Sea-Level Change and the Preservation Potential of Wave-Dominated and Tide-Dominated Coastal Sequences
Richard A. Davis, JR., H. Edward Clifton, 1987. "Sea-Level Change and the Preservation Potential of Wave-Dominated and Tide-Dominated Coastal Sequences", Sea-Level Fluctuation and Coastal Evolution, Dag Nummedal, Orrin H. Pilkey, James D. Howard
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The relative change in sea level and the rate of sediment input determine the character and the preservation potential of most coastal sequences, although wave and tidal energy, and geomorphic and geologic setting must also be considered. Progradational (regressive) coastal deposits are more likely to be fully preserved than those of transgressive coasts. Modern progradational coasts include numerous wave-dominated examples, (e.g., the Nayarit coast of Mexico, the Georgia Bight, and the Washington coast near the mouth of the Columbia River), and a few tide-dominated examples (e.g., the German Bight). In either situation, fairly complete shallowing-upward sequences of subtidal to supratidal facies are preserved, because the sedimentation rate exceeds dispersal by wave and/or tidal energy and the effect of rising or falling sea level.
Transgressive sequences, which form where relative sea-level rise exceeds net sediment accumulation, differ in degree of preservation. Wave-dominated transgressive systems include the present coast of Delaware and the outer banks of North Carolina. The Colorado River delta in the Gulf of California represents a tide-dominated transgressive coast. Under wave-dominated conditions, slow transgression with abundant sediment input and moderate or low-incident energy will allow much of the sequence to be preserved. A transgressive tide-dominated coast that is associated with low sediment influx from land is characterized by shoreward transport of subtidal sediment over the pre-existing facies. Present coastal conditions also produce geographically juxtaposed progradational and transgressive sequences, as on drumstick barriers. Such situations would generate a complicated stratigraphic record.
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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.