Sürdürülebilir Kalkınma Amaçları
Yayınlar
- MakaleYalnız künye2026Organic Geochemical Properties of the Miocene Coal Seam in the Ömerler Field, Tunçbilek Basin, Western Türkiye: Implications for Depositional Environment
Saydam Eker, Çiğdem; Köse, Yeliz
In this comprehensive study, which was conducted based on data obtained from the Ömerler Field İğdekuzu underground mine located in the Tunçbilek Basin (Kütahya/W. Turkey), the aim was to reveal the organic matter content, origin, thermal maturation level, depositional environment, and conditions of Miocene-aged coals. Coal samples collected from the underground coal mine were subjected to proximate analysis, Rock-Eval pyrolysis/Total organic carbon (TOC), gas chromatography (GC), gas chromatography–mass spectrometry analysis (GC–MS) of aromatic and saturated biomarkers and extraction analysis. On an air-dry basis, the average moisture (Mad), volatile matter (Vad), ash (Aad), fixed carbon (FCad) and total sulphur contents of coals are 2.79%, 33.93%, 18.71%, 44.31% and 1.40%, respectively. TOC content is so high; the highest mean TOC content is 86.75% calculated in the upper coal seam, followed by the middle seam with 85.14% and the lower seam with 79.01%. In the GC–MS of the coal samples, the n-alkane distribution varies between C12 and C36. The lowest homohopane index (HHI) value was calculated as 0.02 for OR-5, and the highest HHI value was 0.05 for TB-8. The upper coal seam sample exhibits the order of C29>C28>C27 sterane (%), and the lower and middle coal seam samples exhibit the order of C29>C27>C28 sterane (%). The coal samples under study exhibit early mature oil window behaviour according to all geochemical maturity parameters. These coals indicate a mixed organic matter of Type II/III and III kerogens, as demonstrated by medium and long-chain n-alkanes, terrestrial/aquatic organic matter ratios (TAR), aquatic plants to terrestrial plants ratios (Paq), C24 Tet/C26 Tri and C19/C23 Tri ratios, and distributions of C27–29 ααα20R, likely deposited in a paralic, oxic-dyoxic transitional environment. Although the TOC value of the Miocene-aged coal samples is so high, they have not yet reached the level of producing hydrocarbons due to low and medium hydrogen index (HI), low quality index (QI), production index (PI), and bitumen index (BI) values, but it has been evaluated that they have the potential to produce gas.
- MakaleAçık Erişim2025Zircon U-Pb geochronology and Sr-Nd-Pb-Hf-O isotope signatures of Middle Eocene high-K plutons from the Eastern Pontides Orogenic Belt, NE Turkey: implications for parental magma sources and magmatic processes
Kaygusuz, Abdullah; Güloğlu, Zikrullah Samet; Aydınçakır, Emre; Yücel, Cem; Vural, Alaaddin; Saydam Eker, Çiğdem; Cicerali, Derya
The Eastern Pontides Orogenic Belt (EPOB) in northeastern Turkey is a well-preserved continental magmatic arc in the Alpine-Himalayan Orogenic Belt and contains many Eocene I-type high-K plutons. Employing LA-ICP-MS U-Pb zircon geochronology, the crystallization ages of the investigated Yaylalıköy and Taşbaşı plutons were established to be Lutetian (Middle Eocene), ranging from 47 Ma to 46 Ma. These plutons exhibit a compositional spectrum ranging from diorite to granodiorite, characterized by I-type, metaluminous, and high-K geochemical signatures. Notably, they are enriched in large-ion lithophile elements (LILEs) and light rare earth elements (LREEs), displaying pronounced negative Eu anomalies (EuN/Eu* = 0.58–0.96). Isotopic signatures reveal homogeneous and moderately low initial 87 Sr/86 Sr(i) ratios (0.704643–0.705034) and positive εNd(i) values (0.24 to 1.67) for the investigated plutons. These isotopic signatures are consistent with mantle origin, as evidenced by their position within the mantle array on isotope ratio diagrams. Lead isotope compositions exhibit limited variations, with initial ratios of 206 Pb/204 Pb(i) (18.55–18.64), 207 Pb/204 Pb(i) (15.61–15.64), and 208 Pb/204 Pb(i) (38.46–38.75). Zircon εHf(i) values are positive (2.32–6.20), plotting between the depleted mantle and chondritic evolution lines. Additionally, these rocks display low zircon δ18 O values (+4.54 to + 6.53‰), comparable to mantle composition. The petrographic characteristics of the investigated plutons suggest that fractional crystallization with minimal assimilation and/or magma mixing played a dominant role during their solidification. The integration of geochemical and isotopic data, alongside regional geological constraints, advocates for enriched lithospheric mantle as the source for the parental magmas of the studied plutons. These magmas subsequently underwent differentiation within a deep-seated magma chamber, followed by emplacement into the crust.
