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27-505: The following notable features of Cook Bay were named by DI personnel, unless otherwise noted. Cape Crewe forms the north side of the entrance to Cook Bay. Cape Crewe is an established name, dating back to about 1912. Crewe Rock, an offshore rock about 3 metres (10 ft) high, lies 0.1 nautical miles (0.2 km) east of Cape Crewe, for which it is named. Kelp Bank is a shoal , covered with kelp , lying 2 nautical miles (4 km) northeast of Cape Crewe. The name appears to be first used on

54-445: A beach , the term shoal can be applied to larger geological units that form off a coastline as part of the process of coastal erosion, such as spits and baymouth bars that form across the front of embayments and rias . A tombolo is a bar that forms an isthmus between an island or offshore rock and a mainland shore. In places of reentrance along a coastline (such as inlets , coves , rias, and bays), sediments carried by

81-451: A body of water close to the surface or above it, which poses a danger to navigation. Shoals are also known as sandbanks , sandbars , or gravelbars . Two or more shoals that are either separated by shared troughs or interconnected by past or present sedimentary and hydrographic processes are referred to as a shoal complex . The term shoal is also used in a number of ways that can be either similar to, or quite different from, how it

108-401: A harbor entrance or river mouth by the deposition of freshwater sediment or by the action of waves on the sea floor or on up-current beaches. Where beaches are suitably mobile, or the river's suspended or bed loads are large enough, deposition can build up a sandbar that completely blocks a river mouth and dams the river. It can be a seasonally natural process of aquatic ecology , causing

135-433: A longshore current will fall out where the current dissipates, forming a spit. An area of water isolated behind a large bar is called a lagoon. Over time, lagoons may silt up, becoming salt marshes . In some cases, shoals may be precursors to beach expansion and dunes formation, providing a source of windblown sediment to augment such beach or dunes landforms. Since prehistoric times, humans have chosen some shoals as

162-470: A 1931 British Admiralty chart. A small rock group referred to as the Olav Rocks lies 0.6 nmi (1.1 km) east-southeast of Cape Crewe. It was named because the rocks serve as a guide to vessels entering Prince Olav Harbor . DI charts recorded the incorrect spelling, "Prince Olaf Rocks," but later charts corrected this error, and the shortened form of the original name is approved. Lighthouse Bay forms

189-413: A greater to a lesser depth of water. Shoals are characteristically long and narrow (linear) ridges. They can develop where a stream , river , or ocean current promotes deposition of sediment and granular material , resulting in localized shallowing (shoaling) of the water. Marine shoals also develop either by the in-place drowning of barrier islands as the result of episodic sea level rise or by

216-412: A length of a few meters in a small stream to marine depositions stretching for hundreds of kilometers along a coastline, often called barrier islands . They are typically composed of sand , although they could be of any granular matter that the moving water has access to and is capable of shifting around (for example, soil , silt , gravel , cobble , shingle , or even boulders ). The grain size of

243-527: A site of habitation. In some early cases, the locations provided easy access to exploit marine resources. In modern times, these sites are sometimes chosen for the water amenity or view, but many such locations are prone to storm damage. An area in Northwest Alabama is commonly referred to as “ The Shoals ” by local inhabitants, and one of the cities, Muscle Shoals , is named for such landform and its abundance of Mussels . Landform A landform

270-427: A sloping bank which is shallower at one end than the other, then the shoaling effect will result in the waves slowing more at the shallow end. Thus, the wave fronts will refract, changing direction like light passing through a prism. Refraction also occurs as waves move towards a beach if the waves come in at an angle to the beach, or if the beach slopes more gradually at one end than the other. Sandbars, also known as

297-430: A trough bars, form where the waves are breaking, because the breaking waves set up a shoreward current with a compensating counter-current along the bottom. Sometimes this occurs seaward of a trough (marine landform). Sand carried by the offshore moving bottom current is deposited where the current reaches the wave break. Other longshore bars may lie further offshore, representing the break point of even larger waves, or

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324-439: Is a navigation or grounding hazard, with a depth of water of 6 fathoms (11 meters) or less. It therefore applies to a silt accumulation that shallows the entrance to or course of a river, or creek. A bar can form a dangerous obstacle to shipping, preventing access to the river or harbor in poor weather conditions or at some states of the tide . In addition to longshore bars discussed above that are relatively small features of

351-485: Is a natural or anthropogenic land feature on the solid surface of the Earth or other planetary body . Landforms together make up a given terrain , and their arrangement in the landscape is known as topography . Landforms include hills , mountains , canyons , and valleys , as well as shoreline features such as bays , peninsulas , and seas , including submerged features such as mid-ocean ridges , volcanoes , and

378-427: Is called shoaling , and the waves are said to shoal. The waves may or may not build to the point where they break , depending on how large they were to begin with, and how steep the slope of the beach is. In particular, waves shoal as they pass over submerged sandbanks or reefs. This can be treacherous for boats and ships. Shoaling can also refract waves, so the waves change direction. For example, if waves pass over

