A moraine is any accumulation of unconsolidated debris ( regolith and rock ), sometimes referred to as glacial till , that occurs in both currently and formerly glaciated regions, and that has been previously carried along by a glacier or ice sheet. It may consist of partly rounded particles ranging in size from boulders (in which case it is often referred to as boulder clay) down to gravel and sand, in a groundmass of finely-divided clayey material sometimes called glacial flour . Lateral moraines are those formed at the side of the ice flow, and terminal moraines are those formed at the foot, marking the maximum advance of the glacier. Other types of moraine include ground moraines ( till -covered areas forming sheets on flat or irregular topography ) and medial moraines (moraines formed where two glaciers meet).
30-527: Gutter Sound is a sound in the Orkney archipelago , Scotland, part of Scapa Flow . It lies to the west of the main harbour between the internal islands of Cava and Fara , and the large outer island of Hoy . Gutter Sound was one of the sites of the scuttling of the interned Imperial German High Seas Fleet in 1919, and the scene of a major salvage operation in the 1920s. The remaining wrecks are frequently visited by recreational divers. Gutter Sound
60-417: A long moraine bank marking the ice margin. Several processes may combine to form and rework a single moraine, and most moraines record a continuum of processes. Reworking of moraines may lead to the formation of placer deposits of gold as is the case of southernmost Chile . Moraines can be classified either by origin, location with respect to a glacier or former glacier, or by shape. The first approach
90-403: A smaller body of water usually connected to a sea or an ocean. A sound may be an inlet that is deeper than a bight and wider than a fjord ; or a narrow sea channel or an ocean channel between two land masses, such as a strait ; or also a lagoon between a barrier island and the mainland. A sound is often formed by the seas flooding a river valley . This produces a long inlet where
120-479: A sound that often has steep, near vertical sides that extend deep underwater. The sea floor is often flat and deeper at the landward end than the seaward end, due to glacial moraine deposits. This type of sound is more properly termed a fjord (or fiord). The sounds in Fiordland , New Zealand, have been formed this way. A sound generally connotes a protected anchorage. It can be part of most large islands. In
150-428: A terminal moraine. They form perpendicular to the lateral moraines that they reside between and are composed of unconsolidated debris deposited by the glacier. They are created during temporary halts in a glacier's retreat. In permafrost areas an advancing glacier may push up thick layers of frozen sediments at its front. An arctic push moraine will then be formed. A medial moraine is a ridge of moraine that runs down
180-638: Is derived from the Anglo-Saxon or Old Norse word sund , which also means " swimming ". The word sund is also documented in Old Norse and Old English as meaning "gap" (or "narrow access"). This suggests a relation to verbs meaning "to separate", such as absondern and aussondern ( German ), söndra ( Swedish ), sondre ( Norwegian ), as well as the English noun sin , German Sünde ("apart from God's law"), and Swedish synd . English has also
210-553: Is four miles long and a mile wide at its widest point, and has a depth of around 30 meters in places. It separates Hoy and Cava in the north, and Hoy and Fara in the south, opening onto Scapa Flow between Cava and Fara. In the north it opens out into the Bring Deeps, while the south it joins Weddell Sound, between Fara and Flotta , and to Switha Sound, between Flotta and Hoy. At the end of the First World War, Scapa Flow
240-450: Is suitable for moraines associated with contemporary glaciers—but more difficult to apply to old moraines , which are defined by their particular morphology, since their origin is debated. Some moraine types are known only from ancient glaciers, while medial moraines of valley glaciers are poorly preserved and difficult to distinguish after the retreat or melting of the glacier. Lateral moraines are parallel ridges of debris deposited along
270-659: Is the main waterway between the Baltic Sea and the North Sea . It is also a colloquial short name, among others, for Plymouth Sound , England . In areas explored by the British in the late 18th century, particularly the northwest coast of North America, the term "sound" was applied to inlets containing large islands, such as Howe Sound in British Columbia and Puget Sound in the U.S. state of Washington . It
