Sürdürülebilir Kalkınma Amaçları
Yayınlar
- MakaleYalnız künye2018Tracing provenance and chemical weathering changes in Ankara Stream sediments, central Turkey: Geochemical and Sr–Nd–Pb–O isotopic evidence
Saydam Eker, Çiğdem; Sipahi, Ferkan; Gümüş, Mustafa Kemal; Özkan, Özay
This study aims to analyze the changes in sediment provenance through the geochemical and Sr–Nd–Pb–O isotopic composition of the Ankara Stream bed and overbank sediments (ASBS and ASOS) and to examine the weathering and sediment transport processes in response to step climate variability. Major, trace, and rare earth elements, as well as Sr–Nd–Pb–O isotopic composition, exhibit generally similar variations for the investigated samples. These sediments have relatively high εNd(0) values and low 87Sr/86Sr ratios. Similar Pb isotopic ratios also characterize these sediments but have slightly different δ18O isotope values with relatively higher δ18O isotope values in the ASBS and lower δ18O isotope values in the ASOS samples. Chemical indices indicate low–moderate chemical weathering in the step-dominated climate. The low average Zr/Sc and Zr/Nb ratios indicate that such geochemical change was dominated by the composition of the source rocks but not sedimentary recycling with zircon enrichment, reflecting first-cycle deposit. Low radiogenic 87Sr/86Sr ratios and negative εNd(0) values indicate that the investigated sediments are relatively derived from young magmatic provinces, which are intermediate sources. Finally, the findings show that the geochemical compositions of the ASBS and ASOS were dominated by the composition of the source materials that originate from Galatia province and Late Cretaceous- Early Tertiary volcanic rocks in central Anatolia. Reasonable semiarid to arid climatic conditions are observed in the region. Active tectonism, increased erosion, and the investigated sediments are also transported rapidly to the stream channel without chemical alteration, and the sediments are the first-cycle products.
- MakaleYalnız künye2017Kalınçam (Tonya-Trabzon, KD Türkiye) Yöresi Geç Kretase Yaşlı Volkanitlerin Jeokimyası ve Petrojenezi
Sipahi, Ferkan
Doğu Karadeniz Bölümü'nde, Kalınçam (Tonya, Trabzon) yöresi volkanitleri Geç Kretase yaşlı olup, tabanda bazalt, andezit ve piroklastitleri, bunları sırasıyla dasit, riyodasit ve piroklastitleri, andezit ve piroklastitleri ve tekrar dasit ve piroklastitleri izlemektedir. Taban bazalt ve andezitlerinde vesiküler, porfirik ve boşluklu doku; mineralojik olarak bazaltta plajiyoklas; andezitte ise plajiyoklas ve daha az olarak amfibol mineralleri bulunmaktadır. Dasit ve riyodasitik kayaçlar mikrogranü porfirik ve camsı porfirik dokuda olup, plajiyoklas, kuvars ve hornblend minerallerinden oluşmaktadır. Bunların üzerine gelen andezitler camsı-mikrolitik-porfirik dokuda ve plajiyoklas ile hornblendden ibaret bir bileşime sahiptirler. En üstte bulunan dasitik kayaçlar mikrogranü porfirik ve camsı porfirik dokuda; plajiyoklas, kuvars ve hornblend minerallerinden oluşmaktadır. İncelenen volkanitler kalk-alkali-geçiş? özelliğe sahip olup, yüksek büyük iyon yarıçaplı element (BİYE) ve düşük yüksek çekim alanlı element (YÇAE) içerikleri ve yüksek BİYE/YÇAE oranları ile yitim ilişkili kayaçların jeokimyasal özelliğini yansıtmaktadır. Kondirite normalleştirilmiş nadir toprak element dağılımları (LaN/LuN=3.11-13.10) Kalınçam yöresi volkanitleri için benzer kaynağa işaret eden orta derece zenginleşme göstermektedir. 87Sr/86Sr(i)değerleri 0.70727 ilâ 0.70779 arasında, 143Nd/144Nd(i) değerleri ise 0.512318 ilâ 0.512656 arasında değişmektedir. İncelenen volkanik formasyonlardaki kayaçların bazik-asidik karakterde olması hem yitimden etkilenmiş manto hem de kabuk kaynaklarının olası olduğunu göstermektedir.
