J Ghalamghash; R Chaharlang
Abstract
The Late Miocene- Quaternary volcanoes including Sahand, Ararat, Nemrut, Suphan, Tendurek and Lesser Caucasus volcanoes in the Arabia-Eurasia collision zone, are studied in this paper. The volcanoes have been erupted pyroclastic materials and lava flows with basaltic to rhyolitic composition, in several ...
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The Late Miocene- Quaternary volcanoes including Sahand, Ararat, Nemrut, Suphan, Tendurek and Lesser Caucasus volcanoes in the Arabia-Eurasia collision zone, are studied in this paper. The volcanoes have been erupted pyroclastic materials and lava flows with basaltic to rhyolitic composition, in several times. These volcanic rocks have calk-Alkaline (Sahand) to Alkaline nature (Tendurek). The Nb, Ta, Ti and Y depletions in accompanied with Rb, Ba, K, Sr and Th enrichments are the common geochemical features of these volcanic rocks in primitive mantle normalized multi element diagrams. In addition, enrichment of LREE relative to HREE in chondrite–normalized REE patterns is visible in all volcanic rocks of the regions. The enrichment of LREE and depletion of HREE in Sahand and Lesser Caucasus volcanic rocks is implying that their magma is derived from fraction melting of garnet-lherzolite of mantle source. In contrast, the volcanoes of eastern Anatolia melted from spinel-lherzolite rocks of mantle. The negative Nb, Ta anomalies in primitive mantle normalized multi element diagrams of volcanic rocks indicate geochemical features of Pre-collision subduction component in parental magma of studied volcanoes. High contents of La, Th, Ce and Rb indicate magma contamination during parental magma emplacement in crust accompanied with assimilation, fractional crystallization process.
mohammad parchekani; M Shahrabi; K Bazargani-Guilani
Abstract
The west Alborz area with a crustal thickness of 35-40 Km is a part of the Alborz ranges and is located in the western part of the Alpine-Himalaya belt. This area is folded by Alpine orogeny and the orogen is formed by collision between Iranian and Arabian blocks. A thick and widespread sequence of volcanic ...
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The west Alborz area with a crustal thickness of 35-40 Km is a part of the Alborz ranges and is located in the western part of the Alpine-Himalaya belt. This area is folded by Alpine orogeny and the orogen is formed by collision between Iranian and Arabian blocks. A thick and widespread sequence of volcanic and pyroclastic rocks with 3800m thickness, Eocene in age, outcropped in west Alborz (Karaj Formation, KF). These rocks are intruded by younger plutons with Tertiary age. There are numerous geological, petrological, stratigraphical, geochemical and tectonical similarities between Miocene volcanic rocks in Turkey and study area in Iran (Eocene). The only difference is in age of volcanism in Turkey and Iran.
