Mineralogy, Geochemistry and Stable Isotope Studies of the Dopolan Bauxite Deposit, Zagros Mountain, Iran

Abstract

Abstract:The Dopolan deposit is a Mediterranean-type bauxite located in the Zagros Fold-Thrust Zone, Iran. This deposit consists of five lithological members including iron-rich, clay-rich, oolitic, pisolitic and organic matter-containing bauxites. The mineralogy of the deposit includes diaspore, boehmite, and kaolinite, nacrite, with minor pyrite, anatase and rutile. Geochemical studies show that light rare earth elements (LREEs) are enriched relative to heavy rare earth elements (HREEs) in all members, supporting an authigenic origin. Mass changes based on Ti as an immobile element indicate that conventionally-immobile elements (Al, Nb, Ta, Zr, Hf) are enriched in situ in the residual units, whereas mobile elements (K, Ca, Si) were depleted during bauxitization. This study shows that the Khaneh-Kat argillitic dolomite is the likely parent rock. The δ 18 O (7.63‰to 9.35‰) and δD values (´49.91‰to´66.49‰) for kaolinite in the bauxite samples suggest equilibration with meteoric waters which supports a supergene origin. Bauxitization occurred in a warm climate with relatively constant isotopic composition suggesting climate stability during the development of bauxite horizons and remobilization of Al (with formation of secondary boehmite). The δ 13 C values of calcite (´7.3‰) in the bauxite support the idea that the Khaneh-Kat Formation has experienced post-depositional isotope exchange with meteoric waters during the karstification process.

Provenance and Tectonic Evolution of Bauxite Deposits in the Tethys: Perspective From Random Forest and Logistic Regression Analyses

“…Thus, the contents of Al and Ti, which are mainly sourced from the continental basement, should be relatively stable during the whole formation process of bauxite. This is confirmed by the high correlation between Al and Ti in most bauxite deposits (e.g., Ellahi et al., 2016; Mameli et al., 2007; Xiong et al., 2021; Yang, Huang, et al., 2019).…”

Geochemical Characteristics and Toxic Elements in Alumina Refining Wastes and Leachates from Management Facilities

“…The concentration of SO 4 2− ranges from 502.5–6593.0 mg/L, which is 2.0 to 26.4 times higher than the recommended value of USEPA (GW) and China (GW) (250 mg/L). Pyrite (FeS 2 ) in bauxite is likely the primary source of SO 4 2− [38].…”

Mineralogical and Geochemical Features of Cretaceous Bauxite from San Giovanni Rotondo (Apulia, Southern Italy): A Provenance Tool

“…As a consequence, an enrichment of REEs in bauxite is indicative of the prevalence of alkaline conditions during its evolution [41]. Measuring variations in the La/Y ratio is a useful geochemical tool for determining changes in pH during bauxitization [42]. Values of La/Y <1 imply the prevalence of acidic conditions, whereas values of La/Y >1 indicate basic conditions.…”