Stratigraphy, sedimentology and paleogeography of Mississippian Strata of the Bay St. George Subbasin, western Newfoundland

• Main Author: Knight, I. (Ian)
• Format: Thesis
• Language: English
• Published: Memorial University of Newfoundland 1983
• Subjects: Cabot; Newfoundland
• Online Access: https://research.library.mun.ca/6963/; https://research.library.mun.ca/6963/1/Knight_Ian_Part1and2.pdf; https://research.library.mun.ca/6963/3/Knight_Ian_Part1and2.pdf

The Bay St. George subbasin is one of two major depressions filled by Carboniferous sediments in insular Newfoundland. It is the northeast extension of the larger Maritimes Basin. It contains approximately 10 km of sediments ranging in age from Late Devonian to Late Carboniferous of which strata of the Anguille Group (Famennian - Tournaisian age) and the Codroy Group (Visean age) are described here. Both groups contain mostly nonmarine terrigenous clastic sediments with marine strata only within the Codroy Group. -- The subbasin is believed to have formed as a pull-apart trough, rather than as a simple rift, adjacent to, and west of, the northeasterly trending Long Range fault, a major strike-slip structure that is part of the Hercynian Cabot Fault system in western Newfoundland. Dextral, strike-slip movements began in Middle or Late Devonian time and ended in Early Carboniferous (middle Visean) time. Three basin-fills, each approximately 3000 m thick, filled the pull-apart sequentially so that the oldest fill now occurs in the southwest and the youngest fill in the northeast. The first two basin-fills of Famennian and Tournasian age (Anguille Group), were deposited within an elongate, 30 km wide trough which initially formed between divergent faults near the southern margin of the Precambrian Steel Mountain anorthosite and which with time enlarged southwestward. The third basin-fill is made up of middle Visean strata (basal part of the Codroy Group). By this time, the subbasin had broadened to 60 km, and was irregular in shape, consisting of several subsiding depressions separated by fault-bounded archs. Wrench movements ceased in middle Visean time and the subbasin was subsequently influenced by block faulting when sediments of the upper part of the Codroy Group were deposited. -- The Anguille Group comprises Famennian redbeds (Kennels Brook Formation), and Tournaisian deepwater lacustrine black shales and mudstones, and turbidite and deltaic sandstones (Snakes Bight Formation), gray, fluvial-deltaic ...