Tombolos demonstrate the sensitivity of shorelines. A small piece of land, such as an island, or a beached shipwreck can change the way that waves move, leading to different deposition of sediments. Sea level rise may also contribute to accretion, as material is pushed up with rising sea levels. Tombolos are more prone to natural fluctuations of profile and area as a result of tidal and weather events than a normal beach is.
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Normally, tombolos are created due to the effects of the island on waves (through refraction) and to sediment transport, which usually produces a beach perpendicular to the mainland rather than parallel to it.
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The bay shores are typically steep, reflective beaches composed of very coarse sand to granules eroded from adjacent cliffs and alluvial deposits. Wide pocket beaches and tombolos are common along sectors with abundant rocky erosional remnants and stacks.
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Several islands tied together by bars which rise above the water level are called a tombolo cluster.Glossary of Geology and Related Sciences. The American Geological Institute, 1957 Two or more tombolos may form an enclosure (called a lagoon) that can eventually fill with sediment.
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It is separated from the Tyrrhenian Sea by two tombolos (Giannella in the north and Feniglia in the south) that join the promontory of Monte Argentario to continental territory. In the middle of the lagoon, on another land strip, is located the town of Orbetello.
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It also appears in the English place name Skegness - 'beard point', from the way in which a series of tombolos forms, towards the nearby Gibraltar Point. Here, the English pronunciation reflects a probable Danish origin, which pronounces the sk letter combination as an English speaker would expect.
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True tombolos are formed by wave refraction and diffraction. As waves near an island, they are slowed by the shallow water surrounding it. These waves then bend around the island to the opposite side as they approach. The wave pattern created by this water movement causes a convergence of longshore drift on the opposite side of the island.
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Shoreline lakes are generally lakes created by blockage of estuaries or by the uneven accretion of beach ridges by longshore and other currents. They include maritime coastal lakes, ordinarily in drowned estuaries; lakes enclosed by two tombolos or spits connecting an island to the mainland; lakes cut off from larger lakes by a bar; or lakes divided by the meeting of two spits.
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Because of this susceptibility to weathering, tombolos are sometimes made more sturdy through the construction of roads or parking lots. The sediments that make up a tombolo are coarser towards the bottom and finer towards the surface. It is easy to see this pattern when the waves are destructive and wash away finer grained material at the top, revealing coarser sands and cobbles as the base.
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Firths are similar to fjords, but are generally shallower with broader bays in which small islands may be found. The glaciers that formed them influenced the land over a wider area and scraped away larger areas. Firths are to be found mostly on the Scottish and northern English coasts. Individual islands in the firths, or islands and the coast, are often joined up by sandbars or spits made up of sand deposits known as "tombolos".
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In the 1950s, in an effort to combat erosion, the state and federal governments built sets of concrete seawalls and perpendicular groins. In 1992, a series of 58 breakwaters were also constructed to help capture sand and significantly slowed its movement eastward. Even with the substantial engineering projects, sand has to be relocated from tombolos that form behind the breakwaters, and new sand has to be brought in annually to replenish the beaches.
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The island is a series of gravel bars (tombolos) connecting volcanic bedrock islands. The volcanism is not recent and may be millions of years old. The crescent shaped island may be the result of an eroded caldera similar to the much more recent Deception Island volcano complex. The parallel gravel bars are a result of post-glacial (isostatic) uplift of the area after the much larger Pleistocene ice cap melted and the pressure was released.
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It is in the parish of Delting. To the north west of Samphrey is Bunglan, which was once an island in its own right, but has become silted up by two tombolos, which now connect it to Samphrey. There is a small loch between Bunglan and Samphrey proper, which can just about be seen on the aerial picture. Blaeu's Atlas Maior calls the island "Sancterre" (Holy Land) in the 17th century, lending the island another intriguing etymology.
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Clearly discernible tombolos, spits, and barrier beaches are present at this former coastline, below present lake water levels. To the east, the present deep section of the bay east of the McPhee Islands was also a small lake, separated from the other lakes by a section of dry land, connected by a stream. Late Holocene subsidence resulted in a renewed influx of marine water in the last 4,500 years. The effects of this subsidence are seen in the transgressive character of many of the shoreline features.
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Coastal barriers are landscape features that protect the mainland, lagoons, wetlands and salt marshes from the full force of wind, wave and tidal energy. “Undeveloped coastal barriers” are defined by the CBRA to include barrier islands, bars, spits, and tombolos, along with associated aquatic habitats, such as adjacent estuaries and wetlands. Composed of sand and other loose sediments, these elongated, narrow landforms are dynamic ecosystems and are vulnerable to hurricane damage and shoreline recession. Coastal barriers also provide important habitat for a variety of wildlife, and are an important recreational resource.