- Proje2017Granitoidlere (Gümüşhane, Kd Türkiye) Bağlı Gelişen Skarn Cevherleşmelerinin Jeolojisi, Jeokimyası Ve Jeokronolojisinin Araştırılması
Saydam Eker, Çiğdem; Kaygusuz, Abdullah; Vural, Alaaddin; Sipahi, Ferkan
Kopuz Fe ve Karadağ Fe-Cu skarn cevherleşmeleri Gümüşhane'nin (KD Türkiye) kuzeybatısında bulunmaktadır. Kopuz ve Karadağ (Torul, Gümüşhane) çevresinde granitoyid, tortul ve volkanik kayaçlar yer almaktadır. Kopuz Granitoyidi 79.9 My, Karadağ Granitoyidi 44 My yaşlı olarak belirlenmiştir. Kopuz?da kireçtaşı ile volkanitlere 79.9 My yaşlı granitoyidin sokulumu ile dokanak metamorfizması ve skarn zonu gelişmiştir. Kopuz Fe skarn cevherleşmesine sebep olan granitoyid yüksek K?lu kalk-alkali karakterde ve metalimünyum özellikte olup yay granitlerine benzerlik göstermektedir. Granodiyoritten kireçtaşına doğru endo- ve ekzoskarn zonları gelişmiştir. Skarn zonunda piroksen, granat, biyotit-flogopit, amfibol, epidot, kuvars, kalsit ve aktinolit mineralleri oluşmuştur. Skarn zonunda piroksen türü diyopsitik hedenberjit ve diyopsit, granat türü andradit ile grossular andradittir. Kopuz Fe skarn cevherleşmesinde cevher minerallerinin parajenezi manyetit, pirit ve hematit şeklinde belirlenmiştir. Karadağ?da 44 My yaşlı granitoyidlerin Geç Kretase yaşlı kireçtaşı ve volkanitlere sokulumu sonucu skarn cevherleşmesi oluşmuştur. Karadağ Fe-Cu skarn cevherleşmesine sebep olan granitoyid yüksek-orta K?lu kalk-alkali karakterde olup kuvars monzonit, granodiyorit ve kuvars porfirler peralimünyum; diyoritler metalimünyum özellikte ve genelikle yay granitlerine benzerlik göstermektedir. Karadağ Fe-Cu skarn cevherleşmesinin ekzoskarn zonundaki skarn mineralleri piroksen, granat, epidot, kuvars ve kalsittir. Karadağ Fe-Cu skarn cevherleşmesinde piroksenler diyopsit olup çok az hedenberjit, vollastonit veya johansinit bileşiminde, granatlar ise andradit ile grossular andradittir. Cevher minerallerinin parajenezi manyetit, pirit, hematit ve kalkopiritten oluşmaktadır. Kopuz Fe skarn cevherleşmesindeki granitoyidlerdeki apatit ve zirkon termometre hesaplamalarında yerleşim sıcaklığı 758-907 ºC arasındadır. Kopuz Fe skarn cevherleşmesinin ekzoskarn zonunda andradit-diyopsit çiftinin mineral kimyasından 344-434 oC arasında sıcaklık değerleri belirlenmiştir. Karadağ Fe-Cu skarn cevherleşmesi çevresindeki granitoyidlerde apatit ve zirkon termometresi yerleşim sıcaklığı 668-1021 ºC arasında hesaplanmıştır. Karadağ Fe-Cu skarn cevherleşmesinde ekzoskarn zonunda andradit-hedenberjitik diyopsit ve grossular andradit-diyopsit çiftinin mineral kimyasından 412- 503 oC arasında sıcaklık değerleri belirlenmiştir. Kopuz Fe ve Karadağ Fe-Cu skarn cevherleşmelerinde ekzoskarn zonu kuvars ve kalsit mineralleri sıvı kapanımları birincil ve Tip I kapanımlardır. Kopuz?da homojenleşme sıcaklığı 224-349 °C ve tuzluluk % 4.18 (NaCl eşdeğeri tuzluluk); Karadağ?da ise sırasıyla 175-430 oC ve % 0.2-14.8 (NaCl eşdeğeri tuzluluk) arasında belirlenmiştir. Sıvı kapanım verileri skarn kökeni desteklemekle birlikte nispeten farklı iki sıvının izotermal karışımı ile soğumanın mineral çökeliminde etkili olduğunu belirtmektedir. Kopuz Fe ve Karadağ Fe-Cu skarn cevherleşmelerinde piritin manyetit ve hematitle birlikte az miktarda olması, Kopuz Fe skarn cevherleşmesindeki piritin S-izotop değerinin dar bir aralıkta değişmesi ve magmatik kaynağı göstermesi her iki cevherleşmeyi oluşturan sıvıların başlangıçta kükürt içeriğini desteklemekte olup düşük ?S ve yüksek ?O2 ortam şartlarında oluştuğunu belirtmektedir. Kopuz Fe skarn cevherleşmesinde skarn mineralleri olarak diyopsitik hedenberjit ve diyopsit, andradit ve grossular andradit, epidot, bol manyetit, hematit ve çok az piritin olması; Karadağ Fe-Cu skarn cevherleşmesinde ise diyopsit, andradit ve grossular andradit, epidotun, manyetit ve hematitce zengin, çok az kalkopirit ve piritin varlığı; sıcaklıkların 200-500oC arasında olması; her iki cevherleşmeyi oluşturduğu düşünülen sıvıların tuzluluğunun magmatik sıvıları belirtmesi; oksijen ve karbon izotop verilerinin magmatik kökeni desteklemesi, cevherleşmelerin magmatik yayda, başlangıçta kükürtlü daha sonra oksitli şartların egemen olduğu sığ sokulum oluşumunu işaret etmektedir.
