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In: The Coastline of Canada, S.B. McCann. (Ed.); Geological Survey of Canada. 1980, 293-301 GEOMORPHOLOGY OF SOUTHWESTERN JAMES BAY: A LOW ENERGY, EMERGENT COAST I.P. MARTINI1, D.W. COWELL2, and G.M. WICKWARE2 1Department of Land Resource Science, University of Guelph, Ontario
 The
southwestern coastline of Hudson and James bays in Ontario and Manitoba is
the longest low gradient, emergent shoreline in the world. It maintains an
uninterrupted offshore slope of about 0.5-1 m/km over a distance of
approximately 1700 km. The land has been subjected to active rebound for
the last 7000-8000 years, and is still rising at a rate of less than 1
m/100 years. The Ontario coast consists of three main morphologies: coasts dominated by abundant parallel beach ridges and spits; coasts dominated by estuarine systems; and coasts with promontories and transverse ridges. All three types of coastlines are represented in the southern part of James Bay. Longitudinal beach ridges fringe upper tidal flats on the southern and eastern sides of promontories and in areas where storm waves are not greatly attenuated by extensive sandy flats. The longitudinal ridges vary in elevation from 1.5-2 m (composite sandy and gravelly ridges), to 0.3-0.5 m (coastal single sandy bars), and in sandy flats to 0.2 m (sinusoidal sand waves). Promontories and transverse ridges are related to bedrock highs or glacial depositional features modified by deposition of coastal sands and gravels. A marked counter-clockwise marine current in the southern part of James Bay redistributes the fluviatile materials to the southeast of estuaries, onto extensive, featureless, low lying tidal flats. With emergence, incorporation of these features into the peatland complex is manifested through a progressive paludification of the landscape, and in older parts of the Lowland. Only high ridges and promontories (higher than 1 m) with well-developed coniferous forests, remain as recognizable coastal landforms.
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