Economic Geology
SHAHRAM RAHMANI; Hasan Zamanian; reza Zarei Sahamieh
Abstract
Abstract: The study area is located 45Km NE Zanjan in the Azerbaijan-Western Alborz zone. Quartz-monzonite and dacitic brecciated tuffs are the main host rocks to the Lubin-Zardeh deposit. These rocks are predominantly of K-high calc-alkaline shoshonitic I-type, metaluminous magnesian affinities of Cordilleran ...
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Abstract: The study area is located 45Km NE Zanjan in the Azerbaijan-Western Alborz zone. Quartz-monzonite and dacitic brecciated tuffs are the main host rocks to the Lubin-Zardeh deposit. These rocks are predominantly of K-high calc-alkaline shoshonitic I-type, metaluminous magnesian affinities of Cordilleran type. The intrusive rocks are enriched in LILE, LREE and depleted from HFSE, MREE and HREE and Y. A listric-shaped REE pattern and average La/Yb ratios of host rock indicates higher water content and fO2 in the magma and hornblende fractionation. Their relatively low to moderate ISr values (0.7047–0.7051), positive εNd (t = 36 Ma) values (0.39–2.1) and TDM ages of 0.69 to 1.06 Ga, with Pb isotopic ratios of (206Pb/204Pb) i = 18.49–18.68, (207Pb/204Pb) i = 15.58–15.61 and (208Pb/204Pb) i = 38.33–38.77. Based on textural evidence (coarse amphibole crystals), geochemical data (major, trace and Rare earth elements) and isotopic contents of Pb, Sr-Nd, it is suggested that these rocks correspond to geochemical and isotopic compositions of the host rocks of porphyry and epithermal deposits in the Urmia Dokhtar zone of West Alborz-Azerbaijan (Arasbaran) and Eastern Pontides epithermal deposits, Turkey.
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.