- MakaleYalnız künye2017Evaluation of potentially toxic element contents and Pb isotopic compositions in Ankara Stream sediments within an urban catchment in central Turkey
Eker, Çiğdem Saydam; Sipahi, Ferkan; Özkan, Özay; Gümüş, Mustafa Kemal
This study aimed to interpret the spatial distribution, enrichment factor (EF), and geo-accumulation of potentially toxic elements in the bed sediments (ASBS) and Pleistocene-aged overbank sediments (ASOS) of the Ankara Stream in Turkey. The potential toxic pollution of the investigated potentially toxic elements was defined by evaluating the EF, geo-accumulation index (Igeo), and Pb anthropogenic contribution. The distributions of As, Ni, and Co in the analyzed sediments were uniform in the ASBS and ASOS along the length of the stream. The EF and Igeo values indicated that ASBS and ASOS were significantly polluted by As and Ni and moderately polluted by Co, Zn, and Cu. ASBS was locally strongly polluted by Pb and Cd. Pb anthropogenic contribution was estimated at an average of > 100% in the ASBS and ASOS. The potentially toxic element levels and distribution patterns revealed that industrial activities, gasoline combustion, vehicular emission, phosphate fertilizers and natural sources were probable causes of metal pollution in Ankara Stream sediments. These potentially toxic elements were transported by atmospheric conditions and stream water. The potentially toxic elements in Ankara Stream increased with each passing day and were important in evaluating the potential toxicity risks to living organisms. Thus, suitable measures should be taken to ensure appropriate treatment of wastewater before toxic residues are disposed into the nearby stream. Chimney filter, treatment plants, and appropriate technology should be used in the organized industrial zone to prevent atmospheric pollution.
- MakaleYalnız künye2017Formation of the Eğrikar (Gümüşhane) Fe–Cu skarn type mineralization in NE Turkey: U–Pb zircon age, lithogeochemistry, mineral chemistry, fluid inclusion, and O-H-C-S isotopic compositions
Sipahi, Ferkan; Akpınar, İbrahim; Eker, Çiğdem Saydam; Kaygusuz, Abdullah; Vural, Alaaddin; Yılmaz, Meltem
The Eğrikar Fe–Cu skarn type mineralization is located approximately 100 km NW of Gümüşhane in NE Turkey. Geochemical analyses of diorite, which is thought to cause skarn, indicate medium K calc-alkaline (1.3 to ~ 2.3 wt% K2O), metaluminous to peraluminous (A/CNK = 0.76 to 1.13) and resembles a continental arc granite. The age of U–Pb zircon obtained from diorite is 42.3 ± 1.0 Ma, which reflects the age of skarn metasomatism after intrusion into Late Cretaceous sandy carbonates. Skarn formation zones are recognized as endo- and exoskarn. The endoskarn zone mainly consists of pyroxene with hedenbergite (Di4.31–28.14Hd59.29–80.82Jo5.0–35.55) at prograde stage. Mn content of pyroxene increases a slight from endo to exoskarn. Pyroxene is replaced by epidote and hornblende at the retrograde stage. The exoskarn zone comprises garnet with andradite (Ad91-99Gr01–07) and grossular-andradite (Ad44-95Gr05–54), epidote and quartz as silicate minerals, and magnetite and hematite as ore minerals. Magnetite is the abundant ore mineral and is accompanied by chalcopyrite and minor pyrite at retrograde stage. On the basis of fluid inclusion values of minerals, the temperature range for hedenbergite in endo-exoskarn is 350 °C–425 °C, for epidote in exoskarn is 365 °C–376 °C, and for quartz in exoskarn 200 °C–380 °C. NaCl equivalent salinity for hedenbergite 6.88–10.73 wt% and for quartz is 3.9–15.38 wt. The δ18O values of hedenbergite is 4.1 to 4.7‰ and for garnet 3.4‰ at prograde stage, for epidote 7.9–9.2‰, for magnetite 1 to 4.4‰, for hematite − 2.9 to − 1.6‰ and for quartz range between 8.5‰ and 15.2‰. The δ18O value of epidote suggests that oxygen is a magmatic fluid whereas hedenbergite, garnet, quartz and magnetite show the mixing of magmatic and meteoric fluids. In addition, the C isotope values (− 3.2 to 2.8‰) of calcite and marble in Eğrikar Fe–Cu skarn reflect those of metamorphic, and skarns. Based on oxygen isotope data from mineral pairs, the retrograde skarn formation is characterized by epidote–magnetite assemblage formed at 255 °C–438 °C. Fluid oxygen isotope compositions of magnetite and epidote pairs of the exoskarn skarn zone indicate a mixing of magmatic and meteoric fluids with narrow δ18O values between 7.17‰ and 8.9‰. The δ34S values of the pyrites exhibit a narrow range of 3‰ and 4.4‰, thereby indicating that sulfur were probably leached from magmatic rocks. Based on the field and laboratory observation, mineral chemistries, fluid inclusion studies and isotope composition analysis, it is suggested that the Eğrikar Fe–Cu skarn mineralization occurs in a magmatic origin fluids being initially under reduced conditions, subsequently under oxidized conditions, and at shallow depth.
