Headlands and bays

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"Bay" redirects here. For other uses, see Bay (disambiguation).

"Bays" redirects here. For other uses, see Bays (disambiguation).

For Headlands Center for the Arts, see Headlands Center for the Arts.

Headland on which lies the community of Argentia, on the island of Newfoundland, Canada

The bay at San Sebastián, Spain

The bay of Baracoa, Cuba

The bay of İzmir, in Turkey

A headland is an area of land adjacent to water on three sides. A bay is the reverse, rather an area of water bordered by land on three sides. A large headland may also be called a peninsula. Long, narrow and high headlands may be called promontories. When headlands dramatically affect the ocean currents they are often called capes. A large bay may also be called a gulf, sound or bight. A narrow bay may also be called a fjord if its sides are relatively steep. Any bay may include other bays (for example, James Bay is a bay within Hudson Bay).

1 Formation
2 Geology and geography
3 Beach Stability
4 List of some well-known headlands
5 List of some well-known bays
6 See also
7 External links

[edit] Formation

A headland is a piece of land that juts into the sea from the main land coast line. Headlands are shaped by erosion. They are formed when the sea attacks a section of coast consisting of alternating bands of hard and soft rock. The bands of soft rock such as sand and clay, erode more quickly than those of more resistant hard rock such as chalk. This would form a headland.

A bay is an area of water bordered by land on three sides. Bays are found between headlands where there are alternating outcrops of resistant rock and less resistant rock. Waves erode the areas of softer rock more rapidly than the hard rock to form bays.

[edit] Geology and geography

Headlands and bays are often found together on the same stretch of coastline. Headlands and bays form on discordant coastlines, where bands of rock of alternating resistance run perpendicular to the coast. Bays form where weak (less resistant) rocks (such as sands and clays) are eroded, leaving bands of stronger (more resistant) rocks (such as chalk, limestone, granite) forming a headland, or peninsula. Refraction of waves occurs on headlands concentrating wave energy on them, so many other landforms, such as caves, natural archs and stacks, form on headlands. Wave refraction disperses wave energy through the bay, and along with the sheltering effect of the headlands this protects bays from storms. This effect means that the waves reaching the shore in a bay are usually constructive waves, and because of this, many bays feature a beach. A bay may be only metres across, or it could be hundreds of kilometres across.

Sometimes bays form where movements of the earth's crust (tectonics) bring areas of land together, or move them apart. Usually these bays are referred to as seas or gulfs and not bays.

[edit] Beach Stability

Beaches are dynamic geologic features that can fluctuate between advancement and retreat of sediment. The natural agents of fluctuation include waves, tides, currents, and winds. Man-made elements such as the interruption of sediment supply, such as a dam, and withdrawal of ground fluid can also affect beach stabilization ^[1]. A headland bay beach can be classified as being in three different states of sedimentation. Static equilibrium refers to a beach that is stable and does not experience littoral drift or sediment deposition or erosion^[2]. Waves generally diffract around the headland(s) and near the beach when the beach is in a state of static equilibrium. Dynamic equilibrium occurs when the beach sediments are deposited and eroded at approximately equal rates^[3]. Beaches that have dynamic equilibrium are usually near a river that supplies sediment and would otherwise erode away without the river supply. Unstable beaches are usually a result of human interaction, such as a breakwater or dammed river^[4]. Unstable beaches are reshaped by continual erosion or deposition and will continue to erode or deposit until a state of equilibrium is reached in the bay.