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GEOREF RECORD

The nature and distribution of tantalum-bearing minerals in newly discovered, rare-element pegmatites at the Musselwhite Mine, northwestern Ontario

Richard P. Taylor and Rod Henham
The nature and distribution of tantalum-bearing minerals in newly discovered, rare-element pegmatites at the Musselwhite Mine, northwestern Ontario
Exploration and Mining Geology (April 2001) 10 (1-2): 85-93

Abstract

Newly discovered pegmatites distributed throughout the sub-surface environs of the Musselwhite Archean gold deposit occur as narrow dikes that intrude most of the major lithological units. The mineralogy and textures of the pegmatite dikes are characteristic of granitic pegmatites of the "Rare-Element Class"; more specifically, they closely resemble varieties of the "Complex-type" granitic pegmatites that are commonly associated with zones of tantalum mineralization. The essential minerals in the dikes comprise albite, quartz, and K-feldspar, together with lesser amounts of mica (including lepidolite), spessartine, tourmaline, and locally, spodumene. Fine-grained (30 mu m to 300 mu m), tantalum-bearing minerals occur in the quartzo-feldspathic matrix of the dikes as disseminations, in interstices, and in small vugs. The nature of the tantalum-bearing mineral assemblage present in individual pegmatite dikes varies from a simple mineral assemblage composed of ferrocolumbite (with around 39 wt % Ta (sub 2) O (sub 5) ) in the most northerly dike, to more complex assemblages comprised of manganotantalite (with up to 75 wt% Ta (sub 2) O (sub 5) ), ferrotapiolite (with up to 79 wt% Ta (sub 2) O (sub 5) ), and microlite (with up to 76 wt% Ta (sub 2) O (sub 5) ) that are present in dikes located several kilometers to the south and southwest. The compositional characteristics and textural relationships of the tantalum-bearing minerals in the dikes provide evidence of igneous fractionation trends that are typical of rare-element granitic pegmatites. Such trends suggest that the newly discovered pegmatites represent part of a more extensive group of cogenetic, tantalum-mineralized dikes.


ISSN: 0964-1823
Serial Title: Exploration and Mining Geology
Serial Volume: 10
Serial Issue: 1-2
Title: The nature and distribution of tantalum-bearing minerals in newly discovered, rare-element pegmatites at the Musselwhite Mine, northwestern Ontario
Affiliation: Carleton University, Department of Earth Sciences, Ottawa, ON, Canada
Pages: 85-93
Published: 200104
Text Language: English
Publisher: Canadian Institute of Mining, Metallurgy and Petroleum, Montreal, QC, Canada
References: 23
Accession Number: 2003-040428
Categories: Economic geology, geology of ore depositsIgneous and metamorphic petrology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. sect., 6 tables, geol. sketch maps
N53°00'00" - N53°00'00", W90°30'00" - W90°30'00"
Secondary Affiliation: Placer Dome (CLA), CAN, Canada
Country of Publication: Canada
Secondary Affiliation: GeoRef, Copyright 2018, American Geosciences Institute.
Update Code: 200313
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