Détail de la notice
Titre du Document
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)
HUDAK George J. ; MORTON Ronald L. ; FRANKLIN James M. ; ...
Résumé
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
Editeur
American Geophysical Union
Identifiant
ISSN : 0065-8448 CODEN : GPMGAD
Source
Geophysical monograph A. 2003, vol. 140, pp. 345-360 [16 pages] [bibl. : 2 p.1/4]
Langue
Anglais
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