- Proje2016Ankara Çayı (Ankara, Türkiye) Dere Yatağı Sedimanları ve Eski Alüvyonlarının Jeokimyasal ve İzotopik Farklılıkları
Eker Saydam, Çiğdem; Özkan, Özay; Sipahi, Ferkan
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- Proje2016Egrikar (Torul, Gümüshane, Kd Türkiye) Skarn Cevherlesmesinin Mineral Kimyası, Sıvı Kapanım Ve Duraylı Izotop Bilesimlerinin Arastırılması
Saydam Eker, Çiğdem; Kaygusuz, Abdullah; Vural, Alaaddin; Sipahi, Ferkan
Egrikar Fe?Cu skarn yatagı Gümüshane?nin (KD Türkiye) yaklasık 100 km kuzeybatısında bulunmaktadır. Inceleme alanı, tabanda Geç yaslı Kretase Egrikar Monzograniti, bunun üzerine sırasıyla andezit, kireçtası içeren dasit ve hornblenli andezitten olusmaktadır. Bu kayaçlar Orta Eosen yaslı Erik Granitoyidi (granodiyorit ve diyorit) tarafından kesilmektedir. Andezitler, porfirik, camsı ve bosluklu dokuda olup plajiyoklaslardan olusmaktadır. Dasitik kayaçlar porfirik dokuda olup, baslıca kuvars, plajiyoklas, biyotit ve opak minerallerden olusmaktadır. Kireçtasları ise yer yer mermere dönüsmüs ve kristalize olmustur. Hornblendli andezitler mikrogranü porfirik ve glomeroporfirik dokulu olup ve plajiyoklas, hornblend, biyotit ve kuvars minerallerini içermektedir. Geç Kretase yaslı Egrikar monzograniti baslıca plajiyoklas, kuvars, ortoklas, biyotit ve muskovitten olusmaktadır. Orta Eosen yaslı Erik Granitoyidi ise granodiyorit ve diyorit bilesimli olup plajiyoklas ve hornblend minerallerinden ibarettir. Egrikar Fe-Cu skarn yatagındaki volkanitler kalk-alkali karakterdedir. Egrikar Monzograniti orta K?lu kalk-alkali bilesimde olup peralüminyum karakterdedir. Egrikar Monzogranitinin iz element karakteristikleri, genel olarak yay granitlerine benzerlik gösterirler. Erik Granitoyidi orta K?lu kalk-alkali özellikte ve metalüminyum karakterdedir. Egrikar Fe-Cu skarn sahasında Fe-skarn ile iliskili Erik Granitoyidi çarpısma sonrası meydana gelmistir. Erik Granitoyidi?nin kireçtasına sokulumu sonucu dokanak metamorfizması olusmus ve skarn zonu gelismistir. Granitoyidden kireçtasına dogru endo- ve ekzoskarn zonlarının olustugu belirlenmistir. Skarn zonunda piroksen, granat, epidot, kuvars, kalsit ve aktinolit-tremolit skarn minerallerini olusturmaktadır. Skarn zonunda piroksen türü hedenberjit, granat türü andradit ile grossular andradittir. Egrikar Fe-Cu skarn yatagının cevher minerallerinin parajenezi manyetit, pirit, hematit, kalkopirit, altın ve nabit bakırdan olusmaktadır. Ikincil cevher mineralleri olarak götit, limonit, dijenit, malakit, azurit, bornit ve lepidokrozit belirlenmistir. Egrikar Fe-Cu skarn yatagındaki endo-ekzoskarn zonunda hedenberjit, epidot ve kuvars minerallerinde yapılan sıvı kapanım çalısmalarında, sıvı kapanımlar birincil ve Tip I kapanımlar olarak sınıflandırılmıstır. Hedenberjit, epidot ve kuvarslarda yapılan sıvı kapan çalısmalarında sıcaklık 200-425 ve tuzluluk % 2.7-15.38 arasında olup skarn kökeni desteklemektedir. Hedenberjit, granat, manyetit, epidot, amfibol, kuvars ve pirit minerallerinden belirlenen oksijen ve kükürt izotop degerleri dar bir aralıkta degismekte ve magmatik kökeni desteklemektedir. Endo-ekzoskarn geçis zonu için hedenberjit-granat çiftinin mineral kimyasından 446-377 oC sıcaklık ve ekzoskarn zonunun termodinamik sartları manyetitepidot çiftinin izotop bilesiminden 255-438oC olarak belirlemistir. Sıcaklık degisimine baglı olarak düsük kükürtlü, nispeten yüksek oksitli magmatik sıvılardan itibaren mineral çökelimi gerçeklesmistir. Egrikar Fe-Cu skarn yatagında; piroksenin hedenberjit, granatın andradit ve grossular andradit türünde, bol manyetit, hematit ve çok az pirit ve kalkopirit bilesimli olması, sıvı kapanım sonucu elde edilen sıcaklık ve tuzluluk verileri ile skarn minerallerinin duraylı izotop bilesimleri bu yatagın magmatik sıvılardan baslangıçta düsük sülfürlü sonradan yüksek oksitli sartlar altında sıg sokulum sonucu olustugunu göstermektedir.
