Sürdürülebilir Kalkınma Amaçları
Yayınlar
- MakaleYalnız künye2026Crustal structure and major tectonic features of the South Caspian Basin: Insight from Bouguer gravity data
Kadirov, Fakhraddin; Maden, Nafiz; Safarov, Rafig; Gahramanov, Murad
The South Caspian Basin is characterized by high tectonic activity, which resulted in the presence of significant hydrocarbon resources that are currently being exploited. This has led to a surge in research efforts, as the basin's substantial hydrocarbon reserves, coupled with its complex tectonic history, attract considerable scientific interest. This research study aims to contribute to our understanding of the crustal structure of the South Caspian Basin. To achieve this objective, we employed geophysical techniques, with a primary focus on analyzing Bouguer gravity data, power spectrum analysis, and edge detection methods. This comprehensive approach, integrating diverse methodologies, provided substantial advancements in our understanding of the basin's geological framework, with valuable insights into the tectonic processes operating in the region. In the Absheron-Prebalkhan zone, the Moho depth was constrained to an estimated 42 km. The investigation further reveals a constriction of the area towards the east, reaching a depth of 36 km near Prebalkhan and a final depth of 39 km within Prebalkhan itself. The total horizontal gradient technique and the logistic filter were implemented on the gravity data of the study region to figure out faults, geological boundaries, and structural lineaments within the South Caspian Basin.
- Kitap BölümüYalnız künye2026The Influence of the Anglo-American Alliance on Shaping Iranian Foreign Policy
Topal, Coşkun; Bülbül, Berke; Maden, Nafiz
Since the 19thcentury, Britishoilinterests and geopoliticalbalancing against Russia positionedIran as a criticalbuffer zone. The Anglo-American-backed1953Operation Ajax generateda traumatic collective memory that formedthe ideological foundation of Iranian foreign policy after the 1979 Revolution. In the post-revolutionary era, Tehran transitioned into a security-oriented state, adopting severe anti-imperialist rhetoric against US and UK. Confronting US economic sanctions, “rogue state” labeling, andnuclearcounter-pressures, Iranbuiltasymmetricresistancemechanisms through the “Shia Crescent” and regional proxy networks. Meanwhile, diplomatic crises with UK, such as the Salman Rushdie affair, further hardened this defensive stance. This study examines how Iran transforms Anglo-American threat perceptions into a source of regime legitimacy and strategic autonomy.
- MakaleAçık Erişim2024Gümüşhane ilinde deprem ivme ve manyetik alan istasyonlarının kurulumu ve işletilmesi
Öztürk, Serkan; Maden, Nafiz; Beker, Yasemin; Sari, Mahmut; Pehlivan, Levent
Bu çalışmada, Kuzey Anadolu Fay Zonu (KAFZ) üzerinde meydana gelen bir depremden Gümüşhane ilinin etkilenme derecesini belirlemek üzere deprem ivme kayıt cihazlarının yerleştirilmesi ve Güneşte meydana gelen fırtınalar nedeniyle yer Manyetik alanındaki değişimleri gözlemlemek amacıyla 3 bileşen Flux-Gate manyetometrenin kurulumu amaçlanmıştır. Deprem ivme kayıt cihazlarının (3 adet); Gümüşhane ili için önem taşıyan Karaca Mağarası ve Kürtün hidroelektrik santrali ile KAFZ’na yakınlığından dolayı Şiran MYO’na kurulması uygun görülmüştür. Flux-gate Manyetometresi ise Gümüşhane Merkez ilçede kurulmuştur. KAFZ üzerinde meydana gelen bir depremden Kelkit, Şiran ve Köse ilçeleri daha çok etkilenirken Torul ve Kürtün ilçeleri daha az etkilenmektedir. Gümüşhane’nin 17 km kuzeybatısında yer alan Karaca Mağarası bölgemizin önemli turizm merkezlerinden birisidir. Kürtün ilçesinde, Harşit nehri üzerinde kurulu olan Kürtün Hidroelektrik santrali enerji amaçlı olarak hizmet vermesi yanında baraj gölü üzerinde balık üretimine ve su sporları yapılmasına imkân sunmaktadır. Güneşte aniden gelişen çok şiddetli patlamalar dünyaya ulaştıklarında elektrik ve iletişim hatlarını kesilebilmekte, radyo haberleşmesinde bozulmalara ve radyasyona sebep olmaktadır. Gümüşhane kurşun, çinko, bakır, altın ve gümüş gibi değerli metaller açısından oldukça yüksek bir potansiyele sahiptir. Bu tür maden yataklarının belirlenmesinde Jeofizik yöntemlerden bir tanesi olan Manyetik yöntem oldukça başarılı bir şekilde kullanılmaktadır. Bu yöntemde arazide ölçü alınırken yer manyetik alanının sürekli kaydedilmesine hizmet edecektir.
