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38-546: The Outer Lands is the prominent terminal moraine archipelagic region off the southern coast of New England in the United States. This eight-county region of Massachusetts , Rhode Island , and New York comprises the peninsula of Cape Cod and the islands of Nantucket , Martha's Vineyard , the Elizabeth Islands , Block Island , and Long Island , as well as surrounding islands and islets. Though

76-409: 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

114-417: 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

152-762: A process where the accumulation of snow , in the zone of accumulation is greater than loss due to melting or ablation. During the Last Glacial Maximum (LGM), the Northern hemisphere began its modern ice-age. Most of what is now Canada and northern portions of the United States were covered in ice sheets or mountain driven glaciers during the last stage of the Pleistocene Epoch . In the last 400,000 years there have been roughly four major glacial events. Evidence of these separate events

190-438: A strong maritime culture, with an emphasis on fishing. From eastern Long Island east, much of the region has in recent decades taken on a summer colony character. Terminal moraine A terminal moraine , also called an 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

228-416: A structure that appears to be a barrier for water, there are still ways for the water to flow through. Water makes its way through glacial till to form streams and channels . Another landscape feature formed by terminal moraines are kettle lakes . These are produced during glacial recession when boulders or blocks of ice are left in place as the glacier recedes from the newly deposited terminal moraine. As

266-428: 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

304-450: Is deposited to form a new terminal moraine. The more debris that is found within the ice, the longer it will take for complete melting to occur. Climate plays an important role in the formation of terminal moraines. As temperatures increase, glaciers begin to retreat faster, causing more glacial till to be deposited in the form of terminal moraines. However, when temperatures decrease, zone of accumulation goes into overdrive. This starts

342-573: Is found not only in ice cores , but also in the glacial till that was deposited. Rocks and sediment not native to one area could be found in a region completely foreign to that from which they were formed. This is the result of a prior terminal moraine being picked up and deposited by a newer glacial event. The terminal moraines resulting from the Last Glacial Maximum are the most informational features about glacial advance still present today. During glacial retreat, meltwater flows in

380-539: Is instead part of the Manhattan Prong . The islands are separated from the mainland by a series of bays and sounds that used to make up Lake Connecticut , Lake Narragansett , and other glacial lakes. For eastern Long Island and areas east, the region is designated Environmental Protection Agency ecoregion 84 for the Atlantic coastal pine barrens , with the majority 84a for "Cape Cod/Long Island", and along

418-538: Is often informally considered a part of the "New York islands" alongside Staten Island and Manhattan . These islands are geographically contiguous with the broader region. (The insular Massachusetts sections were actually part of the Province of New York for most of the late 17th century.) Other islands in Long Island Sound and Rhode Island Sound ( Narragansett Bay Islands ) are also often included in

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456-450: 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

494-778: The Forno Glacier in the south-eastern canton of Graubünden near St. Moritz and the Italian border. In New Zealand the Franz Josef Glacier on the West Coast has created the terminal moraine called the Waiho Loop . Moraine 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

532-538: The Outer Lands is a name given to the terminal moraine archipelago of the northeastern region of the United States ( Cape Cod , Martha's Vineyard , Nantucket , Block Island and Long Island ). According to geologist George Frederick Wright some of the most prominent examples of terminal moraines on Long Island are "the most remarkable in the world". Other prominent examples of terminal moraines are

570-606: The Tinley Moraine and the Valparaiso Moraine , perhaps the best examples of terminal moraines in North America. These moraines are most clearly seen southwest of Chicago. In Europe , virtually all the terrain in the central Netherlands is made up of an extended terminal moraine. In Switzerland , alpine terminal moraines can be found, one striking example being the moraine at the end of the valley of

608-506: The meltwater . Here, old vegetation is buried by the sediment, but new vegetation can still survive relatively well as long as it can acquire meltwater from the now receding glacier. Terminal moraines are one of the most prominent types of moraines in the Arctic . One notable terminal moraine is Trollgarden in Norway , once thought to be magically constructed by trolls . In North America,

