larger counterparts such as Tibet, the North American Cordilleran Plateau or the Andean Altiplano-Puna. Tuz Gölü Basin (TGB) is located in the middle of CAP and the dominant tectonic regime is extension with active normal faults. TGB is represented by a thick lacustrine sequence made up of evaporites, limestones, conglomerates, cross-bedded sandstones and mudstones with ignimbritic levels that unconformably cover the pre-Miocene basement units. Active normal faults represent a common feature within many orogens, and the negative tectonic inversion (a transition from contraction to extension) occurs often during the advanced stages of uplift. Tuz Gölü Fault, which is a normal fault with a dextral strike-slip component, bounds the TGB at the east. Our preliminary fault-slip data collected from the fault surfaces and kinematic analyses results show parallel normal faults and the tilting of the key-levels indicate that there is a graben formation due to a NE-SW extension within the area. To state the relationship between the extensional tectonics within a plateau and the formation and evolution of the plateau, the uplift rates by using structural data such as kinematic analyzes of the faults and tilting of the strata and ancient shorelines due to normal faulting will be calculated. Additionally, dating the ignimbrites in the basin using radiometric techniques will help to determine the initiation age of the normal faulting, which is one of the key observations that helps to understand the evolution of the plateau. This presentation was supported by the EUROCORES programme TOPO-EUROPE of the European Science Foundation.
The timing of exhumation of high-grade metamorphic rocks and granitoids of the Nigde dome, in sou... more The timing of exhumation of high-grade metamorphic rocks and granitoids of the Nigde dome, in southern Central Anatolia, is a matter of debate. Our investigations show that the Nigde metamorphics must have reached the surface before the Eocene, as a sedimentary sequence of earliest Eocene to Middle Eocene age nonconformably overlies the high-grade rocks of the dome, and reworks them as pebbles. In contrast, Maastrichtian-Late Palaeocene sediments lie against the dome through a series of low-angle faults. These deposits are devoid of clasts originating from the high-grade rocks, suggesting that the Nigde metamorphics did not reach the surface before Late Palaeocene times. Structural analysis documents the existence of an extensional detachment at the top of the Nigde dome, superposing a superficial unit made up of massive ophiolitic rocks onto the high-grade metamorphics. Top-to-northeast pervasive shearing in the footwall becomes localized in a 100 m-thick zone of mylonites beneath the ophiolites, the contact itself being underlined by an irregular array of cataclasites. Synfolial muscovites from a gneiss within the mylonitic shear zone give a 40Ar/39Ar age of 76 Ma. 40Ar/39Ar dating on hornblendes from pervasively foliated amphibolites further below gives an isochron age of 79 Ma. From these results we deduce a mean cooling rate of about 60^oC/My during the transition from pervasive to localized ductile shearing associated with extension. Various granitoids have intruded the metamorphic footwall during top-to-northeast shearing. A two-micas granite is locally exposed in the northwestern part of the dome, showing pervasive C-S fabrics, which attests for its syn-kinematic emplacement. Muscovites from this granite give a plateau age of 78 Ma. Further south and east, the Uckapili granite represents a late-kinematic intrusion, showing only locally, at its roof, the development of C-S fabrics. For this granite, 40Ar/39Ar dating on muscovites and biotites gives plateau ages of 76 and 75 Ma, respectively. Altogether, the new 40Ar/39Ar data indicate that extensional exhumation of the Nigde dome was active during the Campanian, while field relations suggest that progressive unroofing beneath a northeast-dipping extensional detachment went on until Late Palaeocene times.
The E-W trending Reşadiye peninsula located at the southwestern part of the Anatolian Plate is an... more The E-W trending Reşadiye peninsula located at the southwestern part of the Anatolian Plate is an important horst developed between Gökova and Hisarönü Grabens. NW-trending the Datça Graben is the prominent structure comprising on the Reşadiye peninsula and records the significant fingerprints of palaeogeographical and kinematical characteristics from Pliocene to recent. The Datça Graben is controlled by NW-trending the Karaköy fault in the south and E-W trending the Kızlan fault in the north. Basement rocks of the graben are composed of ophiolitic rocks of the Lycian Nappes and Jurassic marine carbonates. The basinfill initiates with Early Pliocene Kızılaǧaç formation consisting conglomerates and continues with transgressive sequence (Yıldırımlı formation) composed of conglomerates, sandstones and marls with ignimbrite intercalations. Late Pliocene age was attributed to this formation based on the gastropoda and pelecypoda fauna according to previous studies. These units are unconf...
