CGRG Bibliography of Canadian Geomorphology
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Author : Brookes, I.A.
Date : 2006.
Title : Discussion on Deglacial History of Northern St. George’s Bay.
Publication : Current Research (2006). Newfoundland and Labrador Department of Natural Resources Geological Survey, Report
Issue : 06-1:
Page(s) : 33-47.
Abstract
Brookes - Following three seasons of work in the 1960s studying the glaciation of the St. George’s Bay area, during which I had vacillated in my interpretation of the meaning of striae for the sequence of ice-flow directions in 1968, I happened upon a partly till-mantled bedrock exposure at Campbells Creek, on the south shore of Port au Port Peninsula, where the reason for my previous indecision was clear. MacClintock and Twenhofel (1940) had interpreted crossing striae on bedrock along the north shore of St. George’s Bay as produced in the “Wisconsin” glaciation, first by southward flow of Labrador ice, succeeded by westward flow of Newfoundland ice following retreat of the former. At Campbells Creek (NTS map area 12B/10 - Stephenville, UTM 3627/53763), only stronger, deeper, westward striae appeared to me at first to “cross” northerly ones, suggesting younger inscription. Yet, on detailed examination, it became clear that southerly striae appeared to have been “crossed” by westerly ones because they had failed to register across the westerly striae, where the latter were the more deeply inscribed. Therefore, I concluded that the earliest late Wisconsinan ice flow had been from the Newfoundland ice cap, westward across Port au Port Peninsula, and was followed by southwesterly and southerly flow in the same ice-cap as its margin was indented by a calving bay, having a northern edge, parallel to the south shore of the peninsula (Brookes, 1970). I have found since, that a similar explanation, where glacial striae failed to inscribe the floor of a depression left by removal of a small bedrock chip, was called upon by Dawson (1875, Plate X, facing p. 207) in his examination of rare striae about the Missouri Coteau, during his survey with H.M. Boundary Commission 1873-74. At Campbells Creek and other localities along the southern shore of Port au Port Peninsula, the stronger striae are always the more westerly, and are more encompassing of bedrock relief, whereas more southerly striae are both weaker and more restricted to the tops of bedrock rises, which are commonly stromatoliths.
Bibliography of Canadian Geomorphology