- MakaleAçık Erişim2025Geochemical evaluation of black limestones in the Early Cretaceous platform carbonates of Gümüşhane (NE Turkey): An insight into petroleum source rock potential and palaeoenvironment conditions
Saydam Eker, Çiğdem; Arı, Uğur Volkan; Alemdağ, Selçuk
This study assesses the organic matter (OM) content, kerogen type, maturity, depositional environment conditions and sedimentation model of Early Cretaceous (Berriasian–Aptian) black limestones in NE Turkey using geochemical analyses, including Rock-Eval/total organic carbon (TOC), gas chromatography–mass spectrometry, gas chromatography, major and trace elements and stable carbon isotope of OM measurements. The investigated black limestones' TOC, hydrogen index and potential yield values range from 0.07 to 2.91 wt%, 76 to 636 mg HC/g TOC and 0.15 to 11.17 mg HC/g rock, respectively. These results indicate that the examined limestones have variable source rock potential, ranging from low to high. Tmax values, calculated saturated biomarkers and aromatic components suggest that the OM contained in the black limestones varies between thermally immature and mature, consistent with the potential index values. The OM found in the black limestone contained kerogen varying between type I and III. It is a composition of marine and terrigenous OM, as shown by the δ13C isotope values, biomarker components and n-alkane distributions and their parameters. This OM was deposited in a salinity water environment with marine–terrigenous (transitional) surroundings under oxic, suboxic to anoxic and arid–hot climate conditions. These findings provide critical insights for assessing the hydrocarbon potential of carbonate platforms in similar geological settings.
- MakaleYalnız künye2025First evaluation and ecological risk of potentially toxic elements in the formations of Akçakale cave (Gümüşhane-NE-Türkiye)
Saydam Eker, Çiğdem; Külekçi, Gökhan; Uçak, Gül
In this study, the potential toxic element levels (PTEs) and adverse health effects of Akçakale cave formations were evaluated using geochemical parameters such as enrichment factor (EF), geo-accumulation index (Igeo), contamination factor (CF), ecological risk factor (Eri), potential ecological risk index (PERI), and non-carcinogenic hazard index (HI). Water does not pose a pollution risk, as the concentrations of potentially toxic elements in all samples are within the permissible limits for drinking water. According to the calculated geochemical parameters, all the samples were polluted with As, Co, Ni, Cu, V, and Pb. Ni, As, Cu, and Pb show very high ecological risk (PER > 320) in all samples, except Cu and Pb in T2T. The PERI values of the PTEs were more than 600 in all samples, indicating a very high potential ecological risk. The HI > 1 values for Co and As in all samples for both adults and children suggested potential non-carcinogenic health risks from exposure to these elements in the cave environment. The PTEs in the Akçakale cave formation were most likely linked to lithogenic, geogenic (Pb–Zn-Cu mineralization), and anthropogenic (agricultural activities) processes, per the findings of the data analysis using multivariate statistics (PCA and PCC). These data obtained are the first findings regarding the potential toxic element content of Akçakale cave.