300-467: The Baltic Sea, like Fehmarnsund , Strelasund , and Stralsund . Moraine The word moraine is borrowed from French moraine [mɔ.ʁɛn] , which in turn is derived from the Savoyard Italian morena ('mound of earth'). Morena in this case was derived from Provençal morre ('snout'), itself from Vulgar Latin * murrum ('rounded object'). The term
330-520: The Second World War the Sound was again used as a Royal Navy anchorage, being the site for HMS Proserpine , the stone frigate ashore base at Lyness ; it also served for the anti-submarine patrol forces and their depot ship, HMS Dunluce Castle . Commercial salvage work on the vessels ceased in the late 1970s and further salvage is no longer technically possible. Lyness is now
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#1732773229129360-530: The adjective "asunder" and the noun "sundry', and Swedish has the adjective sönder ("broken"). In Swedish and in both Norwegian languages , "sund" is the general term for any strait. In Danish, Swedish and Nynorsk , it is even part of names worldwide, such as in Swedish "Berings sund" and "Gibraltar sund", and in Nynorsk "Beringsundet" and "Gibraltarsundet". In German "Sund" is mainly used for place names in
390-603: The center of a valley floor. It forms when two glaciers meet and the debris on the edges of the adjacent valley sides join and are carried on top of the enlarged glacier. As the glacier melts or retreats, the debris is deposited and a ridge down the middle of the valley floor is created. The Kaskawulsh Glacier in the Kluane National Park , Yukon , has a ridge of medial moraine 1 km wide. Supraglacial moraines are created by debris accumulated on top of glacial ice. This debris can accumulate due to ice flow toward
420-676: The eastern shores of the Bronx , Westchester County , and southern Connecticut . Similarly, in North Carolina , a number of large lagoons lie between the mainland and its barrier beaches, the Outer Banks . These include Pamlico Sound , Albemarle Sound , Bogue Sound , and several others. The Mississippi Sound separates the Gulf of Mexico from the mainland, along much of the gulf coasts of Alabama and Mississippi . The term sound
450-511: The glacier has melted. Moraines may form through a number of processes, depending on the characteristics of sediment, the dynamics on the ice, and the location on the glacier in which the moraine is formed. Moraine forming processes may be loosely divided into passive and active . Passive processes involve the placing of chaotic supraglacial sediments onto the landscape with limited reworking, typically forming hummocky moraines. These moraines are composed of supraglacial sediments from
480-428: The glacier margin (up to 80 degrees) than further away (where slopes are typically 29 to 36 degrees. Ground moraines are till-covered areas with irregular topography and no ridges, often forming gently rolling hills or plains, with relief of less than 10 meters (33 ft). Ground moraine is accumulated at the base of the ice as lodgment till with a thin and discontinuous upper layer of supraglacial till deposited as
510-544: The glacier retreats. It typically is found in the areas between end moraines. Rogen moraines or ribbed moraines are a type of basal moraines that form a series of ribs perpendicular to the ice flow in an ice sheet . The depressions between the ribs are sometimes filled with water, making the Rogen moraines look like tigerstripes on aerial photographs . Rogen moraines are named after Lake Rogen in Härjedalen , Sweden ,
540-415: The ice surface. Active processes form or rework moraine sediment directly by the movement of ice, known as glaciotectonism. These form push moraines and thrust-block moraines, which are often composed of till and reworked proglacial sediment. Moraine may also form by the accumulation of sand and gravel deposits from glacial streams emanating from the ice margin. These fan deposits may coalesce to form
570-503: The landform's type locality. Closely related to Rogen moraines, de Geer moraines are till ridges up to 5m high and 10–50m wide running perpendicular to the ice flow. They occur in large groups in low-lying areas. Named for Gerard De Geer , who first described them in 1889, these moraines may have developed from crevasses underneath the ice sheet. The Kvarken has a very high density of de Geer moraines. End moraines, or terminal moraines , are ridges of unconsolidated debris deposited at
