The Quaternary history of the Carmanville (NTS 2E8) area, northeast Newfoundland

Munro, Mandy (1994) The Quaternary history of the Carmanville (NTS 2E8) area, northeast Newfoundland. Masters thesis, Memorial University of Newfoundland.

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Abstract

The Carmanville (NTS 2E/8) area is located in northeast Newfoundland. It is marked by a complex assemblage of sediments and landforms. These are in order of diminishing areal importance: till which has a variety of geomorphic expressions such as veneers, hummocks, ridges, and lineations; organic deposits; glaciofluvial sand and gravel (also meltwater channels); colluvial sediment; and fluvial deposits. -- Four ice flows are detected in the area: successively eastward, northeastward, northwestward, and northwestward. These are all argued to be Late Wisconsinan in age. Retreat and down-wasting of the third ice-flow, northwestward, was associated with large quantities of meltwater and the formation of the Ragged Harbour Moraine. This formed shortly after 12,000 BP. The final ice-flow event (also northwestward) may be correlative with the Younger Dryas cooling event dated to between approximately 11,000 and 10,000 BP. -- Till deposits are mainly formed by northwestward moving ice and are mostly fine-textured with high percentages of local clasts. They display only minor regional textural and lithological variations. All tills observed and analyzed are basal, and most are interpreted as melt-out or lodgment tills. -- The Ragged Harbour Moraine in the northeast of the study area is approximately 15km long and is composed of the most diverse sedimentary assemblage in the region. High angle-planar cross-bedded gravels, extensively deformed silts and sands, rhythmically and ripple bedded silts and sands, and diamictons are present within this complex and occur directly adjacent to each other. This sedimentary assemblage is interpreted as a sequence of subaqueous fans which formed proglacially under rapid sedimentation rates, while ice was stagnating. Rogen moraines formed contemporaneously with the Ragged Harbour Moraine. The moraine formation does not represent a lengthy stillstand of glacial ice. -- The marine limit in the area is at least 57m asl (above sea level) based on emerged marine sediment at Noggin Hill and Wing's Point. Five further major sea level stands occurred at 52m, 38m, 34m, 17m, and 11m asl indicated by the presence of emerged beaches. Two terraces at 5m and 2m asl are evident around most of the coastline but may represent major storm events rather than being representative of relative sea-level change. These sea-level stands all occurred between 12,500 and 10,000 BP, Sea levels dropped to below present during the mid-Holocene and then continued to rise until present times.

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