Mineral Chemistry and Geochemistry of Volcanic Rocks in The North
of Pasinler (Erzurum)
Journal Name:
- Pamukkale Üniversitesi Mühendislik Bilimleri Dergisi
Keywords (Original Language):
Abstract (2. Language):
In the north of Pasinler (Erzurum), Upper Miocene-Pliocene volcanic rocks crop out. These volcanites are composed of basaltic andesite, andesite, dacite, rhyolite lavas and rhyolitic pyroclastics. The rocks show porphyritic, microlitic porphyritic, hyalo-microlitic porphyritic, vitrophyric, glomeroporphyritic, pilotaxitic and hyalopilitic textures. The investigated volcanites contain plagioclase (An29-80), olivine (Fo65-82), clinopyroxene (augite), orthopyroxene (enstatite), amphibole (Mg#: 0.57-0.71), biotite (phlo-gopite: 0.44-0.47, annite: 0.33-0.37), sanidine, quartz and opaque mineral (titano-magnetite and il-menite). The volcanic rocks are calc-alkaline in character and have medium to high-K contents. Ma¬jor oxide and trace element variations point out open-system magmatic differentiation in the evolution of rocks. Geochemical data indicate an important role of fractionation of phenocryst phases in the rocks during differentiation process. However, it is considered that assimilation±magma mixing might have accompanied to the process. High LILE (K, Rb, Ba, Th) and relatively low HFSE (Nb, Ta, Hf, Zr) contents of the rocks indicate that these rocks derived from parental magmas carrying subduc-tion signature.
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Abstract (Original Language):
Pasinler (Erzurum) kuzeyinde Ust Miyosen-Pliyosen ya§li volkanik kayaglar yuzeylemektedir. Bu vol-kanitler bazaltik andezit, andezit, dasit, riyolit turu lav ve riyolitik piroklastiklerden olu§maktadir. Ka-yaglarda porfirik, mikrolitik porfirik, hyalo-mikrolitik porfirik, vitrofirik, glomeroporfirik, pilotaksitik ve hyalopilitik dokular gozlenmektedir. Kayaglar plajiyoklas (An29-80), olivin (Fo65-82), klinopiroksen (ojit), ortopiroksen (enstatit), amfibol (Mg#: 0.57-0.71), biyotit (filogopit: 0.44-0.47, annit: 0.33-0.37), sani-din, kuvars ve opak mineral (titanomanyetit ve ilmenit) igermektedir. Kayaglar kalkalkali karakterli olup, orta-yuksek potasyum igerigine sahiptirler. Ana oksit ve iz element degi§imleri kayaglarin geli-§imindeki agik sistem magmatik diferensiyasyona i§aret etmektedir. Jeokimyasal veriler kayaglarda-ki fenokristal fazlarin fraksiyonla§masinin diferansiyasyon surecinde etkili oldugunu gostermekte-dir. Fakat buna asimilasyon±magma kari§iminin da e§lik etmi§ olabilecegi du§unulmektedir. Kayaglarin yuksek buyuk iyon yarigapli element (K, Rb, Ba, Th) ve goreceli olarak du§uk yuksek alan enerji-li element (Nb, Ta, Hf, Zr) igerikleri kayaglarin yitim izleri ta§iyan bir ana magmadan olu§tuklarina i§a-ret etmektedir.
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