646-583: The Long Island south shore 84c for " Barrier Islands /Coastal Marshes". Western Long Island and along the north shore is largely 59g for " Long Island Sound Coastal Lowland", a part of the broader Northeastern Coastal Zone. The region is designated the "Long Island-Cape Cod Coastal Lowland", Major Land Resource Area 149B, by the United States Department of Agriculture, which also includes Staten Island. The region has historically had

684-603: 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

722-401: The existence of an arc or chain of islands in this archipelago is widely acknowledged by geographers, it is rarely given a specific name; occasionally a descriptive term such as southern New England islands or a technical term such as Cape Cod/Long Island ecoregion or Long Island–Cape Cod Coastal Lowland is used. The Isles of Stirling was the name granted in 1635 when the islands came into

760-508: 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. As a glacier moves along its path, the surrounding area is continuously eroding. Loose rock and pieces of bedrock are constantly being picked up and transported with

798-511: 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

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836-428: 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

874-544: 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 ,

912-530: The glacier. Fine sediment and particles are also incorporated into the glacial ice. The accumulation of these rocks and sediment together form what is called glacial till when deposited. Push moraines are formed when a glacier retreats from a previously deposited terminal moraine, only to push proglacial sediment or till into an existing terminal moraine. This process can make the existing terminal moraine far larger than its previous size. Dump moraines occur when rock, sediment, and debris, which accumulate at

950-578: 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). 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

988-473: The ice boulders melt, they begin to pool to form kettle lakes in the glacial outwash plain . The terminal moraine is the furthest point of disturbed sediment, which is formed into a long mound outlining the front edge of the glacier. This mound typically consists of a large quantity of rocks and boulders along with sediment, and can combine to reach a height of multiple meters. The process of uplifting and moving these large rocks and boulders negatively affects

1026-415: 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

1064-503: 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

1102-413: The local vegetation by either crushing them or contributing to the process of the glacier plowing the topsoil , which removes the vegetation from the soil completely, including the root systems . In this area of disturbed land, it is difficult for new vegetation to grow. Immediately beyond the terminal moraine is the glacial outwash plain , covered in a layer of sediment, with braided streams formed from

1140-411: 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

1178-428: The opposite direction of the retreat, causing braided streams and channels to form. A terminal moraine creates a barrier helping to trap water in a newly-formed glacial lake . The positioning of the lake resulted from not only subsidence , but also the terminal moraine providing the foundation for the wall that holds the water in place. While the terminal moraine consists of a long mound of rock and sediment which forms

Outer Lands - Misplaced Pages Continue

1216-533: The possession of William Alexander, 1st Earl of Stirling . "Outer Lands" is a term popularized by author Dorothy Sterling in her 1967 natural history guide of the same name, and used by later natural history authors such as Patrick J. Lynch . The Massachusetts section is often called the "Cape and Islands", with the "Islands" subregion very specifically referring to Martha's Vineyard, Nantucket and other smaller islands in Dukes and Nantucket counties. Long Island

1254-738: The region. More rarely, Sandy Hook in New Jersey is included. The Outer Lands forms the insular northeasternmost extension of North America's Atlantic coastal plain . The islands of the Outer Lands were formed of terminal moraines deposited on a series of cuestas by the recession of the Laurentide Ice Sheet during the Wisconsin glaciation . Some of the islands are included in the archipelago due to proximity, despite key geological differences, such as Manhattan , which

1292-454: 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

1330-427: 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

1368-419: 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

1406-405: The top surface of the glacier, either slide, fall, or flow off of the snout of the glacier. The accumulation of till will form a terminal moraine as the glacier retreats. Ablation moraines form when a large piece of ice, containing an accumulation of sediment and debris, breaks from the snout of the glacial. Once it is separated and begins to melt, the debris found throughout this glacial piece

1444-467: 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

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