Hacettepe University Bulletin of Natural Sciences and Engineering Series B: Mathematics and Statistics
06800 Beytepe, ANKARA Geliş (received) : 18 Mayıs (May) 2011 Kabul (accepted) : 27 Haziran (June)... more 06800 Beytepe, ANKARA Geliş (received) : 18 Mayıs (May) 2011 Kabul (accepted) : 27 Haziran (June) 2011 ÖZ Miyosen Aksu Havzası, Afrika-Avrasya dalma batma zonunda, Anadolu yarımadasının güneyinde yer alan bir önül-ke (foreland) havzasıdır. Sığ denizel kırıntılılar ve karbonatlar ile karasal birimlerden oluşan havza çökel dolgusun-da, kaba taneli yelpaze deltası çökelleri önemli bir yere sahiptir. Bu çalışmada, Tortoniyen'de havzanın batı kena-rında depolanan, Kargı Yelpaze Deltası'nın yapısal ve sedimantolojik özellikleri incelenmiş, yelpaze deltasının geli-şimi tektonizma ve deniz seviyesi oynamaları bakımından değerlendirilmiştir. Farklı seviyelerinde yama resifleri bu-lunan kaba taneli yelpaze deltası istifi, fasiyes özellikleri, çökelme süreçleri ve çökelme alt ortamları (alüvyon yelpa-zesi, kıyı-lagün, delta önü) bakımından incelendiğinde, yelpaze deltasının hem regresif hem de transgresif gelişim gösterdiği görülmektedir. Ardalanmalı şekilde bulunan karasal ve sığ deni...
ABSTRACT The Aksu Basin, within the Isparta Angle, is located to the north of the intersection of... more ABSTRACT The Aksu Basin, within the Isparta Angle, is located to the north of the intersection of the Aegean and Cyprus arcs and has been evolving since the Middle Miocene. Correlation of: (1) kinematic analysis of fault planes that cut the basin fill, (2) the reactivation/inversion of fault planes and (3) sedimentological data indicate that the Aksu Basin has evolved by four alternating compressional and extensional tectonic phases since its formation. The first phase was NW-SE oriented compression caused by the emplacement of the Lycian Nappes which ended in Langhian. This compressional phase that induced the formation and the initial deformation of the basin was followed by a NW-SE extensional phase. This tectonic phase prevailed between the Langhian and Messinian and was terminated by a NE-SW compressional regime known as the Aksu Phase. The neotectonic period is characterized by NE-SW extension and began in the Late Pliocene. Correlation with the existing tectonic literature shows that the order of deformational phases proposed in this study might also be valid for the entire Isparta Angle area.
The timing of exhumation of high-grade metamorphic rocks and granitoids of the Nigde dome, in sou... more The timing of exhumation of high-grade metamorphic rocks and granitoids of the Nigde dome, in southern Central Anatolia, is a matter of debate. Our investigations show that the Nigde metamorphics must have reached the surface before the Eocene, as a sedimentary sequence of earliest Eocene to Middle Eocene age nonconformably overlies the high-grade rocks of the dome, and reworks them as pebbles. In contrast, Maastrichtian-Late Palaeocene sediments lie against the dome through a series of low-angle faults. These deposits are devoid of clasts originating from the high-grade rocks, suggesting that the Nigde metamorphics did not reach the surface before Late Palaeocene times. Structural analysis documents the existence of an extensional detachment at the top of the Nigde dome, superposing a superficial unit made up of massive ophiolitic rocks onto the high-grade metamorphics. Top-to-northeast pervasive shearing in the footwall becomes localized in a 100 m-thick zone of mylonites beneath ...