405-425: Is the third or vertical dimension of land surface . Topography is the study of terrain, although the word is often used as a synonym for relief itself. When relief is described underwater , the term bathymetry is used. In cartography , many different techniques are used to describe relief, including contour lines and triangulated irregular networks . Elementary landforms (segments, facets, relief units) are

432-399: Is used in geologic, geomorphic, and oceanographic literature. Sometimes, the term refers to either any relatively shallow place in a stream , lake , sea , or other body of water; a rocky area on the seafloor within an area mapped for navigation purposes; or, a growth of vegetation on the bottom of a deep lake, that occurs at any depth, or is used as a verb for the process of proceeding from

459-538: The United States Geological Survey . This South Georgia and the South Sandwich Islands location article is a stub . You can help Misplaced Pages by expanding it . Shoal In oceanography , geomorphology , and geoscience , a shoal is a natural submerged ridge , bank , or bar that consists of, or is covered by, sand or other unconsolidated material, and rises from the bed of

486-504: The Universe . Examples are mountains, hills, polar caps, and valleys, which are found on all of the terrestrial planets . The scientific study of landforms is known as geomorphology . In onomastic terminology, toponyms (geographical proper names) of individual landform objects (mountains, hills, valleys, etc.) are called oronyms . Landforms may be extracted from a digital elevation model (DEM) using some automated techniques where

513-400: The break point at low tide. In Russian tradition of geomorphology , a peresyp is a sandbar that rises above the water level (like a spit ) and separates a liman or a lagoon from the sea. Unlike tombolo bars, a peresyp seldom forms a contiguous strip and usually has one or several channels that connect the liman and the sea. A harbor or river bar is a sedimentary deposit formed at

540-407: The erosion and submergence of inactive delta lobes . Shoals can appear as a coastal landform in the sea , where they are classified as a type of ocean bank , or as fluvial landforms in rivers, streams, and lakes . A shoal–sandbar may seasonally separate a smaller body of water from the sea, such as: The term bar can apply to landform features spanning a considerable range in size, from

567-422: The formation of estuaries and wetlands in the lower course of the river. This situation will persist until the bar is eroded by the sea, or the dammed river develops sufficient head to break through the bar. The formation of harbor bars that prevent access for boats and shipping can be the result of: In a nautical sense, a bar is a shoal, similar to a reef : a shallow formation of (usually) sand that

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594-591: The four major types of landforms. Minor landforms include buttes , canyons, valleys, and basins. Tectonic plate movement under the Earth can create landforms by pushing up mountains and hills. Oceans and continents exemplify the highest-order landforms. Landform elements are parts of a high-order landforms that can be further identified and systematically given a cohesive definition such as hill-tops, shoulders, saddles , foreslopes and backslopes. Some generic landform elements including: pits, peaks, channels, ridges, passes, pools and plains. Terrain (or relief )

621-596: The great ocean basins . Landforms are categorized by characteristic physical attributes such as elevation, slope, orientation, structure stratification , rock exposure, and soil type. Gross physical features or landforms include intuitive elements such as berms , mounds , hills , ridges , cliffs , valleys , rivers , peninsulas , volcanoes , and numerous other structural and size-scaled (e.g. ponds vs. lakes , hills vs. mountains ) elements including various kinds of inland and oceanic waterbodies and sub-surface features. Mountains, hills, plateaux , and plains are

648-408: The material comprising a bar is related to the size of the waves or the strength of the currents moving the material, but the availability of material to be worked by waves and currents is also important. Wave shoaling is the process when surface waves move towards shallow water, such as a beach, they slow down, their wave height increases and the distance between waves decreases. This behavior

675-574: The northern arm of Cook Bay between Cape Crewe and Point Abrahamsen. It was probably named for the now-disused lighthouse on Sheep Point to the south. South of Lighthouse Bay, Prince Olav Harbour makes up the majority of Cook Bay. Further south, a narrow strait called Carl Passage, 0.2 nautical miles (0.4 km) long, connects Elephant Lagoon, which is about 0.3 nautical miles (0.6 km) long, to Cook Bay. "Carl Passage" may reflect an earlier naming. [REDACTED]  This article incorporates public domain material from websites or documents of

702-492: The role of vegetation in the development of dune systems and salt marshes , and the work of corals and algae in the formation of coral reefs . Landforms do not include several man-made features, such as canals , ports and many harbors ; and geographic features, such as deserts , forests , and grasslands . Many of the terms are not restricted to refer to features of the planet Earth , and can be used to describe surface features of other planets and similar objects in

729-644: The smallest homogeneous divisions of the land surface, at the given scale/resolution. These are areas with relatively homogeneous morphometric properties, bounded by lines of discontinuity. A plateau or a hill can be observed at various scales, ranging from a few hundred meters to hundreds of kilometers. Hence, the spatial distribution of landforms is often scale-dependent, as is the case for soils and geological strata. A number of factors, ranging from plate tectonics to erosion and deposition (also due to human activity), can generate and affect landforms. Biological factors can also influence landforms—for example, note

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