- MakaleYalnız künye2024Hydrocarbon migration and structural reservoir traps in the Western Black Sea Basin: evidence from satellite-derived gravity tensor data
Maden, Nafiz; Doğru, Fikret
The Black Sea, situated between Türkiye, Bulgaria, Romania, Ukraine, and Russia, is tectonically separated into two different sub-basins: Eastern and Western Black Sea. These two sub-basins have been a target of interest for oil and gas exploration for several decades. Although the participation of the Black Sea Basin in the global oil market is very small compared to the Caspian Sea, this basin is considered a potential hydrocarbon deposit since both areas have similar characteristics in terms of source rock. In this study, satellite-derived Bouguer and free-air gravity data were interpreted to disclose the prospective hydrocarbon reservoirs and gas hydrate deposits within the Western Black Sea Basin. The locations of the maxima identified in the I2 invariants map were assessed as five substantial hydrocarbon prospective zones three of which are in the Turkish Exclusive Economic Zone. Numerous oil and gas seeps are evidence of lateral and vertical hydrocarbon migration from the source rock through major faults in the WBSB where the maximum I2 anomalies are observed.
- MakaleYalnız künye2023Local gravity and magnetic anomalies associated with the oil and gas reservoirs in the cretaceous carbonate deposits of Yevlakh-Agjabedi depression, Azerbaijan
Gadirov, Vagif G.; Maden, Nafiz; Gadirov, Kamran V.
Local gravity and magnetic anomalies are employed to identify potential hydrocarbon reservoirs in the Middle Kura Depression (MKD) within the South Caspian basin in Azerbaijan. The MKD basin in Azerbaijan including the Yevlakh-Agjabedi trough covers a large part of the Kura intermountain basin between the Greater and Lesser Caucasus. In the study region, several local gravity and magnetic anomalies are discovered related to oil and gas deposits in the sedimentary depression whose thickness is 12–14 km. Gravity minima and maxima expressed by different wavelength anomalies are indicative of density variations within the basin. Local gravity minima with an intensity of 0.3–0.4 mGal identified in the study areas are related to the oil–gas deposits. While the local positive magnetic anomalies are associated with the volcanic formations, local negative magnetic anomalies appear over the productive parts of the buried structure within the sedimentary complex. Intense local magnetic minima anomalies with an intensity of 20–30 nT are evidence of oil and gas accumulations. The limitations of traditional methods for interpreting gravity and magnetic data to locate oil and gas fields have led to the use of gravity field gradients. This alternative approach has proven advantageous, as it confirms the results of gravity exploration and is useful for directly searching for hydrocarbons.
- MakaleYalnız künye2023Hydrocarbon reservoir depth identification in the eastern black sea basin: Implications from euler deconvolution and gravity tensor invariants
Doğru, Fikret; Maden, Nafiz
The Black Sea Basin (BSB) consisting of Eastern Black Sea (EBS) and Western Black Sea (WBS) basins which separated by the Mid Black Sea High (MBSH) is formed by the collision of Eurasia and Arabian-African Plates. Petroleum and gas hydrate contents of the BSB have been discussed by using different geological and geophysical research. In this study, the gravity gradient tensor and invariant data based on the Bouguer gravity anomaly of the EBS basin were evaluated to define the hydrocarbon reservoirs. Afterwards, Euler deconvolution technique is applied to the invariant to reveal the depth of subsurface bodies. Furthermore, the significant invariant anomalies are compared with known oil seepage and petroleum wells. The depth values of oil trace closest to the known Sürmene and Hopa drill holes were computed as 4809 m, and 4455 m according to the structural index values of SI = 2.
