Metasomatic crystallization of muscovite in granite and tourmaline in schist related to pegmatite emplacement near Yellowknife, Canada

Kretz, Ralph; Hartree, R.; Jones, Peter Tom

doi:10.1007/bf00375340

Cited by 17 publications

(5 citation statements)

References 13 publications

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“…Several examples from global pegmatites showed that the pegmatites rich in rare metals (U, Th and REEs) are associated with volatiles and/or fluids during late-stage, high temperature magmatic processes that assist in partitioning the elements (U, Th, REEs) out of the primary pegmatite zone and into the final residual fluids (Cerny et al 1986;Stern et al 1986;Simmons et al 1987;Plant et al 1999;Cuney and Kyser 2009). Metasomatic interaction between pegmatites and host rock has been the focus of many investigations that describe the processes in which host rock interactions enrich the pegmatite margins in U, Th, and REEs accessory phases (e.g., Williams, 1987;Owen 1989;Kretz et al 1989;Lentz 1996).…”

Section: Discussionmentioning

confidence: 99%

Field Features, Mineral assemblages and Geochemistry of Radioactive Pegmatite in the Wadi Abu Zawal Area, North Eastern Desert, Egypt

Hamid

2022

Egyptian Journal of Geology

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Section: Discussionmentioning

confidence: 99%

Field Features, Mineral assemblages and Geochemistry of Radioactive Pegmatite in the Wadi Abu Zawal Area, North Eastern Desert, Egypt

Hamid

2022

Egyptian Journal of Geology

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“…The margins of the quartz veins and the pegmatites observed at the Ptarmigan and Tom deposits typically have tourmaline-rich rims. [52] suggests that boron rich vapors were channelized along fractures that preceded pegmatite emplacement. An early boron-rich vapor likely deposited the 5-10 % concentrations of tourmaline observed in the Ptarmigan vein.…”

Section: Trace Element Substitutionmentioning

confidence: 99%

Apatite Composition and U-Pb Geochronology from the Ptarmigan and Tom Deposits, NWT Canada; Implications for Petrogenesis

Richardson¹,

Cr²,

Lentz³

et al. 2021

Preprint

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The Ptarmigan and Tom mesothermal gold deposits are located 10 km to the northeast of the city of Yellowknife, Northwest Territories in northern Canada. Both gold deposits comprise a series of en echelon veins that are hosted within upper greenschist to lower amphibolite facies ~2630 Ma (peak) rocks. Supracrustal units across the craton are intruded by the ca. 2610–2605-Ma granodiorite, tonalite, monzodiorite, quartz diorite, and affiliated rocks of the Concession Suite. Hydrothermal apatite is a common accessory mineral in both mineralized and non-mineralized quartz veins in the metasedimentary host rocks that constitute the Ptarmigan and Tom deposits. This study characterizes and compares turbidite-hosted hydrothermal apatite from the Ptarmigan and Tom deposits, non-mineralized veins adjacent to the ore body, and magmatic apatite from proximal LCT-pegmatites. Using electron probe microanalyses (EPMA), laser ablation inductively coupled plasma-mass spectrometry (LA-ICP-MS), micro-XRF, and cathodoluminescence (CL), the major, minor, and trace element abundances have been quantified and mapped. In addition to utilizing this data to determine if the chemistry of apatite can be used to constrain the source of hydrothermal fluids, the apparent age of the apatite is also evaluated utilizing in situ U-Pb dating. The distribution and abundance of major, minor, and trace elements from in situ recovered apatite were studied to characterize the nature of mineralizing ﬂuids. Most apatite from mineralized and non-mineralized veins show different Mn, Sr, and Pb contents, as well as chondrite-normalized rare-earth element (REE) and Y abundance patterns. REEs display five unique chondrite-normalized patterns: (1) negative sloped pattern with slight negative Eu anomaly, (2) a flat pattern with a positive Eu anomaly, (3) a positive slope with a negative Eu anomaly, (iv) light rare earth element (LREE) depleted pattern with positive Eu anomaly, and (v) bell-shaped pattern with a negative Eu anomaly. The REE patterns reflect both the source of the auriferous hydrothermal fluids and, perhaps, co-precipitating mineral phases. Apatite from the Ptarmigan vein occurs with both: (1) a flat pattern with a positive Eu anomaly and (2) bell-shaped pattern with a negative Eu anomaly. The bell-shaped and flat patterns typify orogenic gold deposits. Vein-hosted apatite commonly displays compositional zoning with a characteristic yellow cathodoluminescence (CL) emission spectra with darker cores and brighter rims. The cores have lower REE, whereas the rims are notably higher in REE. It is thought that the darker cores in CL images reflect a transition from an early low REE hydrothermal fluid to one enriched in REE. The hydrothermal apatite age of 2585 ± 15 Ma is consistent with the intrusions of the 2605 and 2590 Ma two-mica granites of the Prosperous Suite and associated LCT pegmatites.

