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- MakaleYalnız künye2026Scopus SJRQ2Cenozoic Lamprophyres From NE Türkiye: New Constraints on Post-Collisional Metasomatism and Alkaline Magma Origin in the Juvenile Subcontinental Lithospheric Mantle
Arslan, Mehmet; Temizel, İrfan; Krmíček, Lukáš; Yücel, Cem
The Middle Eocene (~43 Ma) and Late Miocene (~6 Ma) lamprophyres cropping out as sills from NE Türkiye can be classified as alkaline lamprophyres. These lamprophyres exhibit moderate contents of K2O (2.22–2.59 and 2.58–2.98 wt%), K2O/Na2O ratios (0.78–1.14 and 0.62–0.94) and Mg# (40.55–46.32 and 56.93–61.52), respectively, and low concentrations of mantle compatible elements. The lamprophyres also have a moderate to relatively high abundance of rare earth elements (ΣREEs = 140–159 and 547–604 ppm, respectively) with significantly fractionated REE patterns (LaN/YbN = 6.82–9.10 and 65.17–71.31, respectively), and are enriched in large-ion lithophile and light REEs but depleted in high-field-strength and heavy REEs. The lamprophyres have homogeneous and moderately low (87Sr/86Sr)i of 0.705048–0.705474 and 0.705252–0.705401, and nearly uniform εNd(i) values varying from −0.47 to 0.20 and 0.54 to 0.79 and εHf(i) values varying from 4.51–6.71 and 5.83–6.18, respectively. They also have a narrow and moderately high Δ7/4Pb range of 6.19–15.41 and 10.62–10.88 and Δ8/4Pb range of 49.56–56.14 and 46.86–47.99, respectively. Petrological modelling suggests that the parental magmas of both the Eocene and Miocene lamprophyres were generated by the low-degree partial melting of phlogopite-bearing spinel-garnet and amphibole-bearing garnet lherzolite sources, respectively. By integrating whole-rock trace elements and isotope compositions with regional geological observations, we propose that the post-collisional Middle Eocene and Late Miocene lamprophyres in the Eastern Pontides Orogenic Belt originated from the juvenile subcontinental lithospheric mantle sources metasomatized initially by Neotethyan subduction-related fluids during the Eocene, and subsequently overprinted by delaminated lithosphere-derived carbonate components in the Miocene. The lamprophyres likely record a temporal magmatic response to lithospheric delamination and regional thermal upwelling associated with Eocene extensional tectonics, followed by lithospheric thinning during the Miocene in a post-collisional tectonic setting.
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İncele - MakaleYalnız künye2014Scopus SJRQ2Geochemical 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.
AtıfScopus28WoS26OpenAlex25İncele - MakaleYalnız künye2008Scopus SJRQ1Petrochemistry and petrology of I-type granitoids in an arc setting: The composite Torul pluton, Eastern Pontides, NE Turkey
Kaygusuz, Abdullah; Siebel, Wolfgang; Şen, Cüneyt; Satir, Muharrem
The Upper Cretaceous Torul pluton, located in the Eastern Pontides, is of sub-alkaline affinity and displays features typical of volcanic arc granitoids. It is a composite pluton consisting of granodiorite, biotite hornblende monzogranite, quartz monzodiorite, quartz monzonite and hornblende biotite monzogranite. The oldest syenogranite (77.9 ± 0.3 Ma) and the youngest quartz diorite form small stocks within the pluton. Samples from the granodiorites, biotite hornblende monzogranites, quartz monzodiorites, quartz monzonites and hornblende biotite monzogranites have SiO2 between 57 and 68 wt% and display high-K calc-alkaline, metaluminous to peraluminous characteristics. Chondrite-normalized REE patterns are fractionated Lacn/Lucn = 6.0-14.2) with pronounced negative Eu anomalies (Eu/Eu* = 0.59-0.84). Initial εNd(i) values vary between -3.1 and -4.1, initial 87Sr/86 Sr values between 0.7058 and 0.7072, and δ18O values between +4.4 and +7.3‰. The quartz diorites are characterized by relatively high Mg-number of 36-38, low contents of Na2O (2.3-2.5 wt%) and SiO2 (52-55 wt%) and medium-K calc-alkaline, metaluminous composition. Chondrite-normalized REE patterns are relatively flat [(La/Yb)cn = 2.8-3.3; (Tb/Yb)cn = 1.2] and show small negative Eu anomalies (Eu/Eu*= 0.74-0.76). Compared to the other rock types, radiogenic isotope signatures of the quartz diorites show higher 87Sr/ 86Sr (0.7075-0.7079) and lower εNd(i) (-4.5 to -5.3). The syenogranites have high SiO2 (70-74 wt%) and display high-K calc-alkaline, peraluminous characteristics. Their REE patterns are characterized by higher Lacn/Lucn (12.9) and Eu/Eu* (0.76-0.77) values compared to the quartz diorites. Isotopic signatures of these rocks [εNd(i) = -4.0 to -3.3; 87Sr/86Sr(i) = 0.7034-0.7060; δ18 O = + 4.9 to + 8.2] are largely similar to the other rock types but differ from that of the quartz diorites. Fractionation of plagioclase, hornblende, pyroxene and Fe'Ti oxides played an important role in the evolution of Torul granitoids. The crystallization temperatures of the melts ranged from 800 to 900°C as determined from zircon and apatite saturation thermometry. All these characteristics, combined with low K2 O/Na2O, low Al2O3/(FeOT + MgO + TiO2), and low (Na2O + K2O)/ (FeOT + MgO + TiO2) ratios suggest an origin through dehydration melting of mafic lower crustal source rocks.
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