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Sürdürülebilir Kalkınma Amaçları

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• MakaleYalnız künye2026/r/gumushane/10637
  Geochemical signature, detrital zircon U-Pb, and mica Ar-Ar age systematics from the Karadere Basement Unit of the İstanbul-Zonguldak Terrane (NW, Türkiye): evidence for an Avalonian-Cadomian active continental margin

  Çimen, Okay; Gücer, Mehmet Ali; Göncüoglu, Mehmet Cemal; Akal, Cuneyt; Arslan, Mehmet; Simonetti, Antonio; Karaoglan, Fatih

  The & Idot;stanbul-Zonguldak Terrane is located in northwest Anatolia and includes several outcrops with pre-Cambrian basement units. The Karadere Basement Unit represents the easternmost basement of this terrane and is composed of paragneiss, quartzite, and orthogneiss. The paragneiss and quartzite are cut by orthogneisses and disconformably overlain by Lower Ordovician to Middle Devonian cover units. Its pre-Cambrian to Palaeozoic tectonic evolution remains poorly understood, and therefore, this study reports whole-rock trace element signatures, detrital zircon U-Pb, and muscovite Ar-Ar age data for samples of paragneiss, quartzite, amphibolite, and orthogneiss. The whole-rock geochemical data indicate that the protoliths of the paragneiss and quartzite samples investigated here could have been derived from arc-related felsic magmatic units located in an active continental margin. The protoliths of amphibolites and orthogneiss samples are gabbro and granite, respectively, and their geochemical signatures are akin to those from continental arc igneous suites. The detrital zircon U-Pb data are characterized by predominantly Mesoproterozoic (84%) and lesser amount of Palaeoproterozoic and Neoproterozoic ages and suggest an early Tonian (youngest peak age of 915 +/- 18 Ma) maximum depositional age. Moreover, zircon U-Pb dating analyses from an orthogneiss sample yielded an age of 603 +/- 2 Ma, indicating the occurrence of mid-Ediacaran arc magmatism. This represents one of the oldest Ediacaran ages obtained from the metamagmatic basement rocks of the & Idot;stanbul-Zonguldak Terrane. Ar-Ar dating of muscovite from ortho- and paragneiss samples yielded ages of 533 +/- 25 Ma and 530 +/- 9 Ma, respectively, which are interpreted as early Cambrian cooling ages. Overall, the combined results reported here reveal that the Karadere Basement Unit is markedly different from NE African basement units but displays similarities to the basement rocks of both Avalonian and Amazonian terranes. It may have been formed and metamorphosed in an Avalonian-Cadomian active continental margin during the mid- to late Neoproterozoic and early Cambrian.

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• MakaleYalnız künye2026/r/gumushane/13788
  Natural Radioactivity and Radiological Risk Assessment of Rocks Around the Mines: A Case Study From the Mastra and Hazine Mağara Mining Areas, Northeastern Türkiye

  Sipahi, Ferkan; Çelik, Necati; Gücer, Mehmet Ali; Dizman, Serdar

  This study presents a comprehensive assessment of natural radioactivity levels and associated radiological hazards in rock samples collected from Mastra and Hazine Mağara mining sites in the Gümüşhane province, Türkiye. The concentrations of primordial radionuclides (226Ra, 232Th, and 40K) were measured in samples of andesite, granite, and limestone using a High Purity Germanium (HPGe) detector. Complementary whole-rock geochemical analysis (XRF and ICP-MS) was conducted to understand the geochemical controls on radioactivity concentrations. The results reveal significant heterogeneity in activity concentrations both within and between the two sites. For 226Ra, the Hazine Mağara site exhibited a wider range (2.44–22.57 Bq kg−1) with a higher maximum value compared to Mastra (2.65–13.96 Bq kg−1). Similarly, 232Th and 40K activity concentrations showed considerable variability, often linked to the presence of specific accessory minerals like zircon, monazite, and K-feldspar. Geochemical data indicated that element concentrations (K, U, Th) were generally lowest in limestone and highest in granite, showing a strong correlation with the measured activity concentration values. Radiological risk indices, including radium equivalent activity, absorbed dose rate, annual effective dose equivalent, and excess lifetime cancer risk, were calculated. While values remain below international public health safety limits, localized anomalies were identified. Multivariate statistical methods were used to determine the relationship between the 226Ra, 232Th, 40K, Raeq (Bq/kg), Ig, Hex, D (nGy/h), AEDE (μSv/y), AGDE (μSv/y), and ELCR (×10−5). The study concludes that despite these localized anomalies, both mining areas pose an overall minimum environmental radiation risk, underscoring the necessity for site-specific assessments to ensure safe resource utilization and radiation protection.

