Peninsula

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Satellite photos of peninsulas, top, left to right: The Fennoscandian Peninsula, the Floridian Peninsula, the Arabian Peninsula, and the Kola Peninsula

A peninsula (from Latin paeninsula ; from paene  'almost',and insula  'island') [1] [2] is a landform that extends from a mainland and is surrounded by water on most, but not all of its borders. [3] [4] [5] A peninsula is also sometimes defined as a piece of land bordered by water on three of its sides. [3] [6] Peninsulas exist on all continents. [7] [2] The size of a peninsula can range from tiny to very large. [7] The largest peninsula in the world is the Arabian Peninsula. [8] [9] Peninsulas form due to a variety of causes.

Contents

Etymology

Peninsula derives from Latin paeninsula , which is translated as 'peninsula'. Paeninsula itself was derived from paene  'almost',and insula  'island', or together, 'almost an island'. [3] The word entered English in the 16th century. [3]

Definitions

A peninsula is usually defined as a piece of land surrounded on most, but not all sides, [5] but is sometimes instead defined as a piece of land bordered by water on three of its sides. [6]

A peninsula may be bordered by more than one body of water, and the body of water does not have to be an ocean or a sea. [10] A piece of land on a very tight river bend or one between two rivers is sometimes said to form a peninsula, for example in the New Barbadoes Neck in New Jersey, United States. [5] A peninsula may be connected to the mainland via an isthmus, for example, in the isthmus of Corinth which connects to the Peloponnese peninsula. [11]

Formation and types

Peninsulas can be formed from continental drift, glacial erosion, glacial meltwater, glacial deposition, marine sediment, marine transgressions, volcanoes, divergent boundaries, and/or river sedimentation. [12] More than one factor may play into the formation of a peninsula. For example, in the case of Florida, continental drift, marine sediment, and marine transgressions were all contributing factors to its shape. [13]

Glaciers

In the case of formation from glaciers, (e.g. the Antarctic Peninsula or Cape Cod) peninsulas can be created due to glacial erosion, meltwater, and/or deposition. [14] If erosion formed the peninsula, softer and harder rocks were present, and since the glacier only erodes softer rock, it formed a basin. [14] This may create peninsulas, and occurred for example in the Keweenaw Peninsula. [14]

In the case of formation from meltwater, melting glaciers deposit sediment and form moraines, which act as dams for the meltwater. [14] This may create bodies of water that surround the land, forming peninsulas. [14]

If deposition formed the peninsula, the peninsula was composed of sedimentary rock, which was created from a large deposit of glacial drift. [15] [16] The hill of drift becomes a peninsula if the hill formed near water but was still connected to the mainland, for example during the formation of Cape Cod about 23,000 years ago. [17] [18]

Others

In the case of formation from volcanoes, when a volcano erupts magma near water, it may form a peninsula (e.g. the Alaskan Peninsula). [15] Peninsulas formed from volcanoes are especially common when the volcano erupts near shallow water. [19] Marine sediment may form peninsulas by the creation of limestone. [20] A rift peninsula may form as a result of a divergent boundary in plate tectonics (e.g. the Arabian Peninsula), [21] [22] while a convergent boundary may also form peninsulas (e.g. Gibraltar or the Indian subcontinent). [23] Peninsulas can also form due to sedimentation in rivers. When a river carrying sediment flows into an ocean, the sediment is deposited, forming a delta peninsula. [24]

Marine transgressions (changes in sea level) may form peninsulas, but also may affect existing peninsulas. For example, the water level may change, which causes a peninsula to become an island during high water levels. [25] Similarly, wet weather causing higher water levels make peninsulas appear smaller, while dry weather make them appear larger. [26] Sea level rise from global warming will permanently reduce the size of some peninsulas over time. [27]

Uses

Peninsulas are noted for their use as shelter for humans and Neanderthals. [28] The landform is advantageous because it gives hunting access to both land and sea animals. [28] They can also serve as markers of nation's borders. [29]

Abridged list of peninsulas

Europe

Africa

Asia

Australia

Americas

Antarctica

See also

Related Research Articles

<span class="mw-page-title-main">Glacier</span> Persistent body of ice that is moving under its own weight

A glacier is a persistent body of dense ice that is constantly moving under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires distinguishing features, such as crevasses and seracs, as it slowly flows and deforms under stresses induced by its weight. As it moves, it abrades rock and debris from its substrate to create landforms such as cirques, moraines, or fjords. Although a glacier may flow into a body of water, it forms only on land and is distinct from the much thinner sea ice and lake ice that form on the surface of bodies of water.