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“…Nesse tipo de ambiente, os turmalinitos formam-se, principalmente, por metassomatismo de rochas pelíticas aluminosas. Em alguns casos, somente o boro é introduzido (Kretz et al 1989); em outros, o metassomatismo introduz Si, Fe, Mg, Al, Ca, enquanto o P, Na, K, Ba, Sr e o Rb são comumente removidos (Black 1971, Shearer et al 1984, Kretz et al 1989.…”

Section: Turmalinitosunclassified

ORIGEM DOS TURMALINITOS AURÍFEROS DA REGIÃO SUDESTE DO QUADRILÁTERO FERRÍFERO-MG: GEOLOGIA, PETROGRAFIA, QUÍMICA MINERAL E ISÓTOPOS DE Nd

Cavalcanti¹,

Xavier

2006

RBG

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Resumo Os turmalinitos auríferos que ocorrem na região do Anticlinal de Mariana, sudeste do Quadrilátero Ferrífero, têm suscitado debates quanto à sua origem, podendo ser singenética e relacionada a focos exalativos ou epigenética e atribuída a processos metamórficos ou a magmatismo granítico. O estudo realizado nos depósitos auríferos de Passagem, Mata Cavalo, Scliar e Chico Rei mostrou que existem três modos de ocorrência da turmalina associada aos depósitos auríferos da região: (T1) turmalina em corpos de turmalinitos estratiformes; (T2) turmalina nos halos de alteração hidrotermal das encaixantes da mineralização; e (T3) turmalina em veios mineralizados. Apesar das diferenças composicionais, a turmalina foi classificada como dravita, pertencente ao grupo das turmalinas alcalinas. A correlação entre os dados de campo, petrografia, química mineral e os isótopos de Nd indicou que: i) a circulação profunda de fluidos gerou focos exalativos ricos em boro, que resultaram na precipitação do turmalinito estratiforme; ii) a formação da turmalina dos halos de turmalinização e dos veios mineralizados está relacionada com a mistura de fluidos mobilizados das rochas encaixantes e daqueles provenientes do sistema mineralizante.

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Metasomatic crystallization of muscovite in granite and tourmaline in schist related to pegmatite emplacement near Yellowknife, Canada

Cited by 17 publications

References 13 publications

Field Features, Mineral assemblages and Geochemistry of Radioactive Pegmatite in the Wadi Abu Zawal Area, North Eastern Desert, Egypt

Field Features, Mineral assemblages and Geochemistry of Radioactive Pegmatite in the Wadi Abu Zawal Area, North Eastern Desert, Egypt

Apatite Composition and U-Pb Geochronology from the Ptarmigan and Tom Deposits, NWT Canada; Implications for Petrogenesis

ORIGEM DOS TURMALINITOS AURÍFEROS DA REGIÃO SUDESTE DO QUADRILÁTERO FERRÍFERO-MG: GEOLOGIA, PETROGRAFIA, QUÍMICA MINERAL E ISÓTOPOS DE Nd

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