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- 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.
AtıfScopus28WoS26OpenAlex25
İncele - MakaleYalnız künye2011Scopus SJRQ2Calc-alkaline I-type plutons in the eastern Pontides, NE Turkey: U-Pb zircon ages, geochemical and Sr-Nd isotopic compositions
Kaygusuz, Abdullah; Şen, Cüneyt
The Köprübaşi{dotless} intrusion from the eastern Pontides of NE Turkey consists of granodiorite and monzogranite, and contains a number of mafic microgranular enclaves (MMEs). We report here U-Pb zircon age, geochemical and Sr-Nd isotopic data for these rocks in order to determining magma sources and magma production processes. On the basis of U-Pb zircon sensitive high-resolution ion microprobe dating (SHRIMP), the magma emplacement age of the granodiorite is 79.3±1.4Ma. The rocks of the pluton are calc-alkaline, metaluminous to peraluminous characteristics, and display features of I-type granites. They are enriched in large ion lithophile elements (LILE) and light rare earth elements (LREE) with negative Eu anomalies (Eu/Eu*=0.60-0.76), but are depleted in high field strength elements (HFSE). They have small range of 87Sr/86Sr(i) (0.7067-0.7070) and e{open}Nd(i) (-3.2 to -4.4) values. Fractionation of plagioclase, hornblende and Fe-Ti oxides played an important role in the evolution of the Köprübaşi{dotless} intrusion. A relatively shallow intrusion depth (∼2-8km) was estimated from the Al-in-hornblende geobarometry. All these characteristics, combined with the low values of K2O/Na2O, SiO2, Al2O3/(FeOT+MgO+TiO2) and (Na2O+K2O)/(FeOT+MgO+TiO2), suggest an origin by dehydration melting from a metabasaltic lower crustal source.
AtıfScopus39WoS36OpenAlex45İncele