Minerals of the rhabdophane group and the alunite supergroup in microgranite: products of low-temperature alteration in a highly acidic environment from the Velence Hills, Hungary

Ondrejka, Martin; Bačík, Peter; Sobocký, Tomáš; Uher, Pavel; Škoda, Radek; Mikuš, Tomáš; Luptáková, Jarmila; Konečný, Petr

doi:10.1180/mgm.2018.137

Cited by 12 publications

(7 citation statements)

References 50 publications

(79 reference statements)

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“…Assemblages reflect a combination of igneous, metasomatic, and superimposed weathering-biogenic stages, as illustrated by the textural and compositional variety displayed by all REE-minerals. The observed compositional variation in key mineral groups agrees with prior work elsewhere on low temperature alteration processes (e.g., pyrochlore group, [37,38]), or rhabdophane [39,40]).…”

Section: Discussionsupporting

confidence: 87%

Mineralogy and Distribution of REE in Oxidised Ores of the Mount Weld Laterite Deposit, Western Australia

et al. 2023

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The Mount Weld rare earth element (REE) deposit, Western Australia, is one of the largest of its type on Earth. Current mining exploits the high-grade weathered goethite-bearing resource that lies above, and which represents the weathering product of a subjacent carbonatite. The mineralogy, petrography, deportment of lanthanides among the different components, and variation in mineral speciation, textures, and chemistry are examined. Microanalysis, involving scanning electron microscope (SEM) imaging, electron probe microanalysis (EPMA) and laser ablation inductively coupled-plasma mass spectrometry (LA-ICP-MS), was conducted on sized fractions of three crushed and ground laterite ore samples from current and planned production, and a representative sample from the underlying carbonatite. High-magnification imaging of particles in laterite samples show that individual REE-bearing phases are fine-grained and extend in size well below the micron-scale. Nanoscale inclusions of REE-phosphates are observed in apatite, Fe-(Mn)-(hydr)oxides, and quartz, among others. These have the appearance, particularly in fluorapatite, of pervasive, ultrafine dusty domains. Apart from the discrete REE minerals and abundant nano- to micron-scale inclusions in gangue, all ore components analysed by LA-ICP-MS contain trace to minor levels of REEs within their structures. This includes apatite, where low levels of REE are confirmed in preserved igneous apatite, but also Fe- and Mn-(hydr)oxides in which concentrations of hundreds, even thousands of ppm are measured. This is significant given that Fe-(Mn)-(hydr)oxides are the most abundant component of the laterite and points to extensive mobility and redistribution of REEs, and especially HREE, during progressive lateritisation. Late-formed minerals, notably tiny grains of cerianite, reflect a shift to oxidising conditions. REE-fluorocarbonates are the main host for REEs in carbonatite and are systematically replaced by hydrated, Ca-bearing REE-phosphates (largely rhabdophane). The latter displays varied compositions but is characteristically enriched in HREE relative to monazite in the same sample. Fine-grained, compositionally heterogeneous rhabdophane is accompanied by minor amounts of other paragenetically late, hydrated phosphates with enhanced MREE/HREE relative to LREE (although still LREE-dominant). Minor, relict xenotime and zircon are significant HREE carriers. Ilmenite and pyrochlore group members contain REE but contribute only negligibly to the overall REE budget. Although the proportions of individual mineral species differ, the chemistry of key ore components are similar in different laterite samples from the current resource. Mineral signatures are, however, subtly different in the lower grade southeastern part of the deposit, including higher concentrations of HREE relative to LREE in monazite, rhabdophane, florencite and Fe-(Mn)-(hydr)oxides.

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Section: Discussionsupporting

confidence: 87%

Mineralogy and Distribution of REE in Oxidised Ores of the Mount Weld Laterite Deposit, Western Australia

et al. 2023

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“…Allanite-(Ce) and zircon are the principal early magmatic phases of the hypersolvus to transsolvus granites (Uher et al 2009). Finally, an assemblage of low-temperature to supergene rhabdophane-group minerals, alunite-supergroup minerals, goethite and associated clay minerals were detected in the Velence microgranite (Ondrejka et al 2018a).…”

Section: Geological Setting and Review Of Petrographical And Mineralogical Datamentioning

confidence: 99%

“…Moreover, analogous granite to rhyolite pebbles to boulders commonly occur as clasts in Cretaceous to Palaeogene flysch conglomerate beds of the Pieniny Klippen Belt. Their petrography, rock-forming and accessory minerals as well as basic geochemical characteristics were investigated by many authors Uher and Gregor 1992;Broska et al 1993;Uher and Marschalko 1993;Uher et al , 2002aUher et al , 2009Uher et al , 2015Uher et al , 2018aUher andBroska 1994, 1996;Petrík et al 1994Petrík et al , 1995Buda and Nagy 1995;Broska and Uher 2001;Gyalog and Horváth 2004;Demko and Hraško 2013;Ondrejka et al 2015, b;Sobocký et al 2020). Monazite chemical and multi-zircon isotope dating revealed their Permian to Triassic age (Cambel et al 1977;Uher and Pushkarev 1994;Kotov et al 1996;Putiš et al 2000Putiš et al , 2016Putiš et al , 2019aFinger et al 2003;Lelkes-Felvári and Klötzli 2004;Radvanec et al 2009;Vozárová et al 2009Vozárová et al , 2012Vozárová et al , 2016Demko and Hraško 2013;Sobocký et al 2020;Szemerédi et al 2020a).…”