<span class="mw-page-title-main">Drumlin</span> Geological feature formed by glacial ice acting on underlying unconsolidated till or ground moraine

A drumlin, from the Irish word droimnín, first recorded in 1833, in the classical sense is an elongated hill in the shape of an inverted spoon or half-buried egg formed by glacial ice acting on underlying unconsolidated till or ground moraine. Assemblages of drumlins are referred to as fields or swarms; they can create a landscape which is often described as having a 'basket of eggs topography'.

<span class="mw-page-title-main">Till</span> Unsorted glacial sediment

Till or glacial till is unsorted glacial sediment.

Landforms are categorized by characteristic physical attributes such as their creating process, shape, elevation, slope, orientation, rock exposure, and soil type.

A kame delta is a glacial landform formed by a stream of melt water flowing through or around a glacier and depositing material, known as kame deposits. Upon entering a proglacial lake at the end (terminus) of a glacier, the river/stream deposit these sediments. This landform can be observed after the glacier has melted and the delta's asymmetrical triangular shape is visible. Once the glacier melts, the edges of the delta may subside as ice under it melts. Glacial till is deposited on the lateral sides of the delta, as the glacier melts.

<span class="mw-page-title-main">Deposition (geology)</span> Geological process in which sediments, soil and rocks are added to a landform or landmass

Deposition is the geological process in which sediments, soil and rocks are added to a landform or landmass. Wind, ice, water, and gravity transport previously weathered surface material, which, at the loss of enough kinetic energy in the fluid, is deposited, building up layers of sediment.

<span class="mw-page-title-main">Raised beach</span> Emergent coastal landform

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. Thus, it lies above or under the current sea level, depending on the time of its formation. It is bounded by a steeper ascending slope on the landward side and a steeper descending slope on the seaward side. Due to its generally flat shape, it is often used for anthropogenic structures such as settlements and infrastructure.

<span class="mw-page-title-main">Kettle (landform)</span> Depression/hole in an outwash plain formed by retreating glaciers or draining floodwaters

A kettle is a depression/hole in an outwash plain formed by retreating glaciers or draining floodwaters. The kettles are formed as a result of blocks of dead ice left behind by retreating glaciers, which become surrounded by sediment deposited by meltwater streams as there is increased friction. The ice becomes buried in the sediment and when the ice melts, a depression is left called a kettle hole, creating a dimpled appearance on the outwash plain. Lakes often fill these kettles; these are called kettle hole lakes. Another source is the sudden drainage of an ice-dammed lake. When the block melts, the hole it leaves behind is a kettle. As the ice melts, ramparts can form around the edge of the kettle hole. The lakes that fill these holes are seldom more than 10 m (33 ft) deep and eventually fill with sediment. In acid conditions, a kettle bog may form but in alkaline conditions, it will be kettle peatland.

<span class="mw-page-title-main">Outwash plain</span> Plain formed from glacier sediment that was transported by meltwater.

An outwash plain, also called a sandur, sandr or sandar, is a plain formed of glaciofluvial deposits due to meltwater outwash at the terminus of a glacier. As it flows, the glacier grinds the underlying rock surface and carries the debris along. The meltwater at the snout of the glacier deposits its load of sediment over the outwash plain, with larger boulders being deposited near the terminal moraine, and smaller particles travelling further before being deposited. Sandurs are common in Iceland where geothermal activity accelerates the melting of ice flows and the deposition of sediment by meltwater.