- MakaleYalnız künye2016U–Pb zircon chronology and petrogenesis of Carboniferous plutons in the northern part of the Eastern Pontides, NE Turkey: Constraints for Paleozoic magmatism and geodynamic evolution
Kaygusuz, Abdullah; Arslan, Mehmet; Sipahi, Ferkan; Temizel, İrfan
Numerous intrusive rocks of varying ages and compositions exist in the Paleozoic to Tertiary periods in the Eastern Pontides. Carboniferous intrusive rocks are commonly observed in the southern part of the Eastern Pontides. The nature of the rocks in the northern part of the region has not been determined because of Upper Cretaceous and Tertiary volcano-sedimentary units. Whole-rock geochemical, isotopic and geochronological data obtained from five different mapped granitoid bodies located in the northern part of the Eastern Pontides allow for the proper reconstruction of Carboniferous magmatism and the geodynamic evolution of the region. According to laser ablation ICP-MS U–Pb zircon dating, the Özdil, Soğuksu, Seslikaya, Kızılağaç and Şahmetlik plutons have similar 206Pb/238U vs. 207Pb/235U concordia ages of 340.7 ± 1.8 Ma and 323.1 ± 1.5 Ma, 348.4 ± 1.6 Ma, 335.4 ± 1.4 Ma, 337.2 ± 0.6 Ma and 334.5 ± 1.4 Ma, respectively. The aluminium saturation index (ASI) values of all of the samples from the plutons are between 1.0 and 1.32, which indicate peraluminous melt compositions. The plutons have SiO2 contents between 59 and 79 wt.% and show low- to high-K calc-alkaline characteristics. The plutons are enriched in large-ion lithophile and light rare earth elements and are depleted in high-field strength elements. Chondrite-normalized rare earth element patterns are characterized by concave-upward shapes and pronounced negative Eu anomalies, with LaCN/YbCN = 1.9–46.8 and EuCN/Eu* = 0.19–1.76. The studied plutons show considerable variations in 87Sr/86Sr(i) (0.70255 to 0.71006) and εNd(i) values (− 4.8 to − 7.1), as well as Nd model ages (1.15 to 2.47 Ga). The Pb-isotopic ratios are 206Pb/204Pb = 17.11–18.60, 207Pb/204Pb = 15.58–15.64 and 208Pb/204Pb = 36.95–38.62. The crystallization temperatures of the melts range from 676 to 993 °C, as determined by zircon and apatite saturation thermometry. These data suggest that the Carboniferous granitic magmas were produced by the partial melting of meta-mafic to meta-felsic lower crustal source rocks, with minor contributions from the mantle. Collectively, these rocks represent a late stage of Hercynian magmatism in the northern part of the Eastern Pontides.
- MakaleYalnız künye2016Concentrations of elements in Lias coals from the eastern Black Sea Region, NE-Turkey
Eker, Çiğdem Saydam; Akpınar, İbrahim; Sipahi, Ferkan; Yapıcı, Ejder
ABSTRACT: The element contents and organic matter-element relation between Lias-aged coals exposed in four fields in Gümüşhane and Bayburt were investigated. In general, fixed carbon and gross calorific values of the Edire and Balkaynak coals are higher than Güvercinlik and Çerçi coals. The highest ash yields were observed in the Çerçi coals. The concentrations of Mg, P, Ca, Mo, Y, Ni, U, Zn, Ga, Ba, W, Sr, Ta, and Be of the analysed coals are positively correlated with ash yield, indicating an organic affinity. The Lias-aged coals located in Gümüşhane and Bayburt are low-rank coals.
- MakaleYalnız künye2016Investigation of the quality and physical-geochemical characteristics of the drinking water in Gümüşhane (Turkey) city central
Sipahi, Ferkan; Uslu, Sultan
The physical (turbidity, color, smell, taste, pH, and conductivity) and geochemical properties (Ca, Mg, Na, Fe, Mn, Al, K, Cl−, HCO3 −, SO4 2−, Fe, Cu, Co, Ni, Zn, Cd, Pb, and Cr) of the drinking water in Gümüşhane city center were determined. This city center constitutes the study area. The pH levels of the water samples ranged from 6.3 to 8.2, and their conductivities ranged between 240 and 900 μS. These findings were concordant with the drinking water standards of the Turkey Standard Institute and the World Health Organization. The hardness of the water samples in the study area was between 18.1 and 115.1 °Fr. These samples were classified as extremely hard, hard, and quite hard. In addition, an assessment using the criteria for Inland Surface Water Classification indicated that considering certain parameters (pH levels, amount of Na, SO4 2−, Fe, Mn, Al, Co, Ni, Cu, and Cr), the samples belonged to class I (high quality) water. When Cl− amount and conductivity were considered, the samples belonged to the first and second classes (less polluted) of water. The water in the study area was generally classified as carbonated and sulfated (Ca + Mg > Na + K) water classes. This water contained more weak acids than strong acids (HCO3 − + CO3 2− > Cl− + SO4 2−). The pH levels (6.3–8.2) of the water in the study area were unrelated to the varying concentrations of metals in the water. Elements such as Fe, Ni, Cd, Pb, Zn, and Cu increase in the water through the water–rock interaction in the area in which water rises or through the mixture of water with either mine or industrial wastes. In addition, several water samples belonged to an acceptable water class for drinking and usage.
