Section 8 Marine Littoral Systems

Abstract

The coast is a zone of interaction between processes of erosion and deposition in the sea and on the land. The changes which various coasts are undergoing, long term retreat and short term cliff erosion, are dependent on the character of the coasts. A classification of coastal Geounits involves the disciplines of oceanography and climatology in addition to geology. The coastal geomorphologic system, one of the largest, comprises 23 Units and nine Variants ordered in eight Subgroups: Br – Bedrock littorals are shorelines that are at the landward limit of marine processes on a rock coast (Figs. 66, 67). Bb – Residual shorelines are bluffs, steep banks ramping 5 to 50 m in height in unconsolidated sediments. Bw –Wave and current formed sediments are beaches and offshore sand bars (Figs. 68 to 71). Bl – Sea ice related forms are shore and beach materials that are moved by ice beyond the competence of other processes (Fig. 72). Bf – Holocene coral reefs are underwater structures made by marine organisms that secrete calcium carbonate (Figs. 73 to 75). Bt – Tidal regime deposits are tide-borne sediments that are deposited in protected bodies of coastal waters such as lagoons (Figs. 76, 77). Bc – Coastal plains are emerged portions of continental shelves (Figs. 78 to 81). Bp – Carbonate platforms are carbonate blankets in warm shallow waters of continental shelves in low latitudes.