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• MakaleYalnız künye2026/r/gumushane/13852
  Crustal 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.

  İncele
• Kitap BölümüYalnız künye2026/r/gumushane/13474
  The 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.

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• MakaleAçık Erişim2025/r/gumushane/14010
  MOHO DEPTH IN THE SOUTH CASPIAN BASIN ESTIMATED FROM GRAVITY FIELD DATA AND LOCATION OF HYDROCARBON RESERVOIRS

  Kadirov, F.A.; Safarov, R.T.; Gahramanov, M.R.; Maden, N.M.

  The South Caspian Basin (SCB) is a geologically complex and diverse region of significant scientific interest due to its hydrocarbon resources and intricate crustal structure. This study provides an updated interpretation of the SCB’s crustal configuration using gravity-derived data, with particular emphasis on delineating Moho depth and the influence of its variations on petroleum basins. The crustal structure of the basin is assessed using Bouguer gravity anomalies, incorporating terrestrial and marine gravity measurements, and processed with spectral analysis methods. Power spectrum analysis was applied to estimate the depths of subsurface mass distributions affecting the gravity field, enabling separation of regional and residual anomalies and providing an initial reference depth of Moho. These results served as input for Parker–Oldenburg inversion, an iterative Fourier-based technique used to model the Moho surface by minimizing discrepancies between observed and calculated gravity anomalies. The integrated approach reveals substantial lateral variations in Moho depth, ranging from approximately 42 km in the Absheron–Prebalkhan zone to about 29 km in the central SCB. Analysis of spatial correlations indicates that oil and gas reservoirs are primarily located in areas where the Moho surface is deeper and along gradient zones marking abrupt depth changes. These findings enhance understanding of the complex tectonic evolution of the SCB and provide valuable constraints for predicting potential hydrocarbon locations in this tectonically active and data-scarce region.

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• MakaleYalnız künye2025/r/gumushane/12548
  Mantle genesis and crustal contamination in Carboniferous granitoids using U-Th-K concentrations at the Akşar Pluton in the Eastern Pontides, NE Türkiye

  Maden, Nafız; Gücer, Mehmet Ali; Akaryalı, Enver

  New radiogenic heat production (RHP) data are presented for Carboniferous granites outcropping in the Akşar region (Bayburt, NE Turkey) to contribute to ongoing debates on the genetic and lithologic relationship between the Akşar and Gümüşhane plutons, which is the most widely distributed granitic rocks in the region. The scope of this study consists of rocks composed of enriched mantle material metasomatized by fluids from the previously subducted plate. We observed average K value for the Akşar Pluton was found to be 3.09 ± 1.58 %. Additionally, average Th/U and U/Th values of 3.95 ± 1.37 and 0.29 ± 0.10, respectively. The calculated RHP value for the Akşar Pluton was 2.20 ± 0.56 μWm−3. Numerical results suggest that the Carboniferous Akşar pluton's primary magma was the product of mixing lithospheric mantle and mid-to-lower crustal melts because of partial melting, differentiation, and emplacement in the shallow continental magma chamber. The geochemical and petrogenetic characteristics of the Akşar region magmas suggest that crustal contamination occurred at multiple levels, particularly within the lower to middle crust of the plutonic core complex. This complex likely retains geochemical signatures indicative of subducted Paleotethys oceanic lithosphere. These findings provide critical insights into the magmatic evolution of the Eastern Pontides, contributing to a more comprehensive understanding of crust–mantle interactions and the broader geodynamic framework of northeastern Türkiye.

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• MakaleAçık Erişim2024/r/gumushane/20068
  Gümüşhane 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.

  İncele
• MakaleYalnız künye2024/r/gumushane/12709
  Hydrocarbon 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.

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• MakaleYalnız künye2023/r/gumushane/14453
  Local 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.

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• MakaleYalnız künye2023/r/gumushane/12743
  Hydrocarbon 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.

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• MakaleYalnız künye2022/r/gumushane/12690
  Secular 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.

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• MakaleYalnız künye2022/r/gumushane/11807
  Major 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.

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