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67-571: The formation was deposited in the Bearpaw Sea, which was part of the Western Interior Seaway that advanced and then retreated across the region during Campanian time. It is composed primarily of dark grey shales , claystones , silty claystones and siltstones , with subordinate silty sandstones . It also includes bedded and nodular concretions (both calcareous and ironstone concretions) and thin beds of bentonite . As

134-747: A number of continental shelves , including the Canadian Arctic shelf, underlying the Canadian Arctic Archipelago , and the Russian continental shelf , which is sometimes called the "Arctic Shelf" because it is larger. The Russian continental shelf consists of three separate, smaller shelves: the Barents Shelf, Chukchi Sea Shelf and Siberian Shelf . Of these three, the Siberian Shelf is the largest such shelf in

201-430: A pearly luster. Arctic Ocean Main five oceans division: Further subdivision: The Arctic Ocean is the smallest and shallowest of the world's five oceanic divisions . It spans an area of approximately 14,060,000 km (5,430,000 sq mi) and is the coldest of the world's oceans. The International Hydrographic Organization (IHO) recognizes it as an ocean, although some oceanographers call it

268-716: Is Molloy Hole in the Fram Strait , at about 5,550 m (18,210 ft). The two major basins are further subdivided by ridges into the Canada Basin (between Beaufort Shelf of North America and the Alpha Ridge ), Makarov Basin (between the Alpha and Lomonosov Ridges), Amundsen Basin (between Lomonosov and Gakkel ridges), and Nansen Basin (between the Gakkel Ridge and the continental shelf that includes

335-466: Is Monument Rocks , an exposed chalk formation towering 70 feet (21 m) over the surrounding range land. The Western Interior Seaway is believed to have behaved similarly to a giant estuary in terms of water mass transport. Riverine inputs exited the seaway as coastal jets, while correspondingly drawing in water from the Tethys in the south and Boreal waters from the north. During the late Cretaceous,

402-414: Is a section referred to as the sub-surface layer. It is a product of Atlantic water that enters through canyons and is subjected to intense mixing on the Siberian Shelf. As it is entrained, it cools and acts a heat shield for the surface layer on account of weak mixing between layers. However, over the past couple of decades a combination of the warming and the shoaling of Atlantic water are leading to

469-477: Is cloudy year-round, with mean cloud cover ranging from 60% in winter to over 80% in summer. The temperature of the surface water of the Arctic Ocean is fairly constant at approximately −1.8 °C (28.8 °F), near the freezing point of seawater . The density of sea water, in contrast to fresh water, increases as it nears the freezing point and thus it tends to sink. It is generally necessary that

536-565: Is contained in a polar climate characterized by persistent cold and relatively narrow annual temperature ranges. Winters are characterized by the polar night , extreme cold, frequent low-level temperature inversions, and stable weather conditions. Cyclones are only common on the Atlantic side. Summers are characterized by continuous daylight ( midnight sun ), and air temperatures can rise slightly above 0 °C (32 °F). Cyclones are more frequent in summer and may bring rain or snow. It

603-677: Is predominantly cyclonic on the Eurasian side and anticyclonic in the Canadian Basin . Water enters from both the Pacific and Atlantic Oceans and can be divided into three unique water masses. The deepest water mass is called Arctic Bottom Water and begins around 900 m (3,000 ft) depth. It is composed of the densest water in the World Ocean and has two main sources: Arctic shelf water and Greenland Sea Deep Water. Water in

670-495: Is the highest volumetric inflow to the Arctic Ocean, equalling about 10 times that of the Pacific inflow, and it creates the Arctic Ocean Boundary Current. It flows slowly, at about 0.02 m/s. Atlantic Water has the same salinity as Arctic Bottom Water but is much warmer (up to 3 °C [37 °F]). In fact, this water mass is actually warmer than the surface water and remains submerged only due to