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• MakaleYalnız künye2026/r/gumushane/12188
  Mineralogical and geochemical controls on Co-V-Pt-Ni enrichment in manganese mineralization: evidence from the Dilli deposit, Eastern Türkiye

  Gücer, Mehmet Ali; Çimen, Okay; Aktağ, Alican; Keskin, Serdar

  The growing demand for critical minerals driven by the global energy transition and advanced technologies highlights the importance of unconventional metal reservoirs. This study investigates the Ni-, Co-, V-, and Pt-enriched Dilli manganese deposit (Kemaliye-Erzincan, Eastern Türkiye) to constrain the mineralogical, geochemical, and genetic controls on critical metal enrichment in Mn oxide mineralization. An integrated approach combining field observations, petrography, X-ray diffraction (XRD), whole-rock geochemistry, mineral chemistry, and stable C-O isotope analysis was applied to better understand the potential origin of critical mineral enrichments. The mineralization is dominated by Mn4+-bearing oxides, principally pyrolusite and hollandite, accompanied by minor rhodochrosite. High MnO (39-64 wt%) and very low Al2O3 and Fe2O3 contents indicate chemical precipitation with negligible detrital input. Discrimination diagrams and trace-element systematics consistently support a structurally controlled hydrothermal origin. Chondrite-normalized REE patterns display low total REE and very low Nd contents comparable to typical hydrothermal deposits, whereas neutral to slightly positive Ce anomalies and non-chondritic Y/Ho ratios suggest limited oxidative interaction with surface-derived fluids rather than primary marine hydrogenetic growth. Stable C–O isotope compositions of co-genetic calcite are inconsistent with a purely marine depositional environment and indicate precipitation from low-to moderate-temperature hydrothermal fluids. Mineral chemistry reveals strong phase-specific partitioning: hollandite preferentially incorporates V and Ba, whereas pyrolusite is enriched in Ni. Cobalt occurs in both phases, whereas Pt may also be present in both Mn oxide phases, suggesting that trace-element distribution is influenced by both crystallochemical and physicochemical controls. The enrichment of Ni, Co, and Pt is most plausibly linked to hydrothermal fluid circulation through ultramafic units, which likely acted as the primary metal source prior to precipitation. The Dilli deposit thus represents a structurally controlled hydrothermal Mn system enriched in critical metals, emphasizing the exploration relevance of Mn oxide mineral chemistry in identifying alternative sources of critical metals in Türkiye.

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• MakaleAçık Erişim2025/r/gumushane/19644
  Mescitli Formasyonu’na (Gümüşhane, Türkiye) ait kumtaşlarının endüstriyel hammadde olarak kullanım potansiyelinin incelenmesi

  Aliyazıcıoğlu, Şener; Dağ, Serhat; Zeybek, Halil İbrahim; Çavuşoğlu, İbrahim; Gücer, Mehmet Ali; Sipahi, Ferkan; Dokuz, Abdurrahman

