Late Wisconsinan stratigraphy and chronology of southern St. George's Bay, Newfoundland: a re-appraisal: Discussion

Abstract

A sedimentological model has been presented by Bell et al. (2001) to explain the stratigraphy and chronology of glacigenic sediments at localities in southern St. George’s Bay, west Newfoundland. These authors claim that this model succeeds earlier interpretations of the sediments at these localities made by MacClintock and Twenhofel (1940) and Brookes (1969, 1974, 1977 a ), and, by implication, find fault with the history of late-glacial relative sea level for these localities and the wider area presented in Brookes (1974, 1977 a ) and, with some revision, in Forbes et al. (1993). This note draws attention to two points of difference I have with Bell et al. (2001) at the local and regional scales, namely the applicability of the adopted sedimentological model and the relation of the sediments concerned to late-glacial sea level. MacClintock and Twenhofel (1940) presented an inventory and interpretation of glacial and associated sediments exposed in tens of kilometres of coastal cliffs around St. George’s Bay (well portrayed in Bell et al. 2001, fig. 4). They divided the sediments into ( i ) a compact basal till, low in the cliffs, overlain in places by kame gravels — named “St. George’s River Drift,” ( ii ) an overlying marine sequence, comprising lower muds and higher deltaic sands and gravels, in places underlying a delta surface — named “Bay St. George Delta,” and ( iii ) in a few places, an upper unit of till and kame gravel, with morainic topography — named “Robinsons Head Drift.” The sequence was interpreted to have resulted from an ice advance beyond the present coast of the bay, followed by ice retreat and local stagnation at the present coast, then by marine submergence, and, finally, an ice readvance in several lobes across the present coastline into the sea and sediments previously deposited in it. Brookes (1969, 1974, 1977 …