- MakaleYayıncıda açık erişim2016Organic geochemistry and element distribution in coals formed in eocene lagoon facies from the Eastern Black Sea Region,NE Turkey
Saydam Eker, Çiğdem; Akpinar, İbrahim; Sipahi, Ferkan
The amount and type,the inorganic element content,and the maturity of organic materials of Eocene coals,shaly coals,and coaly shales exposed in the Gümüşhane and Bayburt districts of the Eastern Black Sea Region of Turkey were investigated. The depositional environments and hydrocarbon potentials were also interpreted. The total organic carbon concentrations in the studied samples ranged from 0.50% to 63.08%. The samples from Özyurt,Kayadibi,and Tarhanas contained types II and III kerogen,and those from Sökmen and Manas contained type III kerogen. The samples contained Co,Cs,Ga,Hf,Th,U,Y,Mo,Be,Cd,Sb,and La,with average values similar to those of standard brown coals. The samples showed average contents of Co,Ga,Nb,Rb,V,Y,Cu,Pb,Zn,As,Be,and Se,similar to those of other Turkish coals. The sediment source of Eocene samples in the five areas was characterized by rocks with intermediate or mafic geochemical characteristics. The terrigenous/aquatic ratio of coal and shaly coal samples of the areas in question is >1. The sterane distribution was C29 > C28 > C27 and C29 > C27 > C28 for the Özyurt and Tarhanas areas,respectively. The average Tmax values for samples are between 424 °C and 460 °C. For samples Oz-1 and Ta-2,22S/(22S + 22R) homohopane (C32) ratios are 0.48 and 0.61,respectively; 20S/(20S + 20R) sterane (C29) ratios are 0.18 and 0.53,respectively; and Ts/(Ts + Tm) ratios are 0.015 and 0.64,respectively. The Pr/Ph ratios of the samples are >3. The studied samples have low sterane/hopane and high (C19+C20)/C23) ratios without anoxic biomarkers (17α(H)-28,30-bisnorhopane). Based on these data,the coals,shaly coals,and coaly shales were probably deposited under an oxic-suboxic mixture of marine and terrestrial environment conditions; these materials contain terrestrial organic matter and cannot generate hydrocarbon.
- MakaleYalnız künye2014LA-ICP MS zircon dating, whole-rock and Sr-Nd-Pb-O isotope geochemistry of the Camiboǧazi pluton, Eastern Pontides, NE Turkey: Implications for lithospheric mantle and lower crustal sources in arc-related I-type magmatism
Kaygusuz, Abdullah; Arslan, Mehmet; Siebel, Wolfgang; Sipahi, Ferkan; Ilbeyli, Nurdane; Temizel, Irfan
Late Cretaceous I-type plutons are widespread in the Eastern Pontides, NE Turkey. The studied Camiboǧazi pluton is a composite pluton consisting of diorite, tonalite, monzodiorite, monzonite, quartz monzonite, granite, and mafic microgranular enclaves (MMEs). Laser ablation ICP-MS U-Pb dating of zircon yielded crystallization ages of 76.21±0.79Ma, 75.65±0.50Ma, 75.04±0.83Ma, and 74.73±0.86Ma for diorite, monzodiorite, monzonite, and granite, respectively. The rocks of the pluton have I-type, high-K to shoshonitic and metaluminous character, displaying whole-rock geochemical features of arc-related granites. They are enriched in large-ion lithophile and light rare-earth elements, and depleted in high-field-strength elements. Major element variations can be attributed to fractionation of plagioclase, clinopyroxene, hornblende, and Fe-Ti oxides. The rocks show considerable variation in 87Sr/86Sr(i) (0.70498 to 0.70622), εNd(i) (-2.79 to -0.36), δ18O values (+6.3 to +11.4) and Nd model ages (TDM) (0.81Ga to 1.26Ga). Besides, they have (206Pb/204Pb)=18.44-19.09, (207Pb/204Pb)=15.64-15.69, and (208Pb/204Pb)=38.37-38.89. Although isotope signatures of the mafic microgranular enclaves (MMEs) (87Sr/86Sr(i)=0.70551 to 0.70622; εNd(i)=-2.9 to -1.23; δ18O=+8.3 to +9.7) are largely similar to the host rocks, MMEs are characterized by relatively high Mg-numbers (32-36), low contents of SiO2 (52-56wt.%) and low ASI (0.7-0.9). Estimated crystallization temperatures for the rocks of the pluton range from 735±58°C to 844±24°C and a shallow intrusion depth (<10km) is estimated from Al-in-hornblende thermobarometry. Whole-rock geochemical and isotopic data suggest magma generation by dehydration melting of an amphibolite-type lower crustal component with additional input of a subcontinental lithospheric mantle component. Furthermore, Sr-Nd isotope mixing model reveals ~30% to 40% lower crustal magma contribution to the mantle component.
- MakaleYalnız künye2014Geochemical and Sr-Nd isotopic characteristics of Murgul (Artvin) volcanic rocks in the Eastern Black Sea Region (Northeast Turkey)
Sipahi, Ferkan; Sadiklar, M. Burhan; Şen, Cüneyt
The studied volcanic rocks are footwall and hanging wall dacites from the Murgul mine and the surrounding area. Moreover, the hanging wall dacites contain enclaves. Footwall dacite contains biotite, whereas hanging wall dacitic rocks contain hornblende as a ferromagnesian mineral. The enclaves in the hanging wall dacite have sizes that range from 1cm to 20cm and contain hornblende as a ferromagnesian mineral. The volcanic rocks show tholeiitic and transitional affinities. They are rich in large ion lithophile element and light rare earth element with pronounced depletion of high field strength elements. The chondrite-normalized rare earth element patterns (LaN/LuN=1.47-5.12) show low to medium enrichment, which reveal that the rocks were obtained from similar sources in Murgul volcanic rocks. The initial 87Sr/86Sr values range from 0.70442 to 0.70525, and the initial 143Nd/144Nd values range from 0.512741 to 0.512770. The main solidification processes involved in the evolution of the volcanic rocks consist of fractional crystallization with minor amounts of crustal contamination and magma mixing. All geochemical data support that these rocks originated from andesitic magma, and that the parental magma of the rocks were probably derived from an enriched upper mantle, previously modified by subduction-induced metasomatism in a geodynamic setting.
