A. Abedini; A. Oroji; A. A. Calagari
Abstract
Thekaolinizedzonesof the Goorgoor area (north of Takab, West-Azarbaidjan province) are alteration products of andesitic rocks of Miocene age in northwest of Iran. Based on the mineralogical studies, kaolinite, quartz, jarosite, montmorillonite, albite, muscovite-illite, anatase, chlorite, orthoclase, ...
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Thekaolinizedzonesof the Goorgoor area (north of Takab, West-Azarbaidjan province) are alteration products of andesitic rocks of Miocene age in northwest of Iran. Based on the mineralogical studies, kaolinite, quartz, jarosite, montmorillonite, albite, muscovite-illite, anatase, chlorite, orthoclase, calcite, goethite and hematite are mineral phases in these zones. The silicic veins existing within these zones include metallic minerals such as pyrite, chalcopyrite, galena, sphalerite, bornonite, and stibnite. The mass change calculations of rare earth elements (REEs), with assumption of Sc as a monitor immobile element, reveal that development of kaolinization processes were accompanied by enrichment-depletion of La-Nd and depletion of Sm-Lu. Geochemical analyses show that the degree of differentiation of Al from Fe and destruction of zircon by hydrothermal fluids are the most important controlling factors for variation of Eu (0.84-1.06) and Ce (0.83-0.93) anomalies in these zones, respectively. Positive and strong correlations of (La/Lu)N and (LREEs/HREEs)N values with components such as P, S, LOI, and Sr establish the effective role of hypogene solutions in progression of kaolinization processes. The combination of the obtained results from mineralogical and geochemical investigations suggest that changes in chemistry of altering solutions (e.g., pH and Eh) and diversity in type of fixing minerals are two key factors affecting differentiation and distribution of REEs in the kaolinizedzones at Goorgoor.
A Abedini; S Alipour; M Khosravi
Abstract
TheDarzi-Vali bauxite deposit is located in ~20 km east of Bukan, south of West-Azarbaidjan province (NW Iran). This deposit developed as stratiform layers and lenses within carbonate rocks of the Ruteh Formation (middle Permian). The mineralogical studies indicated that the surface waters with oxidizing-acidic ...
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TheDarzi-Vali bauxite deposit is located in ~20 km east of Bukan, south of West-Azarbaidjan province (NW Iran). This deposit developed as stratiform layers and lenses within carbonate rocks of the Ruteh Formation (middle Permian). The mineralogical studies indicated that the surface waters with oxidizing-acidic nature and the underground waters with reducing-basic nature played an important role during the development and evolution of this deposit. Based on field evidences and geochemical studies, the basaltic rocks are the most probable parent rock of this deposit. Calculations of enrichment factor revealed that the elements of Si, Ca, Mg, Na, K, Mn, Co, Rb and Hf were leached during development of this deposit and the elements of Al, Ti, V, Th, Ga, Zr, Nb, U, and Cr were enriched. This is while the elements of Fe, P, Ni, Ba, and Y have borne leaching-fixation processes. The obtained data indicated that the factors such as adsorption, scavenging, residual concentrations, buffering of weathering solutions by carbonate bedrock, mineralogical control, differences in intense of alteration, organic matter, and fluctuation of underground water tables have played pronounced roles in distribution of major, minor, and trace elements in this deposit. This study also revealed that the Fe-poor and Fe-rich ores of this deposit have appropriate properties for being used in refractory and cement industries, respectively.
F Kangarani Farahani; A.A Calagari; A Abedini
Abstract
Kambelu lateritic deposit is located in ~80 km west of Damghan, Semnan province. This deposit was developed as stratiform lenses along the contact of carbonates of Elika Formation (Triassic) and shale-sandstone of Shemshak Formation (Jurassic). Petrographical studies testify to the presence of collomorphic, ...
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Kambelu lateritic deposit is located in ~80 km west of Damghan, Semnan province. This deposit was developed as stratiform lenses along the contact of carbonates of Elika Formation (Triassic) and shale-sandstone of Shemshak Formation (Jurassic). Petrographical studies testify to the presence of collomorphic, colloformic, pseudo-porphyritic, and nodular textures within the ores of this deposit. Mineralogical data show that the ores contain diaspore, goethite, anatase, kaolinite, hematite, boehmite, and zircon. Considering the mineralogical composition and textural characteristics, this deposit was formed in an almost reduced near-surface environment. Geochemical indices like Eu/Eu* along with ratios such as Ti/Zr, Nb/Y, and Al/Ti suggest that Kambelu deposit is a product of alteration and weathering of rocks of trachy-andesitic to basaltic composition. Comparison of the variation trend of elements like Si, Al, and Fe within a selective profile reveals that the variation in chemistry (i.e., pH) of solutions responsible for lateritization and drainage intensity are the two principal factors for formation of the ores. Geochemical considerations show that distribution of trace elements in this deposit is a function of factors such as adsorption, scavenging by metallic oxides and hydroxides, fixation in neomorphic phases, and presence in resistant mineral phases. Inharmonic distribution of REEs in the studied profile indicates an allogenic origin for this deposit. The obtained data indicate that clays, anatase, zircon, xenotime, gorceixite, and churchite are the potential hosts for REEs in this deposit.