- MakaleYalnız künye2022Secular variation of magnetic declination for the past 500 years from Empire to Republic in Anatolia
Maden, Nafiz; Yıldız, Burak
Seydi Ali Reis first mentioned the declination angle in his book titled Kitab-ı Muhit in 1554. Kitab-ı Cihannüma (1654), Füyuzat-i Mıknatisiye (1731), and Mârifetname (1757) gave the magnetic declination angle values in Anatolia. We have compiled magnetic declination data from 1500 to the present day in Anatolia and Istanbul. The plot of the magnetic declination angle was drawn for the first time using historical data between 1500 and 1947 for Istanbul. Three new magnetic declination maps for the periods of 1909–1910, 1970 and 2009 were produced for Turkey. The annual change map based on the data of 1970 and 2009 is also given for whole Turkey. The agonic line extending in NW-SE direction between Sinop and Antep divides Anatolia into two regions in 1910. The mean declination values obtained from qibla direction measurements made by the Presidency of Religious Affairs in all mosques give 3.11° E for 1970 and 4.74° E for 2009 in Turkey.
- MakaleYalnız künye2022Major tectonic features and geodynamic setting of the Black Sea Basin: Evidence from satellite-derived gravity, heat flow, and seismological data
Maden, Nafiz; Elmas, Ali
The origin and development of the Black Sea Basin (BSB) remain controversial. In this study, we determined the main tectonic features of the BSB using satellite gravity, heat flow, and seismological data. Positive gravity anomalies are observed in the arc region due to high-density material, while negative gravity anomalies are seen in the trench region owing to the mass deficiency and sediments. The trench region has a relatively low heat flow anomalies along the Black Sea coasts. The Moho depth increases from 18.11 km in the Eastern Black Sea Basin (EBSB) to 51.83 km in the Eastern Anatolia Plateau (EAP) with an average of 34.13 ± 6.15 km. The lithosphere thickness changed between 78.48 km beneath Anatolia and 120.57 km below the EBSB with an average of 99.17 ± 8.17 km. The low heat flow and Moho temperature values indicate that the lithosphere is strong and cold beneath the BSB. The numerical results, therefore, provide evidence for southward subduction of the Tethys oceanic lithosphere below the Anatolian plate during the late Mesozoic-Cenozoic. Considering all geophysical and geological data, we conclude that the Black Sea Basin represents a relict basin, rather than a back-arc basin.
- DüzeltmeAçık Erişim2021Correction to: Crustal Contamination of Tertiary Volcanic Rocks: Evidence from K, U, Th and Radiogenic Heat Production Data in Eastern Pontides (NE Turkey) (Pure and Applied Geophysics, (2021), 178, 5, (1871-1888), 10.1007/s00024-021-02739-6)
Maden, Nafiz; Akaryalı, Enver; Aydınçakır, Emre
In the original version of this paper the captions of figures 5, 6 and 7 were inadvertently interchanged.
- MakaleYalnız künye2021Crustal Contamination of Tertiary Volcanic Rocks: Evidence from K, U, Th and Radiogenic Heat Production Data in Eastern Pontides (NE Turkey)
Maden, Nafiz; Akaryalı, Enver; Aydınçakır, Emre
Herein, we present new 238U, 232Th, and 40K radionuclide concentrations, density and radiogenic heat production (RHP) data on the Tertiary volcanic rocks outcropping in Borçka, Gumushane and Trabzon regions within the Eastern Pontide Orogenic Belt (EPOB). The mean K values for Trabzon, Borçka and Gümüşhane regions were 2.19 ± 0.87%, 0.90 ± 0.70% and 0.59 ± 0.25%, respectively, the mean U values for Trabzon, Borçka and Gümüşhane regions were 2.12 ± 0.76 ppm and 1.29 ± 0.68 ppm and 0.90 ± 0.32 ppm, and the average Th values were calculated as 6.54 ± 2.32 ppm, 2.49 ± 1.93 ppm and 1.33 ± 0.60 ppm for Trabzon, Borçka and Gümüşhane regions, respectively. The average Th/U values are 3.38 ± 1.48 for the Trabzon region, 2.01 ± 1.22 for the Borçka region, and 1.69 ± 1.09 for the Gümüşhane region. Average U/Th values were calculated as 0.35 ± 0.14, 0.71 ± 0.52 and 0.89 ± 0.72 for the Trabzon, Borçka and Gümüşhane regions, respectively. The RHP values were determined as 1.16 ± 0.35 μW m - 3, 0.58 ± 0.33 μW m - 3 and 0.37 ± 0.10 μW m - 3 for Trabzon, Borçka and Gümüşhane regions, respectively. The Tertiary aged rocks in the EPOB that we have examined within this study scope have been derived from an enriched mantle, previously metasomatized by fluids derived from subducted slab. The parental magma of Eocene basaltic rocks was contaminated with crustal material during the ascension of the magma through the crust or in the shallow-level crustal magma chambers.
