The Vanadium-bearing Oxide Minerals of the Green Giant Vanadium-graphite Deposit, Southwest Madagascar

Cecco, Veronica E. Di; Tait, K. T.; Spooner, E. T. C.; Scherba, Craig

doi:10.3749/canmin.1700068

Cited by 6 publications

(2 citation statements)

References 22 publications

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“…In similar geological environments with reducing conditions (graphite-bearing metamorphic series), only V 3+ and V 4+ have been detected, such as in tanzanite, a V-bearing variety of zoisite, Ca 2 Al 3 (Si 2 O 7 )(SiO 4 )O(OH), from Merelani, northeast Tanzania (Olivier, 2006), as well as in the V-rich oxide minerals of the Green Giant vanadium-graphite deposit, southwest Madagascar (Di Cecco et al, 2018). In the Kola region (Russia), various V minerals contain exclusively V 3+ (Kompanchenko et al, 2018).…”

Section: Oxidation State Of Vanadiummentioning

confidence: 99%

Polygenic chamosite from a hydrothermalized oolitic ironstone (Saint-Aubin-des-Châteaux, Armorican Massif, France): crystal chemistry, visible–near-infrared spectroscopy (red variety) and geochemical significance

et al. 2020

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Several generations of chamosite, including a red variety, occur in the Ordovician hydrothermalized oolitic ironstone from Saint-Aubin-des-Châteaux (Armorican Massif, France). Their chemical re-examination indicates a low Mg content (0.925 < Fe/(Fe + Mg) < 0.954), but a significant variation in IVAl. Minor vanadium is present at up to 1.1 wt.% oxide. Variations in IVAl, the vanadium content and the colour of chamosite are related to the hydrothermal reworking of the ironstone. Taking into account other published data, the ideal composition of chamosite is (Fe5–xAl1+x)(Si3–xAl1+x)O10(OH)8, with 0.2 < x < 0.8 (0.2: equilibrium with quartz; 0.8: SiO2 deficit). The red chamosite (IIb polytype) has a mean composition of (Fe3.87Mg0.23Mn0.01□0.07Al1.74V0.07)(Si2.33Al1.67)O10(OH)8. This chamosite is strongly pleochroic, from pale yellow (E || (001)) to deep orange red (E ⊥ (001)). Visible–near-infrared absorbance spectra show a specific absorption band centred at ~550 nm for E ⊥ (001), due to a proposed new variety of Fe/V intervalence charge-transfer mechanism in the octahedral sheet, possibly Fe2+ – V4+ → Fe3+ – V3+. While the formation of green chamosite varieties is controlled by reducing conditions due to the presence of organic matter as a buffer, that of red chamosite would indicate locally a weak increase of fO2 related to oxidizing hydrothermal solutions.

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Section: Oxidation State Of Vanadiummentioning

confidence: 99%

Polygenic chamosite from a hydrothermalized oolitic ironstone (Saint-Aubin-des-Châteaux, Armorican Massif, France): crystal chemistry, visible–near-infrared spectroscopy (red variety) and geochemical significance

et al. 2020

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“…ниже). Исключение составляет месторождение Зеленый Гигант (Green Giant), Мадагаскар [Di Cecco et al, 2018], где карелианит входит в ассоциацию высокотемпературных гнейсов с другими V-и V-Ti-оксидами (если минерал действительно образован в прогрессивный этап).…”

Section: обсуждение результатов судя по присутствию включений карелиаunclassified

НЕПРЕРЫВНЫЙ ИЗОМОРФНЫЙ РЯД КАРЕЛИАНИТ–ЭСКОЛАИТ, ЖЕЛЕЗИСТЫЙ КАРЕЛИАНИТ И ТВЕРДЫЙ РАСТВОР ЭСКОЛАИТ–ГЕМАТИТ–КАРЕЛИАНИТ В МЕТАМОРФИЧЕСКИХ ПОРОДАХ СЛЮДЯНСКОГО КОМПЛЕКСА (Южное Прибайкалье)

2019

GiG

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В Cr-V-содержащих метаморфических породах слюдянского кристаллического комплекса установлен широкий изоморфный ряд от эсколаита с 98 мас. % Cr2O3 до карелианита с 93 мас. % V2O3. Оксиды ряда карелианит-эсколаит кристаллизовались в прогрессивную стадию высокотемпературного (гранулитовая фация) регионального метаморфизма и участвовали в образовании других хром-ванадиевых и Cr-V-содержащих минералов парагенезиса. Железистые карелианиты (до 12 мас. % Fe2O3) и трехкомпонентные твердые растворы Esk12-50Kar45-60Hem6-30 образованы в метаморфитах со специфичным составом протолита (Fe-Kar) и в метасоматитах, развитым по метаморфическим породам ((Cr,V,Fe)2O3). В статье дается обзор генетических типов природных эсколаита и карелианита и сопоставляются условия их кристаллизации с экспериментальными данными по синтезу.

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Vanadium ore resources of the African continent: State of the Art

Boni

Bouabdellah

Boukirou

et al. 2023

Ore Geology Reviews

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The Vanadium-bearing Oxide Minerals of the Green Giant Vanadium-graphite Deposit, Southwest Madagascar

Cited by 6 publications

References 22 publications

Polygenic chamosite from a hydrothermalized oolitic ironstone (Saint-Aubin-des-Châteaux, Armorican Massif, France): crystal chemistry, visible–near-infrared spectroscopy (red variety) and geochemical significance

Polygenic chamosite from a hydrothermalized oolitic ironstone (Saint-Aubin-des-Châteaux, Armorican Massif, France): crystal chemistry, visible–near-infrared spectroscopy (red variety) and geochemical significance

Vanadium ore resources of the African continent: State of the Art

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