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Churchill Barrier number 4 in Orkney used a shingle spit, the Ayre of Cara on South Ronaldsay, as its southern landfall. This ayre is still named on maps, despite having all but vanished under the causeway and the sand dunes that have accumulated on its eastern side. The term "ayre" is sometimes wrongly applied to sand tombolos (e.g. St. Ninian's tombolo in Shetland) and to the lakes and lagoons impounded by bay-head bars, which are more properly called British Regional Geology: Orkney and Shetland - Institute of Geological Sciences, 1976 in Orkney and in Shetland.
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The island is characterized by an irregular coastline of approximately , with numerous bays and inlets and a significant diversity of other coastal land forms, including spits, bluffs, dunes, lagoons, cuspate forelands, tombolos, tide flats, streams and tidal deltas, islands, and rocky outcrops. The high point is Toe Jam Hill. On the Kitsap Peninsula, Bremerton and Poulsbo lie across the Port Orchard channel to the west, and the city of Port Orchard lies across Rich Passage to the south. The island is quite hilly and is known for its popular Chilly Hilly bicycle ride every February.
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Green Hill near Cohasset and all of the hills out along the peninsula—Sagamore, Hampton, Sunset Point, Strawberry, Allerton, Telegraph, and Hull Hill—are drumlins formed by the last glacier about 14,000 years ago. The lands between the hills are tombolos, or tying sand bars. Telegraph Hill above Stony Beach is the site of Fort Revere Park, located at the site of a former defense installation that was active during the first half of the twentieth century. It is capped with an observation tower, which provides views of the rest of Boston Harbor, as well as much of the northern coast of the South Shore.
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This is the former settlement of Bouster, whose name suggests a Norse origin The Ness of Sound, one of many headlands connected by a tombolo In addition to these large indentations, there are a number of tombolos connecting peninsulas to the island. Many of these are very fragile, and can be damaged extremely easily by human erosion, or severe storms, creating new islands - or resurrecting old ones. There is comparatively little farmland, but the coast is conducive to fishing. Much of the interior of Yell is covered in a peat blanket, often as much as thick, which is the result of 3,000 years of deposits.
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Via Cassia became the most important road in medieval times, because it connected Rome with Viterbo, Siena, and Florence. The other main road to Rome, the Via Aurelia, became unsafe in medieval times with the spread of malaria, because it passed through the unhealthy marshes near several coastal lakes in the Maremma lowlands (as Orbetello lagoon, Capalbio lake, and other Tombolos), and because its route by the sea made it more susceptible to attack from raiders. The coastal towns around Via Aurelia were areas subjected to kidnapping of women and plunder by Muslim Saracen pirates. Because of the increasing importance of the area, several popes decided to improve its conditions.
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Retrieved 11 Nov 2011 Previously used for logging, farming, and mining during the early 20th century, the islands are returning to a primitive state; evidence of human habitation is still present, albeit mostly obscured by the regenerating forests. The islands' coastlines possess varied geology, where precambrian sandstone has eroded into sea caves, and the resulting sand has formed sandspits, cuspate forelands, tombolos, barrier spits, and beaches. Ecologically, the islands contain some old growth, but primarily secondary Northern hardwood forest. There are elements of the oak, hickory, and hemlock hardwood forests of the eastern United States, but also features of the Boreal forest typical of Ontario.
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Yell by the Ayre of Galtigarth – a tombolo that separates the tidal Loch of Galtigarth (on the right) from the open sea An ayre is the name used for shingle beaches in Orkney and Shetland.British Regional Geology: Orkney and Shetland - Institute of Geological Sciences, 1976The Shetland Dictionary - John J Graham, 1999 The word is derived from the Old Norse eyrr, meaning a shingle beach or gravelly place,The Dialect and Place Names of Shetland - Jakob Jakobsen, 1897 and may be applied to ordinary beaches, cliff-foot beaches such as the Lang AyreLang Ayre in Northmavine, Shetland, spits, bars or tombolos, but only if formed of shingle. More than 130 such shingle beaches are named on Ordnance Survey maps of Shetland, but far fewer in Orkney, where most beaches are formed of sand. The word in its Old Norse form is common in Iceland, and it also occurs in a few place names in the north and west of the Scottish mainland which had a strong Norse influence, such as Eriboll ("a homestead on a shingle beach").
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