- Kitap BölümüYalnız künye2020Geothermal Potential and Circulation Depth of Hudai Thermal Springs (Sandikli-Afyonkarahisar, Turkiye) Using Magnetic, Geothermometry and Heat Flow Data
Maden, Nafiz; Afsin, Mustafa; Aksever, Fatma; Davraz, Aysen; Biswas, A; Sharma, SP
The Hudai-Sandikli geothermal basin having 23 thermal productivity wells is a significant geothermal energy source field. The analysis of power spectrum, conventional heat flow and silica heat flow methods were implemented to identify the geothermal waters circulation depth, depth to Curie point and surface heat flow rate in the Hudai-Sandikli geothermal field. Hydrogeochemical facies of geothermal immature ancient waters having deep circulation in lower hydraulic conductive aquifers are Na-Ca-HCO3-SO4 and Na-Ca-SO4-HCO3, which is represented very high ion content because of extensive contact with rocks. The heat conduction law is employed to specify the rate of heat flow using the geothermal gradient value. The numerical results determined from silica geothermometer method, the mean heat flow density and Curie temperature depth are obtained as 103.69 mWm(-2) and 11.81 km, respectively. The study region was represented by a mean geothermal gradient of 49.18 degrees C km(-1) yielding average reservoir depths of 0.90 km. The estimated Curie temperature, heat flow, reservoir temperature values demonstrated that the region indicates significant geothermal energy potential because of the partial melting of lithospheric crust.
- MakaleAçık Erişim2020Historical aurora borealis catalog for Anatolia and Constantinople (hABcAC) during the Eastern Roman Empire period: Implications for past solar activity
Maden, Nafiz
Herein, Anatolian aurorae are reviewed based on the existing catalogs to establish a relationship between the aurora observations and past solar activity during the Medieval period. For this purpose, historical aurora catalogs for Constantinople and Anatolia are compiled based on the existing catalogs and compared with those in the Middle East region. The available catalogs in the literature are mostly related to the records observed in Europe, Japan, China, Russia, and the Middle East. There is no study dealing only with the historical aurora observations recorded in Anatolia and Constantinople. The data of the catalog show that there is a considerable relationship between the aurora activity and past strong solar activity. High auroral activity around the extreme solar particle storm in 774/775 and the Medieval grand maximum in the 1100s in Anatolia and the Middle East is quite consistent with the past solar variability reported in other scientific literature.
- MakaleAçık Erişim2020Excess lifetime cancer risk due to natural radioactivity in Gümüşhane Province, NE Turkey
Maden, Nafiz; Akaryali, Enver; Gücer, Mehmet Ali
In this study, 162 in situ measurements of 238U, 232Th, and 40K radionuclide concentrations dataset taken by the gamma-ray spectrometer in Gümüşhane, Turkey are presented. The gamma ray measurements were performed by a 512-channel, three-window gamma-ray spectrometry equipment made by GF Instruments. We first observed the radionuclides of the 238U,232Th, and 40K values in Gümüşhane. We then calculated the hazard indices of gamma radiation such as annual effective dose equivalent (AEDE), internal and external hazard index (Hin, Hex), and excess lifetime cancer risk (ELCR) based on the radionuclide abundances of 238U, 232Th, and 40K for the first time. In Gümüşhane, the average activity concentrations of radionuclides 238U, 232Th, and 40K were measured as 58.7 ± 34.3 Bq kg-1, 62.7 ± 37.2 Bq kg-1, and 1026.8 ± 486.0 Bq kg-1, respectively. The average outdoor annual effective dose equivalent and ELCR values were 132.2 ± 63.2 mSv yr-1 and 0.40 ± 0.19 × 10-3, respectively. Numerical results indicate that the radiological parameters (AEDE and ELCR) obtained for Gümüşhane Province were greater than the world’s mean values.