  Doğal zenginliklerin ortaya çıkarılması ve yöresel kayaçların ekonomiye kazandırılarak endüstriyel kullanım alanlarının belirlenmesi günümüzde büyük önem taşımaktadır. Bu çalışmada, Gümüşhane’deki Mescitli Formasyonu kumtaşlarının endüstriyel hammadde olarak kullanım potansiyeli araştırılmıştır. Kumtaşları başlıca monokristalin ve polikristalin kuvars, feldispat, volkanik ve tortul kayaç parçaları, opak mineral, kil matriks ve az oranda bağlayıcı karbonat/silis minerali içermektedir. Grovak (psammit) olarak sınıflandırılan kumtaşlarının kimyasal ayrışma indeksi (CIA) parametresine göre alterasyondan çok fazla etkilenmediği belirlenmiştir. Jeoteknik özellikler açısından, ortalama kuru yoğunluk 2.48 gr/cm3, doygun yoğunluk 2.54 gr/cm3, gözeneklilik %6.63 boşluk oranı %7.11, ultrasonik P-dalga hızı 4793 m/sn, tek eksenli basınç dayanımı 103.09 MPa ve dolaylı çekme dayanımı 5,86 MPa olarak belirlenmiştir. Donma-çözünme deneyi ile don kaybı %1.19 olarak belirlenmiş, 600-800ºC sıcaklıklara kadar ısıtılan kumtaşı numunelerinde ortalama 9.8 gr ve 17.9 gr kütle kaybı gözlenmiştir. Aynı sıcaklık koşullarında kumtaşlarının dayanımının sıra ile %7.64 ve %15.17 oranında azaldığı görülmüştür. Hücre Sitotoksisite analizlerinde toksik etkiye rastlanmamıştır. Sonuçlar, kumtaşlarının günlenmeye maruz kalacak alanlarda kullanım için uygun olmadığı, bina içyapı ve dekoratif amaçlı kaplamalarda kullanılabileceğini göstermiştir. Sıcaklık dayanımı ve hücre sitotoksisite analizleri ise kumtaşlarının ızgara taşı olarak kullanılabileceğini ortaya koymuştur.

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• MakaleAçık Erişim2025/r/gumushane/19563
  Granodiyorit atıklarının demir oksitli sırlarda kullanımının araştırılması: estetik ve sürdürülebilirlik perspektifi

  Arıanpour, Aslı Çakır; Gücer, Mehmet Ali; Isiktas, Imre Deniz; Özek, Serap Bedel; Helvacıkara, Fidan Tonza; Sipahi, Ferkan

  Seramik üretimi, doğal hammaddelere dayalı çok aşamalı süreçler gerektirir. Ancak artan çevresel kaygılar ve hammadde kaynakların tükenmesi, alternatif hammadde arayışını ve atık yönetimini seramik endüstrisinin öncelikli konuları haline getirmiştir. Özellikle doğal taş endüstrisinde oluşan atıklar hem çevresel etkilerin azaltılması hem de ekonomik değer yaratılması açısından önemli fırsatlar sunmaktadır. Bu bağlamda, granitoyidik kayaçlar, özellikle demir oksit içeriği sayesinde seramik sırlarında estetik ve işlevsel katkı sağlayabilecek potansiyel bir atık malzeme olarak değerlendirilmiş ve Gümüşhane il merkezindeki bir mermer işletmesinden temin edilen granodiyorit atıklar, demir oksitli sırların renklendirici bileşeni olarak kullanılmıştır. Petrografik analizler sonucunda kayaç numuneleri granodiyorit, diyorit ve granit olarak sınıflandırılmış; özellikle biyotit ve hornblend gibi mafik mineralleri yüksek oranda içeren granodiyorit (H1) örneklerinde toplam Fe₂O₃ oranının %3,96 olduğu belirlenmiştir. Bu nedenle sır formülasyonlarında granodiyorit örneği esas alınmıştır. Beş farklı seramik bünye (kırmızı, şamot, döküm, porselen ve stoneware) üzerine uygulanan granodiyorit katkılı sırlar 1040°C–1100°C aralığında pişirilmiş ve özellikle aventurin etkili yüzeyler elde edilmiştir. Denemeler sonucunda, granodiyorit atıklarının sır yüzey özelliklerini, renklenme karakterini ve estetik niteliklerini olumlu yönde etkilediği gözlemlenmiştir. Elde edilen veriler, bu atık malzemenin seramik sektöründe hem sürdürülebilirlik hem de estetik çeşitlilik açısından değerli bir alternatif sunduğunu göstermektedir.

