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Titre du document / Document title

Morphology, distribution, and estimated eruption volumes for intracaldera tuffs associated with volcanic-hosted massive sulfide deposits in the Archean Sturgeon Lake Caldera complex, Northwestern Ontario

Auteur(s) / Author(s)

HUDAK George J. (1 2) ; MORTON Ronald L. (2) ; FRANKLIN James M. (3) ; PETERSON Dean M. (4 2) ;

Affiliation(s) du ou des auteurs / Author(s) Affiliation(s)

(1) Department of Geology, University of Wisconsin Oshkosh, Oshkosh, Wisconsin, ETATS-UNIS
(2) Department of Geosciences, University of Minnesota - Duluth, Duluth, Minnesota, ETATS-UNIS
(3) Franklin Geosciences Ltd., Nepean, Ontario, CANADA
(4) Economic Geology Group, Natural Resources Research Institute, Duluth, Minnesota, ETATS-UNIS

Résumé / Abstract

The Archean Sturgeon Lake Caldera Complex (SLCC) comprises a well-preserved, north-facing homoclinal sequence of greenschist facies metamorphosed intrusive, volcanic, and sedimentary strata. This piecemeal caldera complexis at least 25 km in strike length and contains nearly 3000 meters of dominantly subaqueously deposited intracaldera fill. Episodes of subaerial and subaqueous explosive felsic volcanism produced rhyodacitic to rhyolitic tuffs and lapilli tuffs. Progressing stratigraphically upward, the most voluminous are: a) the High Level Lake Tuff (∼16km3); b) the Mattabi Tuff (∼27km3); and c) the Middle L Tuff (∼7km3). The subaerially erupted, subaerially and locally subaqueously deposited High Level Lake Tuff comprises an 80-300 meter-thick unit composed of basal, poorly sorted, massive to normal graded, quartz-phyric, locally spherulitic tuffs and lapilli tuffs (30-150m thick) that are overlain by thin-bedded tuffs (<1-5m thick). The subaqueously erupted and deposited Mattabi Tuff contains up to thirteen individual flow units, each comprising two distinct depositional facies: a) lower, quartz-phyric, poorly sorted, ungraded, massive tuffs and lapilli tuffs (20-250 meters thick); and b) upper, laminated to medium bedded, typically normal graded tuffs (1-13 meters thick). The subaqueously erupted and deposited Middle L Tuff is also characterized by two distinct lithofacies: a) lower graded, quartz- and, rarely, potassium feldspar-phyric tuffs and lapilli tuffs (5-120m thick); and b) overlying, well-sorted, laminated to thickly bedded, normal graded tuffs (<1-5m thick). These three voluminous tuff deposits host all known volcanic-hosted massive sulfide (VHMS) ore bodies in the SLCC. At Sturgeon Lake, VHMS ore deposition appears to be favored by processes associated with the generation of voluminous subaqueous explosive eruptions.

Revue / Journal Title

Geophysical monograph    ISSN  0065-8448   CODEN GPMGAD 

Source / Source

2003, vol. 140, pp. 345-360 [16 page(s) (article)] (2 p.1/4)

Langue / Language

Anglais

Editeur / Publisher

American Geophysical Union, Washington, DC, ETATS-UNIS  (1956) (Revue)

Mots-clés anglais / English Keywords

Eastern Canada

;

North America

;

Canada

;

silicates

;

framework silicates

;

Precambrian

;

igneous rocks

;

volcanic rocks

;

pyroclastics

;

Ontario

;

Sturgeon Lake

;

feldspar

;

potassium

;

lithofacies

;

quartz

;

lapilli

;

volcanism

;

strike

;

greenschist facies

;

calderas

;

Archean

;

sulfides

;

tuff

;

explosive eruptions

;

ore bodies

;

Mots-clés français / French Keywords

Canada Est

;

Amérique du Nord

;

Canada

;

Silicate

;

Tectosilicate

;

Précambrien

;

Roche ignée

;

Roche volcanique

;

Pyroclastite

;

Ontario

;

Lac Sturgeon

;

Feldspath

;

Potassium

;

Lithofaciès

;

Quartz

;

Lapilli

;

Volcanisme

;

Ligne directionnelle

;

Facies schiste vert

;

Caldeira

;

Archéen

;

Sulfure

;

Tuf volcanique

;

Eruption explosive

;

Morphologie gîte

;

Mots-clés espagnols / Spanish Keywords

Canadá Este

;

America del norte

;

Canada

;

Silicato

;

Roca ignea

;

Roca volcánica

;

Ontario

;

Feldespato

;

Potasio

;

Litofácies

;

Cuarzo

;

Facies esquisto verde

;

Caldera

;

Arqueano

;

Sulfuro

;

Toba volcánica

;

Localisation / Location

INIST-CNRS, Cote INIST : 8310, 35400011908234.0220

Nº notice refdoc (ud4) : 15398943



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