- MakaleYalnız künye2019The in situ natural radionuclide (238U,232Th and40K) concentrations in Gümüşhane granitoids: implications for radiological hazard levels of Gümüşhane city, northeast Turkey
Maden, Nafiz; Akaryalı, Enver; Çelik, Necati
We have carried out 48 in situ measurements on radioactivities of 238U, 232Th and 40K isotopes at the Gümüşhane granitoid plutons employing gamma-ray spectrometer with a NaI(Tl) scintillation detector. The radionuclide activity concentrations of 40K, 238U and 232Th ranged from 62.6 to 1680.8 Bq kg−1, 2.5 to 119.9 Bq kg−1 and 3.3 to 92.4 Bq kg−1, respectively. The mean concentration of natural radionuclides (40K, 238U and 232Th) was found to be 638.5 ± 421.6 Bq kg−1, 40.8 ± 27.4 Bq kg−1 and 33.5 ± 25.5 Bq kg−1, respectively. The mean values of the radium equivalent and the external hazard index were 137.9 ± 80.6 Bq kg−1 and 0.37 ± 0.22, respectively. The value of annual effective dose equivalent value (81.8 μSv year−1) is lower on average than in the world average of 460 μSv year−1. The external hazard index acquired in this study did not exceed the international safety standard levels, which means that Gümüşhane pluton does not produce any radiation hazards to the dwellers.
- MakaleAçık Erişim2018Natural Events and Earth Sciences Observations in the Chronicle of Theophanes
Maden, Nafiz; Beker, Yasemin; Nazir, Bayram
The purpose of this work is the natural phenomena and earth sciences observations recorded in the chronicle of the Byzantine historian Theophanes from AD 284 to 813. Theophanes was born in 758/760 in Istanbul as a child of a wealthy and aristocratic family and died in exile of Samothroke island in 818. His mother name is Theodora and his father is Isaakios, the governor of the Mediterranean islands of the Byzantine Empire. Theophanes decided to continue unfinished chronic of Georgios Synkellos who died in the year 810/811 with the encouragement and desire of him. He completed his work entitled “Chronographia” covering the period between 284 and 813 years in 810-814. The chronicle of Theophanes including 90 natural events and earth sciences records is very important in terms of using very old and lost resources.
- Proje2018Doğu Pontid Orojenik kuşağında yerleşen volkanik kayaçların Radyojenik ısı üretim (RHP) potansiyelinin belirlenmesi
Aydınçakır, Emre; Akaryali, Enver; Maden, Nafiz
Bu çalısmada Dogu Pontid Orojenik kusagında (KD TÜRKIYE) yer alan Artvin-Borçka, Gümüshane ve Trabzon civarında yüzeyleyen Tersiyer yaslı volkanik kayaçların radyojenik ısı üretimi ve bunun jeolojik kaynakları ortaya konulması hedeflenmistir. Böylece yüzeydeki radyojenik ısı üretimi (RHP) ile kabugun derinliklerindeki ısı akısı arasında iliskinin kurulması saglanmıstır. Yüzeyde ölçülen ısı akısı üst kabuk içindeki radyoaktif elementlerin parçalanması sonucunda ortaya çıkan ısı (radyojenik ısı) ile alt