A peninsula is a landform that extends from a mainland and is surrounded by water on most sides. Peninsulas exist on each continent. The largest peninsula in the world is the Arabian Peninsula .
18-759: Inderøya is a peninsula in the Trondheimsfjord in Trøndelag county, Norway . The peninsula constitutes the northern (more populated) part of the municipality of Inderøy (which is named after the peninsula). The peninsula borders the Beitstadfjorden to the north, the Børgin fjord to the east, the Skarnsund strait to the west, and the Trondheimsfjord to the south. It is connected to
36-469: A basin . This may create peninsulas, and occurred for example in the Keweenaw Peninsula . In the case of formation from meltwater, melting glaciers deposit sediment and form moraines , which act as dams for the meltwater. This may create bodies of water that surround the land, forming peninsulas. If deposition formed the peninsula, the peninsula was composed of sedimentary rock , which
54-433: A constructive boundary or an extensional boundary ) is a linear feature that exists between two tectonic plates that are moving away from each other. Divergent boundaries within continents initially produce rifts , which eventually become rift valleys . Most active divergent plate boundaries occur between oceanic plates and exist as mid-oceanic ridges . Current research indicates that complex convection within
72-402: A major source of submarine earthquakes . A seafloor map will show a rather strange pattern of blocky structures that are separated by linear features perpendicular to the ridge axis. If one views the seafloor between the fracture zones as conveyor belts carrying the ridge on each side of the rift away from the spreading center the action becomes clear. Crest depths of the old ridges, parallel to
90-493: Is sometimes thought to be associated with the phenomenon known as hotspots . Here, exceedingly large convective cells bring very large quantities of hot asthenospheric material near the surface, and the kinetic energy is thought to be sufficient to break apart the lithosphere. Divergent boundaries are typified in the oceanic lithosphere by the rifts of the oceanic ridge system, including the Mid-Atlantic Ridge and
108-487: The Earth's mantle allows material to rise to the base of the lithosphere beneath each divergent plate boundary. This supplies the area with huge amounts of heat and a reduction in pressure that melts rock from the asthenosphere (or upper mantle ) beneath the rift area, forming large flood basalt or lava flows. Each eruption occurs in only a part of the plate boundary at any one time, but when it does occur, it fills in
126-472: The East Pacific Rise , and in the continental lithosphere by rift valleys such as the famous East African Great Rift Valley . Divergent boundaries can create massive fault zones in the oceanic ridge system. Spreading is generally not uniform, so where spreading rates of adjacent ridge blocks are different, massive transform faults occur. These are the fracture zones , many bearing names, that are
144-572: The 16th century. A peninsula is generally defined as a piece of land surrounded on most sides by water. 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. 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. A peninsula may be connected to
162-499: The case of Florida , continental drift, marine sediment, and marine transgressions were all contributing factors to its shape. In the case of formation from glaciers (e.g., the Antarctic Peninsula or Cape Cod ), peninsulas can be created due to glacial erosion , meltwater or deposition . If erosion formed the peninsula, softer and harder rocks were present, and since the glacier only erodes softer rock, it formed
180-418: The current spreading center, will be older and deeper... (from thermal contraction and subsidence ). It is at mid-ocean ridges that one of the key pieces of evidence forcing acceptance of the seafloor spreading hypothesis was found. Airborne geomagnetic surveys showed a strange pattern of symmetrical magnetic reversals on opposite sides of ridge centers. The pattern was far too regular to be coincidental as
198-599: The mainland via a narrow strip of land to the northeast. Until 2011, the municipality of Inderøy covered the peninsula in addition to the Røra area, but since 2012, Inderøy has also included Mosvik , a larger peninsula on the west side of Skarnsund. This Trøndelag location article is a stub . You can help Misplaced Pages by expanding it . Peninsula The word peninsula derives from Latin paeninsula , from paene 'almost' and insula 'island'. The word entered English in
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#1732791466618216-531: The mainland via an isthmus , for example, in the Isthmus of Corinth which connects to the Peloponnese peninsula. Peninsulas can be formed from continental drift , glacial erosion , glacial meltwater , glacial deposition , marine sediment , marine transgressions , volcanoes, divergent boundaries or river sedimentation. More than one factor may play into the formation of a peninsula. For example, in
234-538: The opening gap as the two opposing plates move away from each other. Over millions of years, tectonic plates may move many hundreds of kilometers away from both sides of a divergent plate boundary. Because of this, rocks closest to a boundary are younger than rocks further away on the same plate. At divergent boundaries, two plates move away from each other and the space that this creates is filled with new crustal material sourced from molten magma that forms below. The origin of new divergent boundaries at triple junctions
252-468: The sediment is deposited, forming a delta peninsula. 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. Similarly, wet weather causing higher water levels make peninsulas appear smaller, while dry weather make them appear larger. Sea level rise from global warming will permanently reduce
270-432: The size of some peninsulas over time. Peninsulas are noted for their use as shelter for humans and Neanderthals . The landform is advantageous because it gives hunting access to both land and sea animals. They can also serve as markers of a nation's borders. Divergent boundary This is an accepted version of this page In plate tectonics , a divergent boundary or divergent plate boundary (also known as
288-564: The volcano erupts near shallow water. Marine sediment may form peninsulas by the creation of limestone . A rift peninsula may form as a result of a divergent boundary in plate tectonics (e.g. the Arabian Peninsula ), while a convergent boundary may also form peninsulas (e.g. Gibraltar or the Indian subcontinent ). Peninsulas can also form due to sedimentation in rivers. When a river carrying sediment flows into an ocean,
306-530: The widths of the opposing bands were too closely matched. Scientists had been studying polar reversals and the link was made by Lawrence W. Morley , Frederick John Vine and Drummond Hoyle Matthews in the Morley–Vine–Matthews hypothesis . The magnetic banding directly corresponds with the Earth's polar reversals. This was confirmed by measuring the ages of the rocks within each band. The banding furnishes
324-504: Was created from a large deposit of glacial drift . 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. In the case of formation from volcanoes, when a volcano erupts magma near water, it may form a peninsula (e.g., the Alaskan Peninsula ). Peninsulas formed from volcanoes are especially common when
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