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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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• MakaleYalnız künye2025/r/gumushane/12314
  Origin and tectonic setting of the carbonate-hosted Kopuz Fe skarn Deposit, Sakarya Zone, NE Türkiye

  Sipahi, Ferkan; Akpınar, İbrahim; Gücer, Mehmet Ali; Kaygusuz, Abdullah; Vural, Alaaddin; Saydam Eker, Çiğdem

  The Kopuz Fe skarn deposit in the eastern Sakarya Zone is genetically associated with the 44–45 Ma Kopuz granitoid. The Fe ores are hosted within the contact zone between this granitoid and Jurassic Lower Cretaceous limestone. The deposit is characterized by both endo- and exoskarn zones, which exhibit a diverse range of minerals including clinopyroxene, plagioclase, amphibole, biotite, garnet, epidote, phlogopite, magnetite, hematite, pyrite, quartz, calcite, actinolite, limonite, and goethite. Magnetite and hematite, accompanied by small amounts of pyrite, are primarily ore minerals. Pyroxene types observed in the mineralization include diopsidic hedenbergite in the endoskarn zone and diopside in the exoskarn zone. Plagioclase in the endoskarn zone vary from oligoclase to Labrador in composition, which transition towards Na-rich plagioclase and orthoclase in the ore-bearing exoskarn zone. Amphiboles, primarily calcic in nature, are classified as Mg-hornblende and actinolite, with low F and Cl contents, indicating minimal F enrichment during Fe-skarn formation. Garnet is characterized by andradite in the exoskarn zone close to the endoskarn and grossular-andradite in the distal exoskarn zone. The increase of Ad/Gr ratios in zoned garnet indicate an increasing ƒO2 value outward from it. Considering that rare pyrite occur together with magnetite and hematite, we suggest that the deposit formed under conditions of low ƒS2 and high ƒO2 conditions. The homogenization temperature and salinity of the fluid inclusions in quartz from the exoskarn zone vary from 224 °C to 349 °C and 4.18 % (wt% NaCl equiv.), respectively. The oxygen isotope composition (5.10 ‰ to 7.86 ‰) of the fluids in equilibrium with magnetite and quartz minerals in the exoskarn zone supports a magmatic fluid origin. The oxygen isotopic signatures of epidote and amphibole further indicate a minor interaction with an additional source, likely meteoric waters. The sulfur isotope composition of pyrite (2.3 ‰) is consistent with a magmatic sulfur source. In summary, the middle Eocene-aged Kopuz Fe skarn deposit occurred a shallow depth within a magmatic arc, where oxidized conditions predominated.

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• MakaleAçık Erişim2025/r/gumushane/10323
  Geochronological and isotopic data from the adakitic Dodurga Pluton (Central Pontides, N Turkiye): new insights for the geodynamic evolution of the northern Neotethys

  Çimen, Okay; Gücer, Mehmet Ali; Simonetti, Antonio; Karaoglan, Fatih

  The Dodurga Pluton is located within the Central Pontides (northern Turkiye), has a SW-NE elongation, and consists of granodiorite and dacite porphyry. Previous studies have suggested that this pluton is Triassic in age, and its whole-rock geochemical systematics is consistent with that from adakitic magmatic occurrences rather than the classic arc granitoid suite. This study reports for the first time in situ/whole-rock radiogenic isotopic (Sr, Nd, and Pb) and mica/amphibole Ar-Ar age data to evaluate better its petrogenetic/geodynamic evolution and the chemical nature of mantle source(s). Unlike previous data, combined new in situ zircon U-Pb yield Late Cretaceous crystallization ages of 84.2 +/- 0.9 Ma and 86.9 +/- 0.9 Ma, and the Ar-Ar age data along with apatite fission track measurements suggest magma cooling extending to 82.3 +/- 0.4 Ma and 85.4 +/- 0.4 Ma, respectively. The apatite fission track (AFT) dating results also reveal that this pluton was buried at a depth of 2.5-3 km following a fast-cooling period during the Late Cretaceous and cooled/exhumed over similar to 2 km during the Middle-Late Miocene (15-10 Ma) in a slow cooling phase. The overall data reported here suggest that the Dodurga Pluton represents melts derived from an enriched/metasomatized mantle source that interacted with lower crustal mafic rocks in an active continental margin as a result of northward subduction of the northern branch of the Neotethys Ocean.

