Coastal zone

COASTAL ZONE (EN: coast line, shore line, coastal zone; DE: Kustenzone; FR: zone littorale; ES: zona litoral, linea de costa; RU: береговая зона) is the region of the interaction among the dry land and water body (water flow), which comprises the shore proper (the part above the water), shore line, and coastal slope (the part under the water, the coastal shelf). The width of the coastal zone is from several tens of metres to several kilometres. The major factors, which are determining the character of the coastal zone, are the geological ones, climatic ones, engineering activity of the people, and so on.

The coastal zone

The coastal zone is formed by the sands, pebbles (accumulative phases), coarse clastic and crushed gravel material (abrasion phase), and depositions, which are brought by the rivers and winds from the interior of the continents onto the sea coast. The coastal zone forms itself during the water erosion by the waves of the surface and underwater slopes. The clastic material on the coast is subjected to the impact of the waves of the surf, tides and ebbs, and so on, under the influence of which there proceed the movement of the material along the coasts, its sorting, abrasion, and ejection onto the shore. As the result of this process, there emerge on the accumulative places the placers of the adjacent coastal shelf, of the surf zone, the littoral ones, and the placers of the above-water and under-water deltas within the mouths of the rivers, less often the aeolian and deflationary ones. The largest of them form themselves prevalently during the slow transgressions and regressions of the sea.

The examples of the large placers within the coastal zone are the deposits of the ilmenite, rutile, zircon, monazite (the eastern coast of Australia, and others), diamonds (the Atlantic coast of Africa), gold (Alaska, and others), cassiterite (Indonesia, Malaysia, and others), magnetite (Brazil, and others), amber (the coast of the Baltic sea). There are practically inexhaustible within the coastal zone the reserves of the sand and gravel, which are extracted within many coastal regions with the help of the marine dredges and land dredges. The mining works within the coastal zone are, as a rule, associated with the disturbance of the ecological balance, because of this there are conducted within the zone of the mining works the nature protection measures, which include the filling of the goaf space with the waste rock, the shutting of the boreholes, the restoration of the vegetation cover, and so on. Within the coastal zone, they perform the protection of the fauna, eliminate the dumping of the wastes, free flowing of the drilled wells, perform the filling of the artificial beaches and shores.