Geochemical characteristics of the Arabshah kaolin deposit, Takab geothermal field, NW Iran
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ORIGINAL PAPER
Geochemical characteristics of the Arabshah kaolin deposit, Takab geothermal field, NW Iran Ali Abedini 1 & Ali Asghar Calagari 2
Received: 28 July 2015 / Accepted: 20 June 2016 # Saudi Society for Geosciences 2016
Abstract The Arabshah kaolin deposit (Takab geothermal field, NW Iran) is the product of alteration of Miocene dioritic rocks. According to mineralogical data, the rock-forming minerals in this deposit include kaolinite, quartz, muscovite-illite, pyrophyllite, accompanied by lesser amounts of rutile, chlorite, anatase, albite, gypsum, nontronite, and pyrite. Consideration of elemental ratios and geochemical indices such as TiO2, Nb + Cr, Ti + Fe, Sr + Ba, and La + Ce + Y demonstrated that both hypogene and supergene processes played a significant role in the development of this deposit. The mass change calculations revealed that elements like Zr, Ga, Hf, REEs, and Th which are normally immobile in ordinary alteration processes had both incremental and decremental trends during the development of this deposit. The Eu and Ce anomaly values (normalized to chondrite) in kaolinized samples vary within the range of 0.65–1.13 and 0.91–1.05, respectively. It seems that the variation of negative Eu anomaly values was controlled by kaolinization of feldspars by hypogene solutions and by scavenging of this element by Fe oxides and hydroxides (formed during oxidation of hypogene pyrite by supergene solutions). Variation of Ce anomalies also unravels the effective role of reducing hypogene fluids and to some extent of supergene solutions during kaolinization. Combination of the results obtained from mineralization considerations, mass change calculations of elements, and correlation coefficients illustrate that distribution and concentration
* Ali Abedini [email protected]; [email protected]
1
Geology Department, Faculty of Sciences, Urmia University, Urmia 57153, Iran
2
Department of Earth Sciences, Faculty of Natural Sciences, University of Tabriz, Tabriz 5166616471, Iran
of major, minor, and rare earth elements during kaolinization at Arabshah were affected by the function of factors such as changes in physico-chemical conditions of altering solutions (e.g., Eh and pH), adsorption, accessibility to complexforming ligands, water-rock ratios, existing in resistant (to alteration) mineral phases, and scavenging by Fe and Mn oxides. Keywords Diorite . Kaolinization . Elemental distribution . Arabshah . Takab . Iran
Introduction The Takab district, in general, is one of the eight known metallogenic provinces in Iran. Because of the existence of various metallic (e.g., gold, arsenic, antimony, mercury, iron, lead, zinc, and manganese) and non-metallic (e.g., feldspar, phosphate, talc, salt, borate, coal, dolomite, bauxite, and laterite) mineral deposits, the Takab district has long been the focus of attention for many economic geologists. Among these, the gold (Aghdareh and Zareshooran) and lead-zinc (Angooran) deposits are the most prestigious active mines in this district (Ghorbani 201
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