kabuk-üst mantodan aktarılan ısı olmak üzere iki farklı kaynaktan olusmaktadır. RHP üst kabukta yer alan kayaçların bünyesinde bulunan Uranyum (U, ppm), Toryum (Th, ppm) ve Potasyum (K, %) gibi radyoaktif elementlerin bozunması sonucu olusmakta ve yüzeydeki ısı akısına katılmaktadır. Bu projede çalısmasında RHP degerlerini belirlemek için kayaçların bünyelerinde yer alan U, Th ve K degerleri Gamma Ray Spektrometre cihazı ile ölçülmüstür. Ortalama K degerleri Trabzon, Borçka ve Gümüshane yöreleri için sırasıyla 2,19±0,87%, 0.90±0.70% ve 0.59±0.53%, ortalama U degerleri Trabzon, Borçka ve Gümüshane yöreleri için sırasıyla 2,11±0,77ppm, 1.29±0.68ppm ve 0.90±0.32ppm, ortalama Th degerleri ise Trabzon, Borçka ve Gümüshane yöreleri için sırasıyla 6,55±2,32ppm, 2.49±1.93ppm ve 1.33±0.60ppm olarak hesaplanmıstır. Ortalama Th/U degerleri Trabzon için 4.21±1.0; Borçka yöresi için 2.81±0.8 ve Gümüshane yöresi için 4.01±1.0 olarak; ortalama U/Th degerleri Trabzon yöresinde 0.25±0.1, Borçka yöresinde 0.39±0.1 ve Gümüshane yöresinde 0.27±0.1 olarak hesap edilmistir. Proje kapsamında toplanan toplam 100 adet kayacın ortalama yogunluk degerleri Trabzon, Borçka ve Gümüshane yöreleri için sırasıyla 2.61±0.23 grcm-3, 2.64±0.18 grcm-3 ve 2.62±0.13 grcm-3 olarak tespit edilmistir. K, U, Th ve yogunluk verileriyle RHP degerleri üç farklı bölge için hesaplandıgında Trabzon için 1,16±0,35 ?Wm^(-3), Borçka için 0.58±0.33 ?Wm^(-3) ve Gümüshane için 0.37±0.11 ?Wm^(-3)olarak belirlenmistir. Bu proje kapsamında inceledigimiz Dogu Pontid orojenik kusagında yer alan Tersiyer yaslı kayaçların tüm bölgelere ait veriler degerlendirilerek üst manto kaynaklı magmadan yitim iliskili olarak türedikleri sonucuna ulasılmıstır. Magmanın yükselmesi asamasında yada magma odacıklarında alt kıtasal kabuk malzemelerince kirletildigi kanaatine varılmıstır.
- MakaleYalnız künye2017Kaletaş (Gümüşhane) Au Madeninde Cevher Yerleşimine Bağlı Gelişen Alterasyon Zonlarının Gamma Işın Spekrometresi ile Belirlenmesi: Örnek Bir Çalışma
Maden, Nafiz; Yiğit, Yılmaz
Bu çalışmada Kaletaş (Gümüşhane, KD Türkiye) yöresinde toplam 198 noktada Potasyum (K), Uranyum (eU), Toryum (eTh) konsantrasyonu ve Doğal Doz Oranı değerleri Gamma Ray Spektrometre cihazı ile ölçülmüştür. Potasyum (K), Uranyum (eU), Toryum (eTh) ve Doğal Doz Oranı haritaları değerlendirildiğinde yüksek genlikli anomalilerin bozunmaya bağlı K zenginleşmesi gösteren kırık hatları boyunca yerleştiği görülmüştür. Yüksek genlikli K/eTh, K/eU ve efimov F-parametre (KeU/eTh) anomalileri hidrotermal çözeltilere bağlı bozunma zonlarına işaret etmektedir. Hızlı ve ekonomik bir yöntem olan gamma ray spektrometre yöntemi K bozunmasına bağlı cevher zonlarının belirlenmesinde kullanılabilir. Ayrıca, yüksek genlikli efimov F-parametre anomalileri potansiyel cevher sahalarını göstermekte olup sondaj noktaları olarak kullanılması mümkündür.