- MakaleYalnız künye2025Concentrations, distribution, and source appointment of heavy metal/loids in non-clastic sedimentary rocks: a case study of early jurassic chert, northeastern türkiye
Saydam Eker, Çiğdem; Kaygusuz, Abdullah; Arı, Uğur Volkan
The Current study used geochemical indicators such as the geo-accumulation index (Igeo), the Enrichment Factor (EF), and the contamination factor (CF) to evaluate the regional distributions and accumulations of various heavy metal/loids (HM; Co, Mo, Pb, Zn, Cu, Ni, As, Cd) in early Jurassic cherts in the Gümüşhane (NE Türkiye). Five stratigraphic section measurement (MS) areas (Tedaş, Alemdar, Akçakale, Tekke, and Pirahmet) and one borehole (Eskibağlar well) were selected for sampling. Major and trace element compositions of the selected 25 samples were measured by inductively coupled plasma optical emission spectrometry (ICP-OES) and inductively coupled plasma mass spectrometry (ICP-MS). Calculated geochemical indexes indicated that Alemdar, Tekke MS, and Eskibağlar well samples were polluted with Pb, Zn, Cu, As, and Cd, Tedaş, Akçakale, and Pirahmet MS samples were polluted with Cd. Pearson's correlation coefficient (PCC) and principal component analysis (PCA) suggested that Zn, Pb, and Cu contaminating the Alemdar, Tekke MS, and Eskibağlar well samples were of ore mineralization origin, As was of terrigenous input, and Cd was probably of diatom origin. PCC and PCA showed that the Cd contaminating the Tedaş, Akçakale, and Pirahmet MS samples was probably of diatom origin, and the other metals found at normal levels in the samples were due to terrigenous input. The Early Jurassic period, which was a rift environment in the Gümüşhane region, is thought to have produced the cherts of the Alemdar, Tekke MS, and Eskibağlar well samples in a graben environment, while the cherts of the Tedaş, Akçakale, and Pirahmet MS were deposited in a horst environment. δU values, Ni/Co, and Vi/(V + Ni) ratios indicated that oxic-anoxic conditions were generally prevalent in the depositional environment, but redox conditions did not affect the abundance and distribution of HMs. These findings provide critical information for assessing heavy metal/loid enrichment and contamination potential not only in clastic sedimentary rocks, river sediments, and soils but also in non-clastic sedimentary rocks.
- MakaleYalnız künye2025Origin 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.
- MakaleYalnız künye2022Eocene magmatism and associated Fe-Cu mineralization in northeastern Turkey: a case study of the Karadağ skarn
Sipahi, Ferkan; Saydam Eker, Çiğdem; Akpınar, İbrahim; Gücer, Mehmet Ali; Vural, Alaaddin; Kaygusuz, Abdullah; Aydurmuş, Tanju
The metallogenic belt containing numerous skarn mineralized systems starting from Eastern Europe continues through Turkey and Iran. The study area in the Eastern Pontides is within this metallogenic belt. The 44.39 ± 0.53 Ma Karadağ Intrusion sourced skarn mineralization is located along the granitoid-to-limestone contact. The Karadağ Intrusion is an arc-like pluton with medium–high K calc-alkaline and peraluminous–metaluminous affinity. The Karadağ Fe–Cu skarn mineralization (Gümüşhane, Turkey), an exoskarn, is hosted by Late Cretaceous limestone and consists of early garnet, clinopyroxene, and orthoclase with late epidote and chlorite. Primary ore minerals are magnetite and haematite, accompanied by minor amounts of chalcopyrite and pyrite. Pyroxene comprises mostly diopside and less hedenbergitic diopside and johannsenite. Wollastonite is very rare. Garnet is andradite and grossular–andradite. Thus, all these results imply that the Karadağ Fe–Cu skarn mineralization formed under relatively oxidized and Fe-rich conditions. The homogenization temperatures of the fluid inclusions vary from 189°C to 405°C for quartz and 186°C to 430°C for calcite. The salinity contents in the fluid inclusions are within 0.2–9 wt% NaCl equivalent for quartz and 0.4–14.8 wt% NaCl equivalent for calcite. First melting temperatures between −36.5 and −47.4°C were attained with the presence of NaCl–FeCl2± CaCl2 in the initial phase of fluid inclusions. The first melting in the later stage of fluid inclusions is between −3.8 and −17.2°C, thereby, supporting the existence of NaHCO3-Na2CO3-KCl-type salt composition. The δ18O values of minerals are 1.7–10.3‰ for garnet, 11.1–14.6‰ for quartz, 6.4 to 6.8‰ for epidote, and 2.8–3.8‰ for magnetite in the Karadağ skarn mineralization. The δ18O value of epidote indicates magmatic fluid, whereas those of garnet, magnetite, and quartz suggest magmatic fluids together with less meteoric effect. The δ18O values in limestone (18.7 to 22.3‰), marble (8.7‰), and calcite (10.5 to 12.2‰) were depleted relative to typical δ18O contents of marine carbonates (20 to 30‰). Moreover, the C isotope values of calcite (−5.4 to −1.4‰), marble (−2.1‰), and limestone (1.0 to 1.2‰) reflect those of metamorphic rocks and skarns (−4.0 to 3‰ and −18 to 2‰). Mineral paragenesis, fluid inclusion, and stable isotopic signatures are consistent with ore mineralization caused by the interaction of magmatic fluids with carbonate host rocks. Karadağ Fe-Cu skarn mineralization, associated with Karadağ postcollisional magmatism, is an example of skarn mineralized system in the Eastern Pontides.
