Late Wisconsinan stratigraphy and chronology of southern St. George’s Bay, Newfoundland: a re- appraisal
Abstract: Almost sixty years after the initial mapping of extensive Quaternary sediments along the coast of St. George’s Bay, Newfoundland, a revised stratigraphic section is presented which identifies five main sediment types (diamicton, mud, sand, gravelly sand, gravel) and their stratigraphical p...
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| Format: | Text |
| Language: | English |
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.464.9984 http://www.mun.ca/geog/people/faculty/tbell/PDF_16.pdf |
| Summary: | Abstract: Almost sixty years after the initial mapping of extensive Quaternary sediments along the coast of St. George’s Bay, Newfoundland, a revised stratigraphic section is presented which identifies five main sediment types (diamicton, mud, sand, gravelly sand, gravel) and their stratigraphical position along 39 km of coastline from High-lands to Flat Bay. Most of the sediments overlying a basal till (St. George’s River Drift) are interpreted to have been deposited in an ice-proximal to ice-distal glaciomarine environment by debris flow, underflow, current flow, or suspen-sion settling, and capped by glaciofluvial outwash (Bay St. George Delta). For the most part, sections display a rela-tively simple deglacial sequence in a shallowing marine to fluvial environment. Where hummocky ridges intersect the coast, however, the sedimentary sequences are more complex and the variability in depositional style is typical of grounding line fans at a tidewater glacier margin. The occurrence of an upper diamicton or coarse gravels (Robinsons Head Drift) was generally observed only in grounding-line fan sequences and is interpreted here in the context of mar-ginal fluctuations of a quasi-stable tidewater glacier, and not necessarily a climatically-induced readvance of a land-based ice margin (Robinsons Head readvance). Radiocarbon dates on marine shells from varied stratigraphic positions and sedimentary units suggest rapid deposition occurred in a glaciomarine environment between 14 and 13 ka BP. Résumé: Près de soixante ans après la cartographie initiale de sédiments quaternaires largement répandus le long de la côte de la baie St. George, à Terre-Neuve, nous présentons une section stratigraphique révisée qui identifie cinq types |
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