600-411: The moraine. There are two types of end moraines: terminal and recessional. Terminal moraines mark the maximum advance of the glacier. Recessional moraines are small ridges left as a glacier pauses during its retreat. After a glacier retreats, the end moraine may be destroyed by postglacial erosion. Recessional moraines are often observed as a series of transverse ridges running across a valley behind
630-541: The more general northern European usage, a sound is a strait or the narrowest part of a strait. In Scandinavia and around the Baltic Sea , there are more than a hundred straits named Sund , mostly named for the island they separate from the continent or a larger island. In contrast, the Sound is the common international short name for Øresund, the narrow stretch of water that separates Denmark and Sweden , and
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#1732773229129660-454: The sides of a glacier. The unconsolidated debris can be deposited on top of the glacier by frost shattering of the valley walls or from tributary streams flowing into the valley, or may be subglacial debris carried to the surface of the glacier, melted out, and transported to the glacier margin. Lateral moraines can rise up to 140 meters (460 ft) over the valley floor, can be up to 3 kilometers (1.9 mi) long, and are steeper close to
690-400: The site of a Naval Cemetery, and a Heritage Centre detailing these events. it is also the site of a dive centre, as the seven vessels that remain are a common target for divers . The seven remaining wrecks are often visited by scuba divers. In addition, debris and wreckage left from the ships salvaged is sometimes dived as well. Sound (geography) In geography , a sound is
720-459: The sloping valley hillsides descend to sea-level and continue beneath the water to form a sloping sea floor. These sounds are more appropriately called rias . The Marlborough Sounds in New Zealand are good examples of this type of formation. Sometimes a sound is produced by a glacier carving out a valley on a coast then receding, or the sea invading a glacier valley. The glacier produces
750-427: The snout or end of the glacier. They usually reflect the shape of the glacier's terminus . Glaciers act much like a conveyor belt, carrying debris from the top of the glacier to the bottom where it deposits it in end moraines. End moraine size and shape are determined by whether the glacier is advancing, receding or at equilibrium. The longer the terminus of the glacier stays in one place, the more debris accumulate in
780-438: The sunken ships were salvaged by Ernest Cox during the 1920s. He used a variety of techniques, lifting the smaller ships with floating dry docks and hawsers . With the larger ships he patched all of the holes and then pumped the hulls with compressed air to force out the water and make them float upside down. Seven of the wrecks are still at Scapa Flow, and are protected as maritime scheduled ancient monuments . During
810-419: The surface in the ablation zone , melting of surface ice or from debris that falls onto the glacier from valley sidewalls. Washboard moraines , also known as minor or corrugated moraines , are low-amplitude geomorphic features caused by glaciers. They consist of low-relief ridges, 1 to 2 meters (3 ft 3 in to 6 ft 7 in) in height and around 100 meters (330 ft) apart, accumulated at
840-694: Was also applied to bodies of open water not fully open to the ocean, such as Caamaño Sound or Queen Charlotte Sound in Canada; or broadenings or mergings at the openings of inlets, like Cross Sound in Alaska and Fitz Hugh Sound in British Columbia. Along the east coast and Gulf Coast of the United States, a number of bodies of water that separate islands from the mainland are called "sounds". Long Island Sound separates Long Island from
870-467: Was introduced into geology by Horace Bénédict de Saussure in 1779. Moraines are landforms composed of glacial till deposited primarily by glacial ice. Glacial till, in turn, is unstratified and unsorted debris ranging in size from silt -sized glacial flour to large boulders. The individual rock fragments are typically sub-angular to rounded in shape. Moraines may be found on the glacier's surface or deposited as piles or sheets of debris where
900-514: Was the anchorage for the surrendered German High Seas Fleet; these vessels were anchored around the island of Cava, in the Sound itself and in the Flow between Cava and the Barrel of Butter skerry. In 1919 this was the scene of the fleet's mass scuttling . 12 capital ships and a number of smaller vessels went down in the Sound itself, the remainder in deep water between Cava and the skerry. A number of
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