Abstract: Comparison of Coastal Dynamics on West- and East-Facing Beaches in Magdalen Islands, Gulf of St. Lawrence, Canada

E. H. Owens

Comparison of time-series data collected on west- and east-facing barrier beaches in summer and winter on the Magdalen Islands shows variations in wave-energy levels and in littoral and inner nearshore-zone morphology which reflect exposure to wave-generated processes that result from the dominant and prevailing northwest winds. On the exposed west coast a "summer-winter" beach cycle results from a seasonal variation in wave-energy levels that is comparable to other west-coast environments such as California. The sheltered east-coast barrier is characterized by variable levels of wave energy related to storm-wave activity rather than to seasonal changes in the wave climate. This latter beach environment is similar to that on the northeast coast of the United States.

The important distinction between these two coastal environments is that cycles of erosion and deposition in the littoral and inner nearshore zones are on different time scales. The exposed west-coast environment has an annual cycle controlled by the wave climate whereas the sheltered east coast is a storm-wave environment in which variations in morphology are related to the intensity and frequency of storms. The results of this study of an enclosed microtidal sea correlate closely with other data from west- and east-facing coasts in North America and Europe.

AAPG Search and Discovery Article #90972©1976 AAPG-SEPM Annual Convention and Exhibition, New Orleans, LA