<span class="mw-page-title-main">Glacial landform</span> Landform created by the action of glaciers

Glacial landforms are landforms created by the action of glaciers. Most of today's glacial landforms were created by the movement of large ice sheets during the Quaternary glaciations. Some areas, like Fennoscandia and the southern Andes, have extensive occurrences of glacial landforms; other areas, such as the Sahara, display rare and very old fossil glacial landforms.

<span class="mw-page-title-main">Terminal moraine</span> Type of moraine that forms at the terminal of a glacier

A terminal moraine, also called end moraine, is a type of moraine that forms at the terminal (edge) of a glacier, marking its maximum advance. At this point, debris that has accumulated by plucking and abrasion, has been pushed by the front edge of the ice, is driven no further and instead is deposited in an unsorted pile of sediment. Because the glacier acts very much like a conveyor belt, the longer it stays in one place, the greater the amount of material that will be deposited. The moraine is left as the marking point of the terminal extent of the ice.

<span class="mw-page-title-main">Terrace (geology)</span> A step-like landform

In geology, a terrace is a step-like landform. A terrace consists of a flat or gently sloping geomorphic surface, called a tread, that is typically bounded on one side by a steeper ascending slope, which is called a "riser" or "scarp". The tread and the steeper descending slope together constitute the terrace. Terraces can also consist of a tread bounded on all sides by a descending riser or scarp. A narrow terrace is often called a bench.

<span class="mw-page-title-main">Tunnel valley</span> Glacial-formed geographic feature

A tunnel valley is a U-shaped valley originally cut under the glacial ice near the margin of continental ice sheets such as that now covering Antarctica and formerly covering portions of all continents during past glacial ages. They can be as long as 100 km (62 mi), 4 km (2.5 mi) wide, and 400 m (1,300 ft) deep.

<span class="mw-page-title-main">Rogen moraine</span> Landform of ridges deposited by a glacier or ice sheet transverse to ice flow

A Rogen moraine is a subglacially formed type of moraine landform, that mainly occurs in Fennoscandia, Scotland, Ireland and Canada. It is one of the three main types of hummocky moraines. They cover large areas that have been covered by ice, and occur mostly in what is believed to have been the central areas of the ice sheets. Rogen moraines are named after Lake Rogen in Härjedalen, Sweden, the landform's type locality. Rogen Nature Reserve serves to protect the unusual area.

<span class="mw-page-title-main">Table Mountain Sandstone</span> Group of rock formations within the Cape Supergroup sequence of rocks

The Table Mountain Sandstone (TMS) is a group of rock formations within the Cape Supergroup sequence of rocks. Although the term "Table Mountain Sandstone" is still widely used in common parlance, the term TMS is no longer formally recognized; the correct name is the "Peninsula Formation Sandstone", which is part of the Table Mountain Group. The designation "Table Mountain Sandstone" will, however, in deference to the title, continue to be used in the rest of this article. The name is derived from the famous landmark in Cape Town, Table Mountain.

Fluvioglacial landforms are those that result from the associated erosion and deposition of sediments caused by glacial meltwater. These landforms may also be referred to as glaciofluvial in nature. Glaciers contain suspended sediment loads, much of which is initially picked up from the underlying landmass. Landforms are shaped by glacial erosion through processes such as glacial quarrying, abrasion, and meltwater. Glacial meltwater contributes to the erosion of bedrock through both mechanical and chemical processes.

<span class="mw-page-title-main">Geology of Massachusetts</span>

The geology of Massachusetts includes numerous units of volcanic, intrusive igneous, metamorphic and sedimentary rocks formed within the last 1.2 billion years. The oldest formations are gneiss rocks in the Berkshires, which were metamorphosed from older rocks during the Proterozoic Grenville orogeny as the proto-North American continent Laurentia collided against proto-South America. Throughout the Paleozoic, overlapping the rapid diversification of multi-cellular life, a series of six island arcs collided with the Laurentian continental margin. Also termed continental terranes, these sections of continental rock typically formed offshore or onshore of the proto-African continent Gondwana and in many cases had experienced volcanic events and faulting before joining the Laurentian continent. These sequential collisions metamorphosed new rocks from sediments, created uplands and faults and resulted in widespread volcanic activity. Simultaneously, the collisions raised the Appalachian Mountains to the height of the current day Himalayas.