- MakaleYalnız künye2014Geochemistry of dacitic volcanics in the Eastern Pontides (NE Turkey)
Sipahi, Ferkan; Sadıklar, M.Burhan
Dacitic rocks that crop out around the Zigana Mountain (Gümüşhane) in the eastern Pontide (NE Turkey), are mainly composed of quartz, plagioclase, sanidine, amphibole, muscovite, and biotite as the main minerals. Zircon and rutile are the accessory minerals. Pyrite, chalcopyrite, and covellite are the opaque components. On the basis of trace-element data, dacites have been classified as Dacite-I and Dacite-II. Dacite-I is tholeitic-transitional, whereas Dacite-II is transitional-calc-alkaline. The geochemical variation can be explained by the fractionation of the common mineral phases, such as plagioclase, hornblende, magnetite, and apatite. Dacites also show island-arc properties, with negative Nb, Sr, P, and Ti anomalies. The trace-element distrubitions of the dacitic rocks reflect the typical characteristics of rocks from the subduction-related tectonic setting, with enrichment of large-ion lithofile elements and light rare-earth element, but depletion in high-field-strength elements. The dacitic rocks are developed through plagioclase ± hornblende-controlled fractionation from the same parental magma that settled in two successive stages and are derived from an enriched source, probably by the mixing of slab-derived and lithospheric melts.
- Proje2013Doğu pontid kuzey zonunda yüzeylenen paleozoyik yaşlı granitlerin U-Pb zirkon yaşlandırması, Sr-Nd-Pb-O izotop sistematikleri ve jeodinamik evrimi
Kaygusuz, Abdullah; Arslan, Mehmet; Sipahi, Ferkan
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- MakaleAçık Erişim2013Petrogenesis of the late Cretaceous Turnagöl intrusion in the eastern Pontides: Implications for magma genesis in the arc setting
Kaygusuz, Abdullah; Sipahi, Ferkan; Ilbeyli, Nurdane; Arslan, Mehmet; Chen, Bin; Aydinçakir, Emre
A series of Cretaceous plutons is present in the eastern Pontides of northeastern Turkey. The Turnagöl intrusion is the least studied and, thus, the least understood plutons in the orogen. This intrusion consists of hornblende-biotite granodiorites emplaced at 78 Ma based on LA-ICP-MS U-Pb zircon dating. It is of sub-alkaline affinity, belongs to the medium- to high-K calc-alkaline series, and displays features typical of I-type granites. The rocks of the intrusion are enriched in large-ion lithophile elements and light rare earth-elements with negative Eu anomalies (Eu/Eu* = 0.69-0.82), but are deficient in high-field-strength elements. They have a small range of ( 87Sr/86Sr)i (0.7060-0.7063), ÉNdi(-2.6 to -3.1), and δ18O (+8.1 to +9.1) values. Their Pb isotopic ratios are 206Pb/204Pb = 18.63-18.65, 207Pb/ 204Pb = 15.62-15.63, and 208Pb/204Pb = 38.53-38.55. The fractionation of plagioclase, hornblende, and Fe-Ti oxides had key functions in the evolution of the Turnagöl intrusion. The crystallization temperatures of the melts ranged from 758 to 885 C as determined by zircon and apatite saturation thermometry. All these characteristics, combined with the low values of K2O/Na2O and (Na 2O + K2O)/(FeOt + MgO + TiO2), as well as the high values of (CaO + FeOt + MgO + TiO2), suggest an origin by dehydration melting from a metabasaltic lower crustal source.
- Proje2012Doğu pontid kuzey zonu ve kuzey-güney zon geçişinde yüzeylenen kretase-paleosen yaşlı granitoyidik sokulumların petrokimyası, Sr-Nd-Pb-O izotop jeokimyası, jeokronolojisi ve jeodinamik gelişimi
İlbeyli, Nurdane; Kaygusuz, Abdullah; Arslan, Mehmet; Sipahi, Ferkan
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- MakaleYalnız künye2012Trace and rare earth elements as indicators of provenance and depositional environments of Lias cherts in Gumushane, NE Turkey
Eker, Cigdem Saydam; Sipahi, Ferkan; Kaygusuz, Abdullah
Trace elements and rare earth elements (REEs) of Lias-aged cherts in the Gumushane area were studied in order to understand their origin and depositional environment. Twenty three chert samples from five stratigraphic sections were analysed by inductively coupled plasma-mass spectrometry, X-ray diffraction, and mineralogical investigation. Lias cherts in the study area are microcrystalline, cryptocrystalline quartz, and megaquartz depending on mineralogical content. Trace elements of the cherts were compared with PAAS, Co, Y, and Th had stronger depletions in the five sections, whereas V, Ni, Zr, Nb, and Hf had smaller depletions. The distribution of Zr, Hf, and Ta yields Zr/Hf, Zr/Ta and Hf/Ta ratios (25/645, 37/665, and 0.18/3, respectively) that differ from those of chondrites and average upper continental crust, suggesting that these elements are likely non-detrital but are sourced from seawater. Th/U ratios range from 0.04 to 0.45 and are lower than those of the upper continental crust (average: 3.9). Lias-aged cherts have low total REE abundances and stronger depletions in five sections of the PAAS and chondrite-normalised plots. The cherts are characterised by a positive Eu anomaly (average: 4.9) and LREE-enrichment (LaN/YbN=average: 3.5). In addition, about one-half of the cherts exhibit positive Ce anomaly (range: 0.25-2.58), chondritic Y/Ho values (range: 3.3-60), and low (La/Ce)N values (average: 1.8). REE and trace element abundance in Lias cherts indicate that these elements were likely derived from hydrothermal solutions, terrigenous sources, and seawater. The REE patterns of the cherts show that they were probably deposited close to a continental margin.