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• MakaleAçık Erişim2024/r/gumushane/10642
  Revisiting the depositional age and provenance characteristics of metasedimentary rocks from the basement units in the Central Pontides (N Turkey): New constraints for tectonic evolution of the southern Black Sea region

  Cimen, Okay; Gucer, Mehmet Ali; Akal, Cueneyt; Goncueoglu, Mehmet Cemal; Arslan, Mehmet; Simonetti, Antonio; Karaoglan, Fatih

  The pre -Jurassic tectonic evolution of the Central Pontides in northern Turkey is still poorly understood due to the lack of detailed geochemical and geochronological data from the basement units. Therefore, this study reports for the first time combined whole rock geochemistry, trace element data and U-Pb ages for detrital zircons, and Ar-Ar geochronological data from the metasedimentary rocks of the Devrekani Massif, Geme Complex, and the Serve & ccedil;ay Unit to better understand their provenance, depositional age characteristics, and tectonic evolutions. The detrital zircon U-Pb data of metasedimentary units from the Devrekani Massif, Geme Complex, and the Serve & ccedil;ay Unit yield ca. 191, 185 and 298 Ma maximum depositional ages (youngest age peaks), respectively. The Devrekani Massif is dominated by Permo-Carboniferous-aged detrital zircons (67 %), whereas Neoproterozoic and Devonian -aged detrital zircons are more common in the Geme Complex (47 %) and the Serve & ccedil;ay Unit (53 %). These distinct age distributions clearly indicate that the Devrekani Massif may has been deposited in a dissimilar location compared to the Geme Complex and the Serve & ccedil;ay Unit. Furthermore, in contrast to the Devrekani Massif, the source area of the metasedimentary rocks from the Geme Complex is comparable with that of the Serve & ccedil;ay Unit. Lastly, the obtained detrital zircon U-Pb and mica Ar-Ar ages suggest that the Devrekani Massif and the Geme Complex were deposited and metamorphosed during the Early and Middle Jurassic, respectively. The Serve & ccedil;ay Unit was deposited and metamorphosed in the Permian.

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• MakaleAçık Erişim2024/r/gumushane/20019
  Erken Eosen yaşlı adakitik andezitler (Gümüşhane, KD Türkiye) içerisindeki mikrogranüler anklavların jeokimyasal karakteristikleri

  Çimen, Okay; Gücer, Mehmet Ali; Güner, Abdulkadir Murat

  Doğu Sakarya Zonu’ndaki (KD Türkiye) erken Senozoyik magmatizması, bölgesel tektonomagmatik gelişime dair önemli veriler sağlamaktadır. Bölgede, adakit veya adakitik intrüzif/ekstrüzif kayaçlar Geç Paleosen’den Pliyo-Kuvaterner döneme kadar yaygın olarak gözlenmektedir. Çalışma alanında, Erken Eosen adakitik andezitler, genellikle 10 km2’den küçük mostralar halinde gözlenmektedir. Adakitik bileşimli bu andezitler bol miktarda mikrogranüler anklav içermekte olup bu çalışmada petrografik/jeokimyasal özellikleri ve ana kayaç ile olan petrolojik ilişkileri irdelenmiştir. Ana kayaca kıyasla nispeten bazik bileşimli anklavlar, küreselden elipsoidala kadar değişen şekillerde ve birkaç cm ile 20 cm arasında değişen boyutlarda gözlenmektedir. Anklavlar mikrolitik yer yer porfirik dokulu olup başlıca plajiyoklas, hornblend, klinopiroksen, ortoklas ve opak minerallerden meydana gelmektedir. Gerek petrografik gerekse petrokimyasal özellikleri anklavların bazaltik andezit türünde olduğunu ve sub-alkalin bir magmadan türemiş olabileceğini göstermektedir. Ana ve iz element değişimleri, gelişimlerinde fraksiyonel kristallenmenin etkili olduğunu ve plajiyoklas, piroksen, hornblend, magnetit ve apatit ayrımlaşmasının büyük ölçüde rol oynadığını göstermiştir. Anklav ve ana kayaçların benzer iz element davranışları felsik ve mafik magmaların karışması esnasındaki etkileşim süreçlerini işaret edebilir. NTE dağılımları ise gelişimlerinde hornblend fraksiyonlaşmasının önemli rol oynadığını, buna karşılık plajiyoklas ayrımlaşmasının etkili olmadığını işaret etmektedir. Petrokimyasal veriler, anklavların ana magmasının, kuzey Neotetis Okyanusu’nun tamamen kapanmasından hemen sonra; genleşmeli tektonik rejimin başlangıç aşamalarında, amfibol-eklojit fasiyesi koşullarında okyanusal bazaltların kısmi erimesi ile üretildiğini göstermektedir.

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