QE473 : Mineralogy, geochemistry and mineralization of rare earth elements in mextasomatites from the Esfordi region, Northeast of Bafq
Thesis > Central Library of Shahrood University > Geosciences > MSc > 2019
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Abstarct: The study area is located 120 km northeast of Bafq city in Yazd Province. This area is a part of the Posht-e- Badam Block in the Central Iran micro-continent. In the present research, studies were performed on Esfordi, Gazestan, and Lakehsiyah,and Choghart areas. Samples were taken from rocks and ore for petrological, mineralogical, geochemical and fluid inclusion investigations. baxsed on field observations, Rizu series with Late Neoproterozoic – Early Cambrian age is widespread sequences in the Bafq mextallogenic area. The Rizu series represents an alternation of dolomitic rocks, sandstone, tuffaceous sandstone, shale, basaltic lava and tuff, rhyolitic lava and tuff, rhyodacite to andesite, mextasomatites, iron-bearing chert strips (jaspillite), and iron-magnesium oxides. In this area mextasomatites are host rocks of iron-oxide and apatite mineralization, the ore bodies dividing as magnetite-rich, magnetite-apatite-rich, and apatite-rich ores baxsed on the content of magnetite and apatite. Mineralization is observed as banded, massive, vein-veinlets, and rarely stockwork, disseminated, brecciated, open space-filling forms. Mineralogical and texture studies have indicated the presence of four generations of apatite and three generations of magnetite. Petrological studies baxsed whole igneous rock geochemistry proved that those have formed in an intra-continent rift environment. The grades of Fe2O3, P2O5, and ∑REE in ore bodies range from 8.68 – 90.65%, 0.47 – 35.51%, and 357 – 14762 ppm, respectively. The reference samples-normalized rare earth elements (REE) distribution patterns of ores are similar each other, and indicating enrichment of light REE relative to heavy REE and negative Eu anomaly. The average homogenization temperature and salinity of the fluid inclusions in the first-generation apatite were 208℃ and 20.24 wt. % NaCl equivalent, respectively, while the second-generation apatite were 181℃ and 10.36 wt. % NaCl equivalent, respectively. Accordingly, the first-generation apatite showed higher homogenization temperature and salinity than the second-generation apatite. The low salinity of the second-generation apatite could be related to mixing magmatic fluids with meteoric waters in the late stages of mineralization. Finally, baxsed on the geological, mineralogical, geochemical and fluid inclusion evidences, the iron oxide–apatite mineralization at the Bafq mextallogenic Zone was found to resemble with Kiruna‐type iron oxide-apatite (IOA) deposits, where a mix of magmatic and hydrothermal processes contributed to the formation of such deposits.
Keywords:
#Iron oxide-apatite #geochemistry #fluid inclusion #magmatic-hydrothermal #Kiruna-type #Bafq.
Keeping place: Central Library of Shahrood University
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Keeping place: Central Library of Shahrood University
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