The present study highlights the hydrogeological and hydrogeochemical characteristics of the CO2-... more The present study highlights the hydrogeological and hydrogeochemical characteristics of the CO2-rich thermal–mineral waters in Kayseri, Turkey. These waters of Dokuzpınar cold spring (DPS) (12–13°C), Yeşilhisar mineral spring (YMS) (13–16°C), Acısu mineral spring (ACMS) (20–22.5°C), Tekgöz thermal spring (TGS) (40–41°C), and Bayramhacı thermal-mineral spring (BTMS) (45–46.5°C) have different physical and chemical compositions. The waters are located within the Erciyes basin in the Central Anatolian Crystalline complex consisting of three main rock units. Metamorphic/crystalline rocks occur as the basement, sedimentary rocks of Upper Cretaceous-Quaternary age form the cover, and volcanosedimentary rocks Miocene-Quaternary in age represent the extrusive products of magmatism acting in that period. All these units are covered unconformably by terrace and alluvial deposits, and travertine occurrences have variable permeability. Dokuzpinar cold spring, YMS and ACMS localized mainly along the faults within the region have higher Na+ and Cl− contents whereas TGS and BTMS have higher amounts of Ca2+ and HCO 3−. The high concentrations of Ca2+ and HCO 3− are mainly related to the high CO2 contents resulting from interactions with carbonate rocks. Whereas the high Na+ content is derived from the alkaline rocks, such as syenite, tuff and basalts, the Cl− is generally connected to the dissolution of the evaporitic sequences. These waters are of meteoric-type. BTMS deviates from meteoric water line. The content is related to the increases in the δ18O compositions due to mineral–water interaction (re-equilibrium) process. CO2-dominated YMS and ACMS with low temperatures have higher mineralizations. Yeşilhisar mineral spring, ACMS, TGS and BTMS are oversaturated in terms of calcite, aragonite, dolomite, goethite and hematite, and undersaturated with respect to gypsum, halite and anhydrite. Yeşilhisar mineral spring, ACMS and BTMS are also characterized by recent travertine precipitation. Dokuzpınar cold spring is undersaturated in terms of the above minerals. The higher ratios of Ca/Mg and Cl/HCO3, and lower ratios of SO4/Cl in BTMS than TGS suggest that TGS has shallow circulation compared to BTMS, and/or has much more heat-loss enroute the surface. The sequence of hydrogeochemical and isotopic compositions of the waters is in an order of DPS>YMS>ACMS>TGS>BTMS and this suggests a transition period from a shallow circulation to a deep circulation path.
Human activities and agriculture have had direct and indirect effects on the rates of contaminati... more Human activities and agriculture have had direct and indirect effects on the rates of contamination of groundwater in the Incesu-Dokuzpınar spring area. Direct effects include dissolution and transport of excess quantities of fertilizers with associated materials and hydrological alterations related to irrigation and drainage. Indirect effects may include changes in water–rock reactions in soils and aquifers caused by increased concentrations of dissolved oxidants, protons, and major ions. Agricultural activities have directly or indirectly affected the concentrations of a large number of inorganic chemicals in groundwater, for example NO3, N2, Cl, SO42, H+, K, Mg, Ca, Fe, Cu, B, Pb, and Zn, as well as a wide variety of pesticides and other organic compounds. For reactive contaminants like NO3, it is recommended that a combination of hydrochemical and environmental-tracer analytical approaches might be required to resolve changing inputs from subsequent alterations as causes of concentration gradients in groundwater. The water type of Dokuzpınar springs is mainly Na–Mg–Ca–Cl–HCO3. Note that the water types of the springs were directly related to the hydrogeochemical properties of outcrops at the study area. Thus, the high concentration of Ca2+ and HCO3 is mainly related to the high CO2 contents in the marbles, whereas the high Na concentration arises from the existing syenite, volcanic ash, basalt, and clay units, although the İncesu-Dokuzpınar springs cover most of the drinking and irrigation water demands of this area. The high concentrations of NO3 and NaCl show that the area around the springs is continuously being contaminated by untreated sewage and agricultural wastes, especially during dry periods. Therefore, this approach is based on the vulnerability studies of the catchment area, determination of the transfer time of the pollutant, and the water-bearing formations of İncesu-Dokuzpınar springs. Vulnerability in this study is defined as the intrinsic hydrogeochemical characteristics of an aquifer, which may show the sensitivity of groundwater to be contaminated by different human activities.
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