Relative Sea-Level Changes In Atlantic Canada: Observed Level and Sedimentological Changes Vs. Theoretical Models1
D.B. Scott, R. Boyd, F.S. Medioli, 1987. "Relative Sea-Level Changes In Atlantic Canada: Observed Level and Sedimentological Changes Vs. Theoretical Models", Sea-Level Fluctuation and Coastal Evolution, Dag Nummedal, Orrin H. Pilkey, James D. Howard
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Geophysical models propose that a former path of ice retreat can be divided into sea-level zones based on the thickness of ice over the region. The predicted position of these zones fits remarkably closely to the observed positions.
Fifteen different, detailed curves of relative sea level have been obtained in the Atlantic Canadian area and three composite curves derived from these data are presented here. These data exhibit highest resolution in the last 4,000 yrs, but one area provides a complete record since deglaciation and two other sites provide data from 7.0 ka to the present. A clear trend is apparent in these data: relative sea-level rise is greater seaward of the former ice margin with no former shorelines above present sea level. As one moves across the former ice margin toward the former ice center, there is evidence of early sea-level fall but no raised marine features. Closer to the ice center, old raised shorelines appear but present sea level is rising. Close to the former ice center, relative sea level is still falling with no evidence of any past relative sea-level rise.
Atlantic Canada demonstrates the complex inter-relationships which can develop over short distances between relative sea level and resulting sedimentation. For interpretation of relative sea level and sedimentation history in glacial regions, it is critical to locate the position of maximum glacial advance. Finding this position helps delineate the boundary between original areas of erosion and deposition and determines sources and quantities of sediment as sea level modifies a coastline. It also determines whether glacial deposition will be concentrated in terrestrial, continental shelf or continental slope and rise environments.
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Sea-Level Fluctuation and Coastal Evolution - This Special Publication is the result of a symposium in honor of W. Armstrong Price held at the first SEPM Midyear Meeting at San Jose, California, on August 12, 1984. The factors controlling relative sea-level change along our shores are varied and, at best, imperfectly understood. Yet, the relative rate of change is what controls shoreline erosion, the arrangement of sedimentary facies of the coastal zone, and the character of deformities within the coastal stratigraphic record. Therefore, these papers address sea-level changes, shoreline responses, and the controls on the three-dimensional geometry of the consequent lithosomes; in short, the architecture of the coastal depositional systems.