- MakaleAçık Erişim2021Geochemistry and Pb isotopic proof for sources of heavy metal(loid)s in Late Cretaceous sandstones from Eastern Pontides (NE Turkey)
Saydam Eker, Çiğdem
Upper Cretaceous sedimentary rocks are widely exposed around Trabzon, Giresun and Gümüşhane in the eastern Pontides. The sedimentary rocks are mainly composed of sandstones and marls, and the thicknesses of these rocks range from 170 to 400 m. This paper focused on Late Cretaceous sandstones of Trabzon, Giresun and Gümüşhane regions to identify the concentrations, sources, deposition environment and conditions of certain heavy metal(loid)s (Zn, Pb, Cu, Ni, As, Co, Mo and V). Enrichment factor (EF), geo-accumulation index (Igeo), Pollution index (Pi), Pollution load index (Pln), Pb isotope and multivariate statistical analysis were performed to elucidate the pollution levels and sources. In general, the evaluation indices exhibited that the sandstones were moderately polluted by As in the Trabzon area, and strongly polluted by Ni and As, moderately polluted by Co and V in the Giresun and Gümüşhane areas. The results of multivariate statistical analyses indicated that As and partly Pb might be originated from anthropogenic sources, whereas other metals were derived from geogenic origin. Lead isotopic analysis demonstrated two characterized signatures of the pollution sources in the sandstones, one related to geogenic origin and the other to coal, gasoline and pesticides. The sandstones were deposited in transition—marine environment under oxic—weak oxic conditions and paleoclimatic conditions ranged from arid to moist during Late Cretaceous period.
- MakaleAçık Erişim2020Geochemical differences between bed and terrace sediments of the Harşit Stream (NE Turkey): Implications for mixed source rocks, weathering and mass transfer
Saydam Eker, Çiğdem
There are minor geochemical differences between Harşit Stream bedandterrace sediments, and these can be owing to the impacts of climatic differences and chemical weathering rather than source rock composition. The bedsediments have lower average SiO2, Al2O3, Fe2O3, K2O, TiO2and MnO concentrations than terrace sediments, but higher concentrations of MgO, CaO and Na2O. The rare earth element (REE) distributions, Eu/Eu*, (Gd/Yb)N, La/Th and (La/Yb)N ratios of the bedand terrace sediments indicate that they derived from a mixture of 3% granodiorite + 50% gabbro + 47% felsic tuff and 5 %granodiorite + 37% gabbro + 58% felsic tuff, respectively. The CIA, PIA, WIP values and ICV, Rb/Sr ratios indicate that the bedsediments are lowly weathered and terrace sediments are lowly tomoderately weathered. The distribution of C-values and Sr/Cu ratios indicate an arid to semiarid climatic conditions for the bedsedimentsand an arid to semi-moist climatic conditions for terrace sediments. During weathering of the mixed source rocks, Na indicates the greatest loss for the bedand the terrace sediments, and P shows the lowest loss for both of sediments. The average of Si, Al, Na, K and Mn exhibits more loss in bedsediments than terrace sediments, the Fe, Mg, Ca and P exhibits less loss in bedsediments than terrace sediments.
