Freshwater Bay, Isle of Wight, England-26Dec2013 (1)

coastal geography Coastal geography is the study of the constantly changing region between the ocean and the land, incorporating both the physical geography (i.e. coastal geomorphology, climatology and oceanography) and the human geography (sociology and history) ...

, a concordant, longitudinal, or Pacific type coastline occurs where

beds A bed is an item of furniture that is used as a place to sleep, rest, and relax. Most modern beds consist of a soft, cushioned mattress on a bed frame. The mattress rests either on a solid base, often wood slats, or a sprung base. Many be ...

, or layers, of differing

rock Rock most often refers to: * Rock (geology), a naturally occurring solid aggregate of minerals or mineraloids * Rock music, a genre of popular music Rock or Rocks may also refer to: Places United Kingdom * Rock, Caerphilly, a location in Wales ...

types are folded into

ridge A ridge or a mountain ridge is a geographical feature consisting of a chain of mountains or hills that form a continuous elevated crest for an extended distance. The sides of the ridge slope away from the narrow top on either side. The line ...

s that run parallel to the

coast The coast, also known as the coastline or seashore, is defined as the area where land meets the ocean, or as a line that forms the boundary between the land and the coastline. The Earth has around of coastline. Coasts are important zones in n ...

. The outer hard rock (for example,

granite Granite () is a coarse-grained (phaneritic) intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly cools and solidifies undergro ...

) provides a protective barrier to

erosion Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is distin ...

of the softer rocks (for example,

clay Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4). Clays develop plasticity when wet, due to a molecular film of water surrounding the clay par ...

s) further inland. Sometimes the outer hard rock is punctured, allowing the sea to erode the softer rocks behind. This creates a

cove A cove is a small type of bay or coastal inlet. Coves usually have narrow, restricted entrances, are often circular or oval, and are often situated within a larger bay. Small, narrow, sheltered bays, inlets, creeks, or recesses in a coast are o ...

, a circular area of water with a relatively narrow entrance from the sea.

Lulworth Cove Lulworth Cove is a cove near the village of West Lulworth, on the Jurassic Coast in Dorset, southern England. The cove is one of the world's finest examples of such a landform, and is a World Heritage Site and tourist location with approximately ...

Dorset Dorset ( ; archaically: Dorsetshire , ) is a county in South West England on the English Channel coast. The ceremonial county comprises the unitary authority areas of Bournemouth, Christchurch and Poole and Dorset (unitary authority), Dors ...

is situated on a concordant coastline. The outer hard rock is

Portland limestone Portland stone is a limestone from the Tithonian stage of the Jurassic period quarried on the Isle of Portland, Dorset. The quarries are cut in beds of white-grey limestone separated by chert beds. It has been used extensively as a building sto ...

. The sea has broken through this barrier and easily eroded the clays behind it. A

chalk Chalk is a soft, white, porous, sedimentary carbonate rock. It is a form of limestone composed of the mineral calcite and originally formed deep under the sea by the compression of microscopic plankton that had settled to the sea floor. Chalk ...

cliff face at the back of the cove slows further erosion. Erosion is just starting to the west, where the sea has again broken through the

barrier at

Stair Hole Stair Hole is a small cove located just west of Lulworth Cove in Dorset, southern England. The folded limestone strata known as the ''Lulworth crumple'' are particularly visible at Stair Hole. There are several caves visible from the seaward s ...

. The concordant coast may take one of two landform types. The Dalmatian type, named from

Dalmatia Dalmatia (; hr, Dalmacija ; it, Dalmazia; see #Name, names in other languages) is one of the four historical region, historical regions of Croatia, alongside Croatia proper, Slavonia, and Istria. Dalmatia is a narrow belt of the east shore of ...

on the

Adriatic Sea The Adriatic Sea () is a body of water separating the Italian Peninsula from the Balkan Peninsula. The Adriatic is the northernmost arm of the Mediterranean Sea, extending from the Strait of Otranto (where it connects to the Ionian Sea) to t ...

, features long offshore islands and coastal inlets that are parallel to the coastline. The Adriatic Sea itself is a concordant landform, consisting of a body of water between parallel ranges. These Dalmatian types normally occur in high energy environments from where there is eustatic or isostatic change creating a submerging coastline. The second landform is the Haff type as in the Haffs, or lagoons, of the southern shore of the

Baltic Sea The Baltic Sea is an arm of the Atlantic Ocean that is enclosed by Denmark, Estonia, Finland, Germany, Latvia, Lithuania, Poland, Russia, Sweden and the North and Central European Plain. The sea stretches from 53°N to 66°N latitude and from ...

, which are enclosed by long spits of sand parallel to the low coast. The converse of concordant coastline is a

discordant coastline A discordant coastline occurs where bands of different rock types run perpendicular to the coast. The differing resistance to erosion leads to the formation of headlands and bays. A hard rock type such as granite is resistant to erosion and cre ...

References

{{coastal geography Coastal geography

See also

References