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This is the first report on sepiolite occurrences from ultramafics of Nain ophiolitic sequence. Sepiolite is a hydrous clay mineral with fibrous structure that is very important for industrial applications due to properties. Formation of sepiolite is related to several reactions in ultramafics of Nain ophiolite. This process is carried out in three main stages. At first, the hydrothermal fluids have been affected on ultramafic rocks so they altered to serpentinite. The influx of CO₂-H₂O bearing fluids along shear zones in serpentinized and brecciated ultrabasics caused dissolution and carbonatization of serpentinites. During the carbonation of serpentinite, reaction between ultrabasics with hydrothermal fluids have led to formation of Mg and/or SiO₂ bearing solutions at low temperatures, and finally, sepiolite resulted from interaction of  CO₂, H₂O rich hydrothermal fluids.

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In the southeast of Nir, south of Yazd Povince, several acidic volcanoes  rocks are exposed and form the youngest volcanic rocks in this region with dacite-rhyodacite composition. These rocks are composed of plagioclase, hornblende, biotite and quartz phenocrysts with trachytic and hyallomicrolithic porphyry texture. Based on geochemical data, the magmatic affinity of these rocks is calc-alkaline with enrichment of LILE and depletion of HFSE. These characteristics with steep decrease pattern of rare earth elements and negative anomaly of HFSE, such as Nb, Ti and P, indicate the formation of magma in active continental margin. Higher levels of SiO₂, Sr, Sr/Y, and La/Yb with low levels of MgO, Yb, and Y, indicate high silica adakite affinity. It seems that the formation of parental magma of these rocks is consequence of the melting of garnet amphibolite or eclogite rocks of subducted metamorphosed Neotethys oceanic lithosphere in the Central Iran- Arabian plate collision zone during the Neogene time.

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The present study focuses on the geochemistry and genesis of REE minerals in the Tang-e Pirzal karst bauxite deposit. The deposit is located about 45 km east of Dehdasht city in the central part of the Zagros Fold Belt. The ore bodies comprise a series of contiguous lenses that occur as infills of deep karst cavities, depressions, and fractures within the upper neritic carbonates of the Cenomanian–Turonian Sarvak Formation and are structurally controlled by strike-slip fault systems. The most frequent authigenic REE minerals are fluorocarbonates of bastnäsite group that form a solid solution series between end members parisite (CaCe₂(CO₃)₃F₂) and bastnasite (CeCO₃F). The formation of bastnasite-Ce and parisite-Ce suggests that cerium as fluoride and/or carbonate–fluoride complexes were simply leached by acidic downward solutions and finally precipitated on the geochemical barrier of the carbonate bedrock under alkaline and reducing conditions. Cerianite (CeO₂) occurs mainly as fine grains in the porous aggregates of the cryptocrystalline matrix. Cerianite precipitation may occur due to the predominance of acidic/oxide conditions in the upper parts of the bauxite profile. Examination of the vertical distribution of the ∑REE, (La/Yb)_N, Ce/Ce*, and Eu/Eu* indexes indicates progressive enrichment of the REE and slight LREE/HREE fractionation toward the lower parts of the bauxite profile. Cerium behaves differently from the other REEs and shows fluctuating behavior throughout the Tang-e Pirzal profile, which can be related to periodical fluctuations of the groundwater table in response to environmental changes.