- MakaleYalnız künye2016Investigation of the Ünlüpınar, Eylence Yayla (Kelkit-Gümüşhane) Epithermal Pb-Zn±Au Mineralization with Gamma Ray Spectrometer Measurements
Maden, Nafiz; Kahveci, Nezaket
In this study, the values of Potassium (K40), Uranium (eU), Thorium (eTh) and total dose rates in 320 stations were acquired through a high-sensitivity gamma-ray spectrometer. The maps of the Potassium (K40), Uranium (eU), Thorium (eTh) and total dose rates with theirs computed ratio maps are plotted. It is seen that the high magnitude of the anomalies are located through the fault lines related to the enrichment of K by evaluating these ratio maps. High K/eTh, K/eU and Efimov F-Parameter (KeU/eTh) anomalies point out the alteration zones with transmitting hydrothermal ore solutions. It is seen that the ore zones associated with the alteration could be determined with the gamma ray spectrometry, which is fast and economics method. Also, the high amplitude areas in the Efimov F-Parameter map demonstrate the potential ore zones and might be the mine drilling points.
- MakaleYalnız künye2015A review for genesis of continental arc magmas: U, Th, K and radiogenic heat production data from the Gümüşhane Pluton in the Eastern Pontides (NE Türkiye)
Maden, Nafiz; Akaryali, Enver
In this study, in situ radioelemental (238U, 232Th and 40K) measurements and heat production rate evaluation have been conducted at 132 sites in the Gümüşhane Pluton of the Eastern Pontides Orogenic Belt (EPOG) of Northern Türkiye. The average K, U and Th values for granites are 4.35±0.71%, 5.85±2.74ppm, 22.13±5.55ppm, respectively; microgranites 4.33±1.37%, 7.12±2.23ppm, 24.11±9.59ppm; metagranite 3.93±0.68%, 6.24±2.75ppm, 12.87±3.92ppm; andesite/basalt 1.75±0.74%, 3.22±1.07ppm, 9.01±5.14ppm. Based on the abundances of K, U and Th, the radiogenic heat production (RHP) values, which is a reflection of the geological rock types, are estimated as 3.52±1.03μWm-3, 3.86±1.31μWm-3, 2.93±0.89μWm-3, and 1.68±0.63μWm-3 for granites, microgranites, metagranites and andesite/basalt, respectively. The average heat production value for the study area is estimated as 2.83±1.39μWm-3, which is closer to the upper continental crustal value; contrary to the highest heat production value of granitic basement and the lowest heat production values of the sedimentary rocks. The study region is depicted with very high level of Th/U value ranging from 0.11 to 23.19 with mean value of 3.53 ± 2.5, which is comparatively close to the upper continental crustal estimate of 3.8. The numerical results verify that mantle-derived magmas are subjected to contamination with both middle and lower crustal material constituted by fragments of southerly dipping subduction of Tethys Ocean during the late Mesozoic-Cenozoic.
- MakaleYalnız künye2015Determination of the Crustal and Thermal Structure of the Erzurum-Horasan-Pasinler Basins (Eastern Türkiye) Using Gravity and Magnetic Data
Maden, Nafiz; Aydin, Ali; Kadirov, Fakhraddin
The Erzurum-Horasan-Pasinler basin, which surrounds Miocene rocks, is oriented approximately E–W and is located in Eastern Anatolia (Türkiye). East Anatolia, where ophiolitic and young volcanic rocks are widespread, is situated in the Alpine–Himalayan fold-thrust fault belt. The NW–SE trending North Anatolian Transform Fault Zone and the NE–SW trending East Anatolian Transform Fault Zone, formed by the compressional regime of East Anatolia, control the main tectonics of the study region. While the Moho and Conrad depths of the study region are 43.0 and 20.9 km, respectively, the average sedimentary thickness has been determined to be 5.2 km by using the power spectrum method. On the other hand, it is found that the depth of the Moho in the region varies from 41.0 to 44.5 km and the depth of the Conrad discontinuity varies between 22 and 26 km, as computed using empirical equations. The basement of the sedimentary layer is calculated to be 6 km by using inversion results applied to the residual gravity data. The Curie point depth and average heat flow value in this region are calculated as 18.0 km and 89.1 m Wm−2, respectively. Geotherm calculations reveal that the Moho temperature is 1,028.0 °C based on the crustal model. The high heat flow values obtained are attributed to tectonic activities and melting of the lithospheric mantle caused by upwelling of the asthenosphere.