Genesis of REE minerals in the karstic bauxite in western Guangxi, China, and its constraints on the deposit formation conditions

Liu, Xuefei; Wang, Qingfei; Zhang, Qizuan; Zhang, Ying; Li, Yan

doi:10.1016/j.oregeorev.2015.12.015

Cited by 62 publications

(19 citation statements)

References 54 publications

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“…The present study illustrates this point, and economic concentrations of CE have been found in other weathering profiles, soils and laterites worldwide [8,10,11,[74][75][76][77]. In fact, it is well known that the mineral structures of aluminophosphates of the alunite supergroup, such as florencite or goyazite, can concentrate REE at economic grades in lateritised carbonatites and karstic bauxites [74,78,79]. Similar enrichments at subeconomic grades are also described in other carbonatites [80] and kimberlites [81].…”

Section: Weathered Phosphates As Non-conventional Source Of Critical supporting

confidence: 85%

Critical Elements in Supergene Phosphates: The Example of the Weathering Profile at the Gavà Neolithic Mines, Catalonia, Spain

et al. 2019

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The essential role of Critical Elements (CE) in 21st century economy has led to an increasing demand of these metals and promotes the exploration of non-conventional deposits such as weathering profiles. The present work is focused on the study of a weathering profile located at the Archaeological Park of the Gavà Neolithic Mines, Barcelona, Catalonia, Spain. In the Gavà deposit, acid and oxidising meteoric fluids generated intense weathering during the early Pleistocene, affecting series of Llandoverian black shales and associated syn-sedimentary phosphates. The circulation of these acid fluids at deeper levels of the profile generated supergene vein-like mineralisations comprised of secondary phosphates (e.g., variscite, perhamite, crandallite, phosphosiderite) and sulphates (e.g., jarosite, alunite). This supergene mineralisation is significantly enriched in certain CE (e.g., Ga, Sc, REE, In, Co and Sb) that were mobilised from host rock components and later hosted in the crystal lattice of supergene minerals. Weathering processes and corresponding supergene enrichment of CE at the Gavà deposit could be used as an example to determine exploration guidelines of CE in weathering profiles and associated supergene phosphates worldwide.

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Section: Weathered Phosphates As Non-conventional Source Of Critical supporting

confidence: 85%

Critical Elements in Supergene Phosphates: The Example of the Weathering Profile at the Gavà Neolithic Mines, Catalonia, Spain

et al. 2019

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“…Under these conditions, a classic enrichment in LREE and a depletion in HREE resulted in the precipitation of LREE-bearing fluoro-carbonates. In contrast, during the quaternary reworking of the bauxite in the karst networks, the strong pH and Eh variation triggered the LREE-fluoro-carbonates dissolution and, as a consequence, a significant decrease of the LREE/HREE ratio in the newly formed bauxite deposits [38]. Also, in the Abruzzi bauxite case study, the deposits likely underwent a multistage evolution that involved lateritization, erosion and reworking, and a relatively later bauxitization in situ also occurred in the karst networks.…”

Section: Genetic Processmentioning

confidence: 98%

“…Recent works successfully showed that the mineralogy of and geochemistry of REE can be controlled by the variation of pH and Eh [38], which can occur during several ore-forming stages that characterize the genesis of karst bauxites [38,48]. For example, in the Permian Longhe and Tianyang bauxite deposits (China) the in situ bauxitization was characterized by an alkaline and oxidizing environment (7 < ph < 10, −0.8 < Eh < 0, [42,49]).…”

Section: Genetic Processmentioning

confidence: 99%

Geochemical Characterization of Bauxite Deposits from the Abruzzi Mining District (Italy)

