ABSTRACT: Sedimentary characteristics of the coastal environment of North Point, Ontario

CGRG Bibliography of Canadian Geomorphology
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Abstract

North Point is a 2-3 km wide promontory underlain by crystalline Paleozoic carbonates and locally, in swales, by gray silty shales of the early post-glacial Tyrrell Sea. Several environments have developed around the promontory ranging from intensely ice-gouged rocky intertidal areas on the crest, to wide tidal flats and marshes in protected areas to the north, and wide sandy flats locally separated from the marshes by longitudinal beach ridges to the south. ... The physico-chemical properties of the intertidal and salt marsh sediments are strongly influenced by tides, and many exhibit lateral gradients associated with the frequency and duration of tidal inundation. Negative correlations between sand and silt content ... and positive correlations between clay content and elevation ... reflect the well developed sequence of landward fining in grain size which is directly related to tidal deposition. In the salt marsh the sediments are alsoaffected by vegetation, topography and drainage pattern. Strong seasonal changes occur in chemical properties of the sediments, but there are nonetheless well-defined trends. Elevation of the marsh is positively correlated with organic carbon content ... and negatively correlated with pH ... and electrical conductivity, although this last variable varies greatly depending on tidal inundation, precipitation and evaporation. There exist strong lateral differences in average Eh which are associated with drainage patterns. Reducing conditions are consistently recorded in marsh zones which retain standing water, have high electrical conductivities and are subject to frequent tidal inundation

Bibliography of Canadian Geomorphology