- MakaleYalnız künye2020Distinct contamination indices for evaluating potentially toxic element levels in stream sediments: a case study of the Harşit Stream (NE Turkey)
Saydam Eker, Çiğdem
This paper revealed that the level of certain potentially toxic elements (PTEs) can be reflected in stream and terrace sediments from Harşit Stream in Northeast Turkey. The potential toxicity of these elements was established by determining and interpreting the enrichment factor (EF), contamination index (Pi), ecological risk index (Eri), modified hazard quotient (mHQ), hazard quotient (HQ), and hazard index (HI). The distribution of PTEs in the sediment samples was non-uniform along the different sites of the stream. The change in concentration was attributed to the release of these elements from different sources (agricultural activities, industrial activities, and gasoline discharges). Results indicated that the stream sediments were locally contaminated by the following PTEs: Pb, As, and Cd based on EF values; Cu, Pb, Zn, As, Cd, and Hg based on Pi; Pb, Cd, and Hg based on Eri; and Pb, As, Cd, and Hg based on mHQ. According to the HQ and HI values of Pb, risks were posed to human health especially to children. Meanwhile, terrace sediments were locally contaminated as follows: Zn and As based on EF; Cu, Pb, Zn, As, and Cd based on Pi; and Zn and Cd based on Eri. The HQ and HI values of As were found to be > 1, suggesting a high chance of health risk to children. The PTE levels and the local distribution pattern revealed that agricultural activities, industrial functions, and gas stations along the stream were probable sources of toxic element contamination in sediments from the Harşit Stream. These findings can help evaluate the potential toxicity risks affecting living organisms.
- MakaleYalnız künye2020Comparison of sandstone and mudstone with different methods for assessing toxic element contamination in the Early–Middle Jurassic sediments of Gümüşhane (NE Turkey)
Saydam Eker, Çiğdem; Arı, Uğur Volkan
To investigate the vertical changes of toxic elements in Jurassic sediments, sampling was performed in four sites. Samples were collected from sandstones and mudstones/marls and analyzed for some toxic elements (Cu, Pb, Zn, As, Ni and V). Results exhibited that the sediment grain size played a significant role in controlling the concentrations of the toxic elements in the sediments. The mean toxic element contents of mudstones/marls were higher than those of sandstones (except Cu). The contamination level of toxic elements was detected by enrichment factor (EF), geo-accumulation index (Igeo), potential ecological risk index (Eir), pollution index (Pi) and united pollution index (PIn). The low EF, Igeo, Eir, Pi and PIn for Cu, Pb, Zn, Ni, V in the sandstones and Cu, Zn, Ni in the mudstones/marls exhibited an absence of clear these elements pollution. The high EF, Eir, Pi and PIn for As (9.7, 73, 7 and 29, respectively, as mean values) in the sandstones and for As (49.3, 222, 22 and 75, respectively, as mean values) Pb (8.8, 24, 5 and 19, respectively, as mean values), V (8.3, 15, 7 and 39, respectively, as mean values) in the mudstones/marls indicated significant contamination. Additionally, according to the potential ecological risk (RI) values, the sandstones had low potential ecological risk for the toxic elements (RI < 150) and the mudstones/marls had moderate potential ecological risk (150 ≤ RI ≤ 300). The potential ecological risk As, Pb, V (especially As) were higher in urban areas than in agricultural activities. Therefore, the source of As, Pb, V could be gasoline combustion, burning coal and vehicle exhausts. The contents of these elements generally increased from bottom to top of the measured stratigraphic sections, which indicated transported by atmospheric conditions.
- MakaleYalnız künye2020Geochemistry of the Middle Jurassic sediments in Gümüşhane, north-eastern Turkey: Implications for weathering and provenance
Saydam Eker, Çiğdem; Arı, Uğur V.
The whole-rock geochemistry and Sr-Nd isotope data of Middle Jurassic sedimentary rocks in the Gümüşhane area (north-eastern Turkey) were analysed to reconstruct the provenance, chemical weathering, sediment recycling history, and tectonic setting of the source area. Based on trace element ratios and rare earth element (REE) patterns, it was interpreted that the sandstones were derived from a source area with felsic-mafic rocks as dominant contributors. The average chemical index of alteration (CIA) and weathering index (WIP) values are low with respect to Upper Continental Crust (UCC) in the studied sandstones and mudstones, but the index of compositional variability (ICV) values are high, thus revealing weak–moderate weathering conditions. The average Th/U ratios of the sandstones and mudstones indicate a relatively simple cycling history. The positive and low negative εNd values support the supposition that the source area did not undergo much sedimentary change. A model mixture composed of 60% granite, 5% granodiorite, and 35% gabbro could be deduced to be the potential source composition of Middle Jurassic sediments; this model was reinforced by the 87Sr/86Sr ratios and εNd(t) values of the sediments. The Middle Jurassic siliciclastic sedimentary rocks of the Gümüşhane region were likely deposited in a tectonic environment with a passive margin.