Putzolu¹,

Papa²,

Mondillo³

et al. 2018

Minerals

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Abstract:The Abruzzi bauxite district includes the deposits located on the Campo Felice plateau and those of the Monti d'Ocre, which had been mined in the first part of the 20th century. Bauxite is of the karst type, with textures ranging between oolitic and oolitic-conglomeratic, the latter suggesting a partial reworking of evolved lateritic soils. The high contents of Al 2 O 3 and Fe 2 O 3 (average values 53.76 and 21.76 wt %, respectively) are associated with the presence of boehmite, hematite, and minor goethite. SiO 2 and TiO 2 have average values of 7.79 and 2.75 wt %, corresponding to the presence of kaolinite, anatase and rutile. Among the minor so-called "bauxitophile" elements V, Co, Ni, Cr and Zr, the most enriched is Cr, with an average value of 0.07 wt %. Nickel has an average value of 210.83 ppm. Vanadium shows an average value of 266.57 ppm, whereas the average Co concentration is 35.89 ppm. The total rare earth elements (REE) concentration in the sampled bauxite sites is variable between ca. 700 and 550 ppm. Among REEs, the most abundant element is Ce, with Ce anomalies commonly associated with authigenic REE-fluoro-carbonates, probably produced after the REEs remobilization from primary detrital minerals and their precipitation in neo-formed phases during the bauxitization process. Scandium and Ga occur in small amounts (57 and 60 ppm, respectively), but geochemical proxies of their remobilization and uptake in neo-formed minerals (Feand Al-(hydr)oxides, respectively) have been observed. The mean Eu/Eu* and Al 2 O 3 /TiO 2 ratios and the Ni-Cr contents of the Abruzzi bauxites suggest that the parent rock of these deposits was a material of acid affinity, likely corresponding to volcanic tephra or eolic loess-type sands.

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“…However, REE fractionations and redistributions have been reported from various bauxite deposits due to evolution of geochemical systems in various mechanisms and conditions such as mobilization of REE, supergene processes, surficial weathering, diagenetic processes, presence of REEbearing mineral phases, pH of solutions and/or depositional environment, and existence of organic and/or non-organic complexing ligands (Mondillo et al, 2011;Abedini and Calagari, 2013;Mongelli et al, 2014Mongelli et al, , 2016Mongelli et al, , 2017Liu et al, 2016;Buccione et al, 2016;Hou et al, 2017;Khosravi et al, 2017;Long et al, 2017;Radusinovic et al, 2017;Torró et al, 2017;Yuste et al, 2017;Chen et al, 2018). Generally, these Fig.…”

Section: Introductionmentioning

confidence: 99%

Ree mobility and tetrad effects in bauxites an example from the Kanisheeteh deposit, NW Iran

Abedini¹

2019

Acta Geodynamica Et Geomaterialia

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The Kanisheeteh bauxite deposit (NW Iran) is located on the Irano-Himalaya karst bauxite belt and was developed as stratiform horizon along the contact of the Permian and Triassic Formations. Based on absolute weathering index (AWI), HREE were leached out, whereas LREE suffered both leaching and fixation during bauxitization. The non-CHARAC characteristic of Y/Ho ratios can be attributed to geochemically known phenomenon as the "tetrad effect". The simultaneous convex and concave curves of the tetrad effect were observed in the chondritenormalized REE patterns of the bauxite ores. The correlation between the sizes of T 4 and AWI% values revealed two separate populations. The first one is characterized by a wide variation in sizes of T 4 and very narrow AWI% values, and is thought to be related to acidic zone of the profile. In contrast, the second one is marked by a narrow variation in sizes of T 4 and wide variation in AWI% values, and is conceived to be affiliated to alkaline zone of the profile. In this research, the tetrad effect proved to be capable of clarifying the geochemical characteristics of the deposit and can be applied as a good geochemical index to investigate the prevailed paleoconditions of depositional environments.

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Genesis of REE minerals in the karstic bauxite in western Guangxi, China, and its constraints on the deposit formation conditions

Cited by 62 publications

References 54 publications

Critical Elements in Supergene Phosphates: The Example of the Weathering Profile at the Gavà Neolithic Mines, Catalonia, Spain

Critical Elements in Supergene Phosphates: The Example of the Weathering Profile at the Gavà Neolithic Mines, Catalonia, Spain

Geochemical Characterization of Bauxite Deposits from the Abruzzi Mining District (Italy)

Ree mobility and tetrad effects in bauxites an example from the Kanisheeteh deposit, NW Iran

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