F Kangarani Farahani; A.A Calagari; A Abedini
Abstract
The Shahbolaghi laterite deposit is located in ~40 km southeast of Damavand, Tehran province. This deposit was developed as stratiform horizons within the shales and sandstones of Shemshak formation (Jurassic). Mineralogical investigations show that the major minerals in this deposit include hematite, ...
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The Shahbolaghi laterite deposit is located in ~40 km southeast of Damavand, Tehran province. This deposit was developed as stratiform horizons within the shales and sandstones of Shemshak formation (Jurassic). Mineralogical investigations show that the major minerals in this deposit include hematite, boehmite, and anatase accompanied by lesser amounts of goethite, magnetite, chamosite, kaolinite, quartz, calcite, diaspore, zircon, pyrite, and rutile. The microscopic evidences such as development of spastoidic textures within the ores suggest a high energy water-saturated sedimentary environment during the lateritization processes. By considering the mineral assemblage and textural characteristics, deposition and diagenesis of this horizon occurred in an oxidizing and almost near surface environment. Based on the obtained data from the field observations, geochemistry of major, trace, and rare earth elements the lateritic horizon at Shahbolaghiwas developed probably byalteration of parent rocks with basaltic composition. The bauxitization process was occurredintrends of kaolinization, destruction of kaolinite, and deferrugenization. The geochemical investigations indicated that the distribution of trace elements in this horizon was controlled by clays and minor mineral phases.
S Alipour; A Abedini; Sh Abdali
Abstract
The Heydar-Abad laterite horizon is located at 65 km south of Urmia, West Azarbaidjan province. This horizon was developed as stratiform bed within the carbonate rocks of the late Permian Ruteh Formation. Based on the petrographical and mineralographical studies,the ores of this horizon contain micro-granular, ...
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The Heydar-Abad laterite horizon is located at 65 km south of Urmia, West Azarbaidjan province. This horizon was developed as stratiform bed within the carbonate rocks of the late Permian Ruteh Formation. Based on the petrographical and mineralographical studies,the ores of this horizon contain micro-granular, fluidal-collomorphic, panidiomorphic-granular, spastoidic, pelitomorphic, nodular, and ooidic textures and have an authigenic origin. According to the mineralogical investigations, the ores of this horizon include minerals such as diaspore, corundum, hematite, magnetite, goethite, rutile, paragonite, margarite, amesite, berthierine, montmorillonite, chlorite, chloritoid, muscovite-illite, quartz, pyrite, anhydrite, calcite, and dolomite. The presence of high quantities of silicate minerals indicates immaturity and poor draining system during the development of this residual horizon. The results of chemical analyses show that Eu and Ce anomalies in the ores are within the ranges of 0.67 to 2.74 and 0.86 to 2.16, respectively. The calculations of values of enrichment factor of elements in two selected profiles reveal that two processes of leaching and fixation are major regulators of concentrations of REEs in ores of this horizon. The results obtained from the mineralogical and geochemical studies show that changes of pH of weathering solution, fluctuations of level of ground-waters, alteration intensity, and function of carbonate bedrocks as a geochemical barrier, adsorption, and scavenging have played an important role in distribution of the rare earth elements (REEs) in this deposit. The correlation coefficients show that the secondary phosphates, rutile and muscovite-illite are potential hosts for REEs in the ore.
M Roohafza; S Alipour; A Abedini
Abstract
Ghareh-bolagh area is located in 20 Km of east of Mahabad, south of West-Azarbaidjan province. Carbonate rocks of Bayandour formation and dolomites of Soltanieh formation in this area are the host of mineralizations from Barium, iron and manganese. Based upon mineralogical investigations, barite, magnetite, ...
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Ghareh-bolagh area is located in 20 Km of east of Mahabad, south of West-Azarbaidjan province. Carbonate rocks of Bayandour formation and dolomites of Soltanieh formation in this area are the host of mineralizations from Barium, iron and manganese. Based upon mineralogical investigations, barite, magnetite, hematite, goethite, limonite, pyrolusite were major mineral assemblages of these mineralizations which that is accompanied by chalcopyrite, malachite, azurite, and calcite in low amounts. The most important geochemical characteristic these mineralizations are relative weak differentiation of LREE from HREE in barite and iron-manganese ores, Eu negative anomalies in iron-manganese ores (0.26-0.76) and Eu positive anomalies in barite (7.7-10.51). Incorporation of the obtained results from investigations of field, petrographic and geochemical (analytic data and correlation coefficients between elements) indicate that factors such as changes in physicochemical conditions of environment (pH, Eh, temperature), activity of complexing ligands, and presence of minor mineral phases (clay minerals, zircon, zenotime, and monazite) played important role in distribution of rare earth elements during mineralization and development of these ores.
