Quaternary Basanitic Rocks within the Eastern Anatolian Volcanism (Turkey): Petrological and Geochemical Constrains
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Dosyalar
Tarih
2017
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
19th EGU General Assembly, EGU2017
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
The Eastern Anatolian Cenozoic continental intraplate volcanism was initiated in Middle Miocene as a result of the
convergence between the Arabian and Anatolian plates. The origin of Eastern Anatolian volcanism has been the
focus of many petrological studies that have aimed to resolve the relative contributions of asthenospheric mantle
and/or lithospheric mantle with/without subduction component in the genesis of magmas that compositionally
have many affinities to ocean island basalts (OIB) and volcanic arcs. Volcanism in the region characterized by
mainly stratovolcanoes, basaltic lava plateaus and are dominantly spread at the northern parts of Bitlis Pötürge
Massif (BPM). Our study focuses on a small scale Quaternary basaltic system that firstly observed within the
BPM. The volcanic rocks of our study located 50 km to the south of Lake Van and are basanitic in composition.
They exposed along K–G striking tensional fissures and crosscut the Upper unit of the Bitlis Massif. Initial
products of the volcanism are scoria fall deposits. Thick basanitic lava flows overly the pyroclastics and formed
columnar structures.
The basanites are generally fine-grained with phenocrysts of olivine+clinopyroxene. The groundmass is typically
of clinopyroxene, olivine and Ti magnetite and Cr spinel with interstitial nepheline. The olivine phenocrysts are
typically euhedral to subhedral with Forsterite contents of Fo73-83. Clinopyroxenes are highly calcic and show
modest variations in Wo47-52-En34-42-Fs10-15 and are weakly zoned with mg# 89-87 at cores to 86-84 at rims.
Nephelines occur as minor minerals within the networks of other groundmass minerals. Ti rich and Fe-Cr spinels
occur as inclusions in olivine and clinopyroxenes as well as within the groundmass.
LILE and LREE enrichments over HFSE and HREE suggest similarities with magmas generated from enriched
mantle sources. EC-AFC modeling of trace element and isotope compositions indicates that assimilation of crustal
lithologies have minor effect on the evolutionary stages of basanitic rocks. Based on LREE/HREE, MREE/HREE
ratios and partial melting models, we suggest that basanitic rocks of Çatak are produced from a lower degree
melting of a garnet bearing mantle source.
Açıklama
Anahtar Kelimeler
Çatak, Basanitic Rocks
Kaynak
19th EGU General Assembly, EGU2017