Old and Young Drift are geographic names given to the morainic landscapes that were formed in Central Europe; the Old Drift during the older ice ages and the Young Drift during the latest glaciations – the Weichselian in North Germany and the Würm in the Alps. Their landforms are quite different. Areas of Old Drift have been heavily flattened and transformed as a result of geomorphic processes such as denudation and erosion, whilst areas of Young Drift have largely retained their original shape. Whilst the majority of Old Drift moraines were formed during the Saale glaciation about 130,000 to 140,000 years ago, the Young Drift moraines in Central Europe are only about 15,000 to 20,000 years old. The terms Old and Young Drift are used for all elements of the glacial series even though the meltwater deposits and landforms are not strictly moraines.

A meltwater channel is a channel cut into ice, bedrock or unconsolidated deposits by the flow of water derived from the melting of a glacier or ice-sheet. The channel may form on the surface of, within, beneath, along the margins of or downstream from the ice mass. Accordingly it would be referred to as supraglacial, englacial, subglacial, lateral or proglacial.

<span class="mw-page-title-main">Glaciofluvial deposits</span> Sediments/deposits formed from ice sheets or glaciers

Glaciofluvial deposits or Glacio-fluvial sediments consist of boulders, gravel, sand, silt and clay from ice sheets or glaciers. They are transported, sorted and deposited by streams of water. The deposits are formed beside, below or downstream from the ice. They include kames, kame terraces and eskers formed in ice contact and outwash fans and outwash plains below the ice margin. Typically the outwash sediment is carried by fast and turbulent fluvio-glacial meltwater streams, but occasionally it is carried by catastrophic outburst floods. Larger elements such as boulders and gravel are deposited nearer to the ice margin, while finer elements are carried farther, sometimes into lakes or the ocean. The sediments are sorted by fluvial processes. They differ from glacial till, which is moved and deposited by the ice of the glacier, and is unsorted.

References

  1. "peninsula". The American Heritage Dictionary of the English Language (5th ed.). HarperCollins. Retrieved 2016-05-01.
  2. 1 2 Nadeau 2006, p. 5.
  3. 1 2 3 4 HMH 2004, p. 216.
  4. "Definition of peninsula". Cambridge Dictionaries Online. Cambridge University Press . Retrieved 1 May 2016.
  5. 1 2 3 Kersey, Paul (23 July 2021). "What is a Peninsula?". Infoplease. Retrieved 2022-04-30.
  6. 1 2 "list of peninsulas". Britannica. Retrieved 2022-04-30.
  7. 1 2 Society, National Geographic (2011-01-21). "peninsula". National Geographic Society. Retrieved 2022-04-30.
  8. Mis 2009, p. 20.
  9. Niz 2006, p. 19.
  10. Heos 2010, p. 15.
  11. Heos 2010, p. 9.
  12. Mis 2009, p. 6.
  13. Heos 2010, p. 8.
  14. 1 2 3 4 5 Heos 2010, p. 31.
  15. 1 2 Nadeau 2006, p. 6.
  16. Heos 2010, p. 32–33.
  17. Nadeau 2006, p. 9.
  18. Wyckoff 1999, p. 328.
  19. Heos 2010, p. 44.
  20. Heos 2010, p. 21–23.
  21. Nadeau 2006, p. 10.
  22. Heos 2010, pp. 43–44.
  23. Heos 2010, p. 40.
  24. Nadeau 2006, p. 13.
  25. Niz 2006, p. 7.
  26. Niz 2006, p. 13.
  27. Nadeau 2006, p. 21.
  28. 1 2 Heos 2010, p. 45.
  29. Heos 2010, p. 48.

Bibliography