737-687: The Arctic Mediterranean Sea . It has also been described as an estuary of the Atlantic Ocean . It is also seen as the northernmost part of the all-encompassing world ocean . The Arctic Ocean includes the North Pole region in the middle of the Northern Hemisphere and extends south to about 60°N . The Arctic Ocean is surrounded by Eurasia and North America, and the borders follow topographic features:

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804-527: The Arctic Ocean . The two land masses it created were Laramidia to the west and Appalachia to the east. At its largest extent, it was 2,500 feet (760 m) deep, 600 miles (970 km) wide and over 2,000 miles (3,200 km) long. By the late Cretaceous, Eurasia and the Americas had separated along the south Atlantic, and subduction on the west coast of the Americas had commenced, resulting in

871-744: The Bering Strait on the Pacific side and the Greenland Scotland Ridge on the Atlantic side. It is mostly covered by sea ice throughout the year and almost completely in winter . The Arctic Ocean's surface temperature and salinity vary seasonally as the ice cover melts and freezes; its salinity is the lowest on average of the five major oceans, due to low evaporation , heavy fresh water inflow from rivers and streams, and limited connection and outflow to surrounding oceanic waters with higher salinities. The summer shrinking of

938-790: The Blood Reserve Formation and the St. Mary River Formation in southern Alberta; by the Eastend Formation in southern Saskatchewan; and by the Fox Hills Formation in Montana. To the east, it merges into the Pierre Shale . The Bearpaw Formation is famous for its well-preserved ammonite fossils. These include Placenticeras meeki , Placenticeras intercalare , Hoploscaphites , and Sphenodiscus ,

1005-608: The Cretaceous period, the Canadian Basin opened, and tectonic activity due to the assembly of Alaska caused hydrocarbons to migrate toward what is now Prudhoe Bay. At the same time, sediments shed off the rising Canadian Rockies built out the large Mackenzie Delta. The rifting apart of the supercontinent Pangea , beginning in the Triassic period, opened the early Atlantic Ocean. Rifting then extended northward, opening

1072-735: The Cretaceous Seaway , the Niobraran Sea , the North American Inland Sea , the Western Interior Sea and sometimes nicknamed "Hell's Aquarium" ) was a large inland sea that split the continent of North America into two landmasses for 34 million years. The ancient sea, which existed from the early Late Cretaceous (100 Ma ) to the earliest Paleocene (66 Ma), connected the Gulf of Mexico to

1139-614: The Eurasian Basin , which is 4,000–4,500 m (13,100–14,800 ft) deep, and the Amerasian Basin (sometimes called the North American or Hyperborean Basin), which is about 4,000 m (13,000 ft) deep. The bathymetry of the ocean bottom is marked by fault block ridges, abyssal plains , ocean deeps , and basins. The average depth of the Arctic Ocean is 1,038 m (3,406 ft). The deepest point

1206-655: The Franz Josef Land ). The crystalline basement rocks of mountains around the Arctic Ocean were recrystallized or formed during the Ellesmerian orogeny, the regional phase of the larger Caledonian orogeny in the Paleozoic Era. Regional subsidence in the Jurassic and Triassic periods led to significant sediment deposition, creating many of the reservoirs for current day oil and gas deposits. During

1273-584: The Independence I and Independence II cultures of northeastern Canada and Greenland ( c.  2400–1800 BC and c.  800–1 BC ); and the Groswater of Labrador and Nunavik . The Dorset culture spread across Arctic North America between 500 BC and AD 1500. The Dorset were the last major Paleo-Eskimo culture in the Arctic before the migration east from present-day Alaska of

1340-518: The Laramide orogeny , the early phase of growth of the modern Rocky Mountains . The Western Interior Seaway may be seen as a downwarping of the continental crust ahead of the growing Laramide/Rockies mountain chain. The earliest phase of the seaway began in the mid-Cretaceous when an arm of the Arctic Ocean transgressed south over western North America; this formed the Mowry Sea, so named for