- MakaleYalnız künye2020Geochemical composition of magnetite from different iron skarn mineralizations in NE Turkey: implication for source of ore-forming fluids
Sipahi, Ferkan; Gücer, Mehmet Ali; Saydam Eker, Çiğdem
Iron oxide mineralizations in the eastern part of the Pontides (NE Turkey) are hosted in the skarn environments which are the Pontide paleomagmatic arc. These mineralizations always occur in the contacts between granitoid and limestone. Magnetites are hosted in carbonate rocks and generally formed during garnet-magnetite-epidote-quartz phase. Magnetites have high Co (15.8–43.4 ppm for the Kopuz, 11–12.5 ppm for the Eğrikar, and 3.8–1266.7 ppm for the Karadağ) concentrations suggesting that the sulfide decreased from the early to the late phases in the iron skarn mineralization forming systems. The Co/Ni ratios in the magnetites (0.12 to 35.38 for Karadağ, 2.19 to 13.53 for the Kopuz, and 2.39 to 5.21 for the Eğrikar) show the hydrothermal effect on the magmatic source in iron skarns in the study area. Thus, variable Co/Ni ratios reflect interactions between the magma with the host rock during successive alteration stages. Magnetites in this study have Sc-Nb-Mg-Ti depletions and Ta enrichment. In this study, high Co, Ti, and V contents in magnetites suggest the high temperature (300–500 °C) and low ƒO2. The V contents of the magnetite in the Karadağ increase with the decreasing oxygen fugacity of fluid(s) forming magnetites, whereas the V contents of the magnetites in the Kopuz and Eğrikar decrease with increasing oxygen fugacity of fluid(s) forming magnetites. Element patterns and Ni/Cr ratio (< 1) of the magnetite are geochemically similar to those of magnetite in Fe-skarn deposits and partly magmatic accessory magnetite of I-type granites. As a result, the Co, Ni, V, and Ti elements of the magnetite have played an important role in the discriminating and interpreting of skarn mineralizations in the eastern Pontides and support a calcic skarn origin with studies of the mineralization geology.
- 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 künye2017Ankara Çayı Dere Yatağı Sedimanlarının Zararlı Element İçeriği
Saydam Eker, Çiğdem; Özkan, Özay
Bu çalışmanın amacı, Ankara Çayı dere yatağı sedimanlarının içermiş olduğu zararlı elementlerin bolluğunu ve kaynağını yorumlamaktır. Ankara Çayı dere yatağı sedimanlarının ortalama Zn, Ni, Cu, Pb, As, Co ve Cd değerleri sırasıyla 111, 65.7, 32, 17.6, 16.4, 16.1 ve 0.2 ppm olarak hesaplanmıştır. İncelenen örneklerin Al/Si oranı ile Cu, Pb, Ni ve Co arasında ve TOK içeriği ile Cu, Pb ve Zn arasında pozitif ilişki gözlenmektedir. Zararlı elementlerin ZF ve Ijeo değerlerine göre söz konusu sedimanlar As ve Ni bakımından önemli, Co, Zn, ve Cu bakımından genel olarak orta, Pb ve Cd bakımından lokal olarak orta derecede kirlenmiştir. Sedimanlardaki ortalama antropojenik (insan kaynaklı) Pb (%) değeri >100% olarak tespit edilmiştir. Dolayısıyla Pb, Cu, Zn, ve Co elementleri genel olarak jeolojik kaynaklı olmakla beraber yer yer antropojenik katkı söz konusudur. Cd çoğunlukla insan kaynaklı olmakla beraber kısmen jeolojik katkı görülmektedir, ancak Ni ve As'nin tamamen insan kaynaklı olduğu düşünülmektedir.
- 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.
- 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.
- 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.