Rare Earth, Major, and Trace Element Geochemistry of Surface and Geothermal Waters from the Taupo Volcanic Zone, North Island New Zealand

Hannigan, Robyn

doi:10.1007/1-4020-3234-x_3

Cited by 9 publications

(3 citation statements)

References 38 publications

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“…Therefore, the high-temperature circulating groundwater in Kamado may have had the ability to take much magnesium from ultrabasic or/and magnesium-rich carbonate rocks into the surface lakes [62]. In contrast, the exceedingly low REE contents of banded ores and massive ores may crystallize at lower temperatures [63,64], and aqueous solution conditions for plateau lakes with alkalinity (pH > 7) [65] support the obvious assumption that Mg 2+ is derived from ultramafics, which are poor in REEs [27,66,67].…”

Section: Magnesium Sources Of the Kamado Magnesite Depositmentioning

confidence: 99%

Genesis of the Large-Scale Kamado Magnesite Deposit on the Tibetan Plateau

Yu,

Hu,

Chen

et al. 2023

Minerals

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Lacustrine strata-bound magnesite deposits associated with Alpine-type ultramafic rocks are hydrothermal in origin. The magnesite ores of the Kamado deposit are unconformably underlain by mid-Jurassic marine carbonate and ultramafic rocks of the Bangong-Nujiang ophiolite suite and are in fault contact with hanging wall rocks composed of siliceous sinter. Three types of cryptocrystalline magnesite ores can be identified in Kamado: (1) strata-bound massive magnesites, representing the main ore type in the upper part; (2) banded ores in the lower part; and (3) some vein and stockwork ore in the ultramafic wall rocks. Integrated scanning electron microscopy, C–O isotope analysis, and geochemical analyses were carried out on the Kamado deposit. The results indicate that: (1) the orebody is composed of magnesite, with accessory minerals of aragonite, opal, and chromite; (2) the siliceous sinter and relatively high B (32.0–68.1 ppm) and Li (14.7–23.4 ppm) contents of the magnesite ores reflect long-term spring activity in Kamado; (3) the light carbon (δ13CV-PDB: −4.7 ± 0.3‰ to −4.1 ± 0.6‰) and oxygen isotopic compositions (δ18OV-SMOW: +12.3 ± 0.3 to +16.3 ± 0.1‰) of the stockwork ores in the foot wall rocks indicated that the carbon in fractures in the ultramafic rocks is from a mixture of marine carbonate and oxidized organic-rich sedimentary rocks, reflecting a typical “Kraubath-type” magnesite deposit; and (4) the relatively heavy carbon isotopic (δ13CV-PDB: +8.7 ± 0.4‰ to +8.8 ± 0.3‰) composition of the banded magnesite ores in the lower segment may have formed from heavy CO2 generated by anaerobic fermentation in the lakebed. Additionally, the carbon isotopic (δ13CV-PDB: +7.3 ± 0.3‰ to +7.7 ± 0.7‰) composition of the massive magnesite ores in the upper segment indicates a decline in the participation of anaerobic fermentation. As this economically valuable deposit is of the strata-bound massive ore type, Kamado can be classified as a lacustrine hydrothermal-sedimentary magnesite deposit, formed by continuous spring activities under salt lakes on the Tibetan Plateau, with the Mg mainly being contributed by nearby ultramafic rocks and the carbon mainly being sourced from atmosphere-lake water exchange, with minor amounts from marine carbonate strata.

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Section: Magnesium Sources Of the Kamado Magnesite Depositmentioning

confidence: 99%

Genesis of the Large-Scale Kamado Magnesite Deposit on the Tibetan Plateau

Yu,

Hu,

Chen

et al. 2023

Minerals

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“…Alguns autores (ZHOU et al, 2005;HANNIGAN, 2005;JOHANNESSON et al, 2005, TANG e JOHANNESSON, 2005 observaram que o padrão ETR das rochas dos aquíferos assemelha-se aos das águas por elas armazenadas. Dessa forma, os ETR seriam potenciais rastreadores da interação água/rocha.…”

Section: Influência Da Rocha Hospedeiraunclassified

“…Dentre eles estão os elementos terras raras (ETR), que podem apresentar semelhanças composicionais aos das rochas hospedeiras (SMEDLEY, 1991;ZHOU et al, 2005;HANNIGAN, 2005;JOHANNESSON et al, 2005, TANG e JOHANNESSON, 2005.…”

Section: Introductionunclassified

Elementos terras raras e urânio em águas subterrâneas sob influência de aquíferos distintos em Campinas (SP)

Bulia

Enzweiler

2015

R. Águas Subter.

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Resumo: A composição química de águas subterrâneas resulta, em parte, de reações água-rocha nos respectivos aquíferos. Dentre os vários constituintes das águas, os elementos terras raras (ETR) e urânio podem ser traçado-res de processos geoquímicos e de fluxos hidrológicos. O principal objetivo deste trabalho foi procurar associações entre as assinaturas químicas de águas subterrâneas extraídas de três sistemas aquíferos distintos (cristalino, sedimentar e diabásio) e suas respectivas rochas hospedeiras. As amostras foram coletadas a partir de quatro poços tubulares do campus da Universidade Estadual de Campinas (Campinas, SP), nas quais foram determinados parâmetros físico-químicos, íons principais e elementos-traço, incluindo os ETR. Os resultados indicam que a água de dois poços (IMECC e IB) é predominantemente influenciada pelos aquíferos cristalino e diabásio, enquanto a dos outros dois (GM e FEF) pelo aquífero sedimentar. Os valores individuais e normalizados dos ETR nos quatro poços são distintos entre si, evidenciando a heterogeneidade da geologia local. A água de um poço (GM) apresentou concentrações de urânio superiores ao valor máximo permitido vigente para água potável. O U na água provavelmente resulta da dissolução oxidativa de fase(s) com U presente(s) no aquífero sedimentar. Entretanto, a modelagem hidroquímica indicou Ca 2 UO 2 (CO 3 ) 3 e CaUO 2 (CO 3 ) 2 2-como as principais espécies de U dissolvidas, as quais são consideradas não tóxicas e não biodisponíveis, conforme dados da literatura. Palavras-chave:Hidrogeoquímica. Interação Água-Rocha. Elementos Terras Raras. Urânio. Modelagem de Águas Subterrâneas. Abstract:The composition of groundwaters results mainly from water-rock reactions within aquifers. Among the various constituents of water, the rare earth elements (REE) and uranium can serve as tracers of geochemical processes and hydrological flow paths. The main objective of this study was to associate the chemical composition of groundwaters extracted from three distinct aquifer systems (crystalline, diabase and sedimentary) with that of the respective hosts rocks. The area of the study is located at the campus of University of Campinas (Campinas, SP). Samples of groundwater collected from four tubular wells were used to determine physicochemical parameters, major ions and trace elements, including the REE. The results confirm that the water of two wells (IMECC and IB) is predominantly influenced by the crystalline and diabase aquifers, while the other two (GM and FEF) by the sedimentary aquifer. Both the individual and normalized REE values of the four wells are distinct from each other, pointing to the heterogeneity of the local geology. The uranium concentration in the water of one well (GM) exceeded the guideline value for this element in drinking water. The U probably results from the oxidative dissolution of U-bearing phases in the sedimentary aquifer. However, the hydrochemical modeling indicated Ca 2 UO 2 (CO 3 ) 3 and CaUO 2 (CO 3 ) 2 2-as the major U dissolved species, which ar...

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