Section: Among Others)mentioning

confidence: 99%

Permian A-type granites of the Western Carpathians and Transdanubian regions: products of the Pangea supercontinent breakup

Ondrejka

Uher

Putiš

et al. 2021

Int J Earth Sci (Geol Rundsch)

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Permian biotite leucogranites to granite porphyries and rhyolites form small intrusions in several Alpine tectonic units in the Western Carpathians and the Pannonian region (Slovakia and Hungary). Their A-type signature is inferred from main- and trace-element geochemistry, with high K, Rb, Y, REE, Zr, Th, Nb, Fe/Mg and Ga/Al, low Al, Mg, Ca, P, Sr, V and strong negative Eu-anomaly. This geochemical signature is further supported by the mineralogy comprising local hypersolvus alkali feldspars, annitic biotite and the presence and composition of HFSE accessory minerals. The δ18O values measured for zircon (mean value 8.3 ‰ ± 0.36) may be explained by the melting of igneous material of crustal origin and/or mantle basalts which interacted with low-temperature fluids. The in-situ SHRIMP U–Pb isotope dating of zircon from the granites highlights two different periods of magmatic crystallisation and pluton emplacement: the older 281 ± 3 Ma Cisuralian age in the southern part, Velence Hills in the Pannonian region (Transdanubian Unit) and younger Guadalupian ages in the northern part, the West-Carpathian area: 262 ± 4 Ma (Turčok, Gemeric Unit), 267 ± 2 Ma (Hrončok, Veporic Unit) and 264 ± 3 Ma (Upohlav, granitic pebbles in Cretaceous conglomerates of the Pieniny Klippen Belt). The ~ 280 to 260-Ma interval is simultaneous with post-orogenic or anorogenic, rift-related and mainly alkaline (A-type) magmatism on the broader European scale. Our study documents a close relationship between the Permian continental rifting and the Neotethyan Meliatic oceanic basin opening in the Middle Triassic. The A-type granites originated from the partial melting of the ancient lower crustal quartzo-feldspatic rocks with the possible contribution of meta-basic material from the mantle in an extensional tectonic regime consistent with disintegration of the Pangea supercontinent during the Permian–Triassic period.

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“…2007; Ondrejka et al, 2018), the effect of phosphorus on the formation of tourmaline can be neglected. However, the role of fluorine is worth examining.…”

Section: Discussionmentioning

confidence: 99%

Tourmalines of the Velence Granite Formation and the surrounding contact slate, Velence Mountains, Hungary

Fehér

Zajzon

2021

CEuGeol

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Three distinct paragenetic and compositional types of tourmaline were described from the Velence Granite and the surrounding contact slate. Rare, pitch-black, disseminated tourmaline I (intragranitic tourmaline) occurs in granite, pegmatite, and aplite; very rare, black to greenish-gray, euhedral tourmaline II (miarolitic tourmaline) occurs in miarolitic cavities of the pegmatites; abundant, black to gray, brown to yellow or even colorless, acicular tourmaline III (metasomatic tourmaline) occurs in the contact slate and its quartz-tourmaline veins. Tourmaline from a variety of environments exhibits considerable variation in composition, which is controlled by the nature of the host rock and the formation processes. However, in similar geologic situations, the composition of tourmaline can be rather uniform, even between relatively distant localities. Tourmaline I is represented by an Al-deficient, Fe3+-bearing schorl, which crystallized in a closed melt-aqueous fluid system. Tourmaline II is a schorl-elbaite mixed crystal, which precipitated from Li- and F-enriched solutions in the cavities of pegmatites. Tourmaline III shows an oscillatory zoning; its composition corresponds to schorl, dravite, and foitite species. It formed from metasomatizing fluids derived from the granite. This is the most abundant tourmaline type, which can be found in the contact slate around the granite.

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Minerals of the rhabdophane group and the alunite supergroup in microgranite: products of low-temperature alteration in a highly acidic environment from the Velence Hills, Hungary

Cited by 12 publications

References 50 publications

Mineralogy and Distribution of REE in Oxidised Ores of the Mount Weld Laterite Deposit, Western Australia

Mineralogy and Distribution of REE in Oxidised Ores of the Mount Weld Laterite Deposit, Western Australia

Permian A-type granites of the Western Carpathians and Transdanubian regions: products of the Pangea supercontinent breakup

Tourmalines of the Velence Granite Formation and the surrounding contact slate, Velence Mountains, Hungary

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