- MakaleYalnız künye2012Geochronological evidence and tectonic significance of Carboniferous magmatism in the southwest Trabzon area, eastern Pontides, Turkey
Kaygusuz, Abdullah; Arslan, Mehmet; Siebel, Wolfgang; Sipahi, Ferkan; Ilbeyli, Nurdane
The northern and southern zones of the eastern Pontides (northeast Turkey) contain numerous plutons of varying ages and compositions. Geochemical and isotopic results on two Hercynian granitoid bodies located in the northern zone of the eastern Pontides allow a proper reconstruction of their origin for the first time. The intrusive rocks comprise four distinct bodies, two of which we investigated in detail. Based on LA-ICP-MS U-Pb zircon dating, the Derinoba and Kayadibi granites have similar 206Pb/ 238U versus 207Pb/ 235U Concordia ages of 311.1 2.0 and 317.2 3.5 million years for the former and 303.8 1.5 million years for the latter. Aluminium saturation index values of both granites are between 0.95 and 1.35, indicating dominant peraluminous melt compositions. Both intrusions have high SiO 2 (74-77 wt.%) contents and show high-K calc-alkaline and I-to S-type characteristics. Primitive mantle-normalized element diagrams display enrichment in K, Rb, Th, and U, and depletion in Ba, Nb, Ta, Sr, P, and Ti. Chondrite-normalized rare earth element patterns are characterized by concave-upward shapes and pronounced negative Eu anomalies with L acn/Y bcn=4.6-9.7 and E ucn/Eu*=0.11-0.59 (Derinoba), and L acn/Y bcn=2.7-5.5 and E ucn/Eu*=0.31-0.37 (Kayadibi). These features imply crystal-melt fractionation of plagioclase and K-feldspar without significant involvement of garnet. The Derinoba samples have initial Nd values between-6.1 and-7.1 with Nd model ages and T DM between 1.56 and 2.15 thousand million years. The Kayadibi samples show higher initial Nd (I) values,-4.5 to-6.2, with Nd model ages between 1.50 and 1.72 thousand million years. This study demonstrates that the Sr isotope ratios generally display negative correlation with Nd isotopes; Sr isotope ratios were lowered in some samples by hydrothermal interaction or alteration. Isotopic and petrological data suggest that both granites were produced by the partial melting of early Palaeozoic lower crustal rocks, with minor contribution from the mantle. Collectively, these rocks represent a late stage of Hercynian magmatism in the eastern Pontides.
- MakaleYalnız künye2011Formation of skarns at Gumushane (Northeastern Turkey)
Sipahi, Ferkan
Skarn deposits are located in the NE Black Sea region of Turkey belonging to the Alpin metallogenic province. The Fe skarn deposit at Arnastal is hosted by Late Cretaceous carbonate rocks comprised of limestone and the skarn occurrence at Camibogazi dolomitic limestone, adjacent to the Eocene Zigana Granitoid. The prograde textures include rhythmic banding, spots, and mossiness, and the retrograde textures are shock-induced and brecciated. These are identified in the Fe skarn deposit at Arnastal, where there are mineral parageneses of andradite, actinolite, tremolite, epidote, quartz, magnetite, and hematite, and less pyrrboune and pyrite. Additionally, well-crystallized vesuvianite, well-crystallized phlogopite, and diopside in the skarn occurrence. at Camibogazi are identified. Some of the skarn minerals are calcic and have high Mg/(Mg + Fe) ratios. Clinopyroxene consists of diopside (Di(96.66-99.04)Hd(0.67-2.80)Jo(0.29-0.55)). Vesuvianite is mostly Mg-rich, and has a very low MnO content (<0.1 %). Other skarn minerals are Fe-rich. Garnet is characterized by oscillatory zoning and has an andradite composition (Ad(72)Gr(28) to Ad(98)Gr(2)). Epidote has an Fe content of 8.96 to 12.42 wt%. Magnetite is generally massive and sporadically banded with some martitization. The formation temperatures of skarn minerals range from 330 to 600 degrees C. In addition, mass change calculations from the granitoid and andesite toward the skarn zone indicate that there is considerable mass transfer of Si, Al, Fe, and Mg to the carbonate rocks during skarn formation. The average mass changes are estimated at a depletion of 41 g/100 g in granitoid and a gain of 8 g/100 g in andesite. Fe skarn deposit and skarn occurrence are characterized by early, high-temperature mineral assemblages dominated by the anhydrous minerals garnet and diopside and late low-temperature assemblages with hydrous minerals, such as vesuvianite, phlogopite, and epidote. The type of garnet and the abundance of magnetite with minor pyrite suggest that the Fe skarn deposit at Arnastal forms under relatively oxidized conditions. The type of clinopyroxene in the skarn occurrence at the Camibogazi shows oxidized skarns.