What is the undercut of rock along the base of a cliff face called?
Wave-cut platforms
Wave-cut platforms form when destructive waves hit against the cliff face, causing an undercut between the high and low water marks, mainly as a result of abrasion, corrosion and hydraulic action, creating a wave-cut notch. This notch then enlarges into a cave.
What is cliff undercutting?
From International Dictionary of Marine Aids to Navigation. 7-4-280. Wave action at the base of cliffs removing material leaving the upper part overhanging, eventually leading to collapse.
How are coastal cliffs formed?
Cliffs are usually formed because of processes called erosion and weathering. Weathering happens when natural events, like wind or rain, break up pieces of rock. In coastal areas, strong winds and powerful waves break off soft or grainy rocks from hardier rocks. The harder rocks are left as cliffs.
What are coastal cliffs called?
abrasion coast
A cliffed coast, also called an abrasion coast, is a form of coast where the action of marine waves has formed steep cliffs that may or may not be precipitous. It contrasts with a flat or alluvial coast.
Why are there stripes on a cliff face near the beach?
These stripes vary in colour at different heights above the beach level. They reflect the colonisation of the rock surface by different kinds of organism. They represent groups of plants and animals which are more able or less able to live where they are subject to exposure to air and to sea water.
What is a coastal terrace?
A raised beach, coastal terrace, or perched coastline is a relatively flat, horizontal or gently inclined surface of marine origin, mostly an old abrasion platform which has been lifted out of the sphere of wave activity (sometimes called “tread”).
Is a sea cliff erosion or deposition?
Cliffs are often found along shores where wave erosion rather than deposition is the dominant coastal process. As waves attack the shore, headlands are eroded, producing steep sea cliffs.
How are undercutting formed?
Undercutting takes place all around the headland. The caves are deepened and widened on both sides of the headland until eventually the sea cuts through the headland, forming an arch. The rock at the top of the arch becomes unsupported as the arch is enlarged, eventually collapsing to form a stack .
What are cliffs made out of?
Cliffs are usually composed of rock that is resistant to weathering and erosion. The sedimentary rocks that are most likely to form cliffs include sandstone, limestone, chalk, and dolomite. Igneous rocks such as granite and basalt also often form cliffs.
How were cliffs of Moher formed?
During the time of their formation between 313 and 326 million years ago, a river dumped sand, silt and clay into an ancient marine basin. Over millions of years, the sediments collecting at the mouth of this ancient delta were compacted and lithified into the sedimentary strata preserved in the now-exposed cliffs.
What is sea cliff in geography?
Sea cliffs are steep faces of rock and soil that are formed by destructive waves. Waves crashing against the coastline erode until a notch is formed. The erosion of this notch undercuts the ground above it until it becomes unstable and collapses.