1407-583: The Mowry Shale , an organic-rich rock formation . In the south, the Gulf of Mexico was originally an extension of the Tethys Ocean . In time, the southern embayment merged with the Mowry Sea in the late Cretaceous, forming a completed seaway, creating isolated environments for land animals and plants. Relative sea levels fell multiple times , as a margin of land temporarily rose above the water along

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1474-670: The Northwest Passage , to " Cathay " ( China ) caused water to win out, and by 1723 mapmakers such as Johann Homann featured an extensive "Oceanus Septentrionalis" at the northern edge of their charts. The few expeditions to penetrate much beyond the Arctic Circle in that era added only small islands, such as Novaya Zemlya (11th century) and Spitzbergen (1596), though, since these were often surrounded by pack-ice , their northern limits were not so clear. The makers of navigational charts , more conservative than some of

1541-643: The Thule people , ancestors of the modern Inuit . The Thule Tradition lasted from about 200 BC to AD 1600, arising around the Bering Strait and later encompassing almost the entire Arctic region of North America. The Thule people were the ancestors of the Inuit, who now live in Alaska, Northwest Territories , Nunavut , Nunavik (northern Quebec), Labrador and Greenland. For much of European history ,

1608-680: The baculite Baculites compressus and the bivalve Inoceramus , some of which are mined south-central Alberta to produce the organic gemstone ammolite. Other fossils found in this formation include many types of shellfish , bony fish , sharks , rays , birds, and marine reptiles like mosasaurs such as Prognathodon overtoni and Plioplatecarpus peckensis , plesiosaurs such as Dolichorhynchops herschelensis , Albertonectes and Nakonanectes , and sea turtles . Dinosaur remains have occasionally been discovered, presumably from carcasses that washed out to sea. Western Interior Seaway The Western Interior Seaway (also called

1675-677: The Arctic Ocean as mafic oceanic crust material erupted out of a branch of Mid-Atlantic Ridge. The Amerasia Basin may have opened first, with the Chukchi Borderland moved along to the northeast by transform faults. Additional spreading helped to create the "triple-junction" of the Alpha-Mendeleev Ridge in the Late Cretaceous epoch . Throughout the Cenozoic Era, the subduction of the Pacific plate,

1742-617: The Arctic Ocean has a uniquely complex system of water flow. It resembles some hydrological features of the Mediterranean Sea , referring to its deep waters having only limited communication through the Fram Strait with the Atlantic Basin , "where the circulation is dominated by thermohaline forcing". The Arctic Ocean has a total volume of 18.07 × 10 km , equal to about 1.3% of the World Ocean. Mean surface circulation

1809-581: The Arctic Ocean. Much of the Arctic ice pack is also covered in snow for about 10 months of the year. The maximum snow cover is in March or April—about 20–50 cm (7.9–19.7 in) over the frozen ocean. The climate of the Arctic region has varied significantly during the Earth's history. During the Paleocene–Eocene Thermal Maximum 55 million years ago, when the global climate underwent

1876-653: The Arctic Ocean: Different authorities put various marginal seas in either the Arctic Ocean or the Atlantic Ocean, including: Hudson Bay , Baffin Bay , the Norwegian Sea , and Hudson Strait . The main islands and archipelagos in the Arctic Ocean are, from the prime meridian west: There are several ports and harbours on the Arctic Ocean. The ocean's Arctic shelf comprises

1943-480: The Canadian Archipelago. As noted, the process of ice formation and movement is a key driver in Arctic Ocean circulation and the formation of water masses. With this dependence, the Arctic Ocean experiences variations due to seasonal changes in sea ice cover. Sea ice movement is the result of wind forcing, which is related to a number of meteorological conditions that the Arctic experiences throughout

2010-739: The Dakotas and retreated south towards the Gulf of Mexico . This shrunken and final regressive phase is sometimes called the Pierre Seaway . During the early Paleocene , parts of the Western Interior Seaway still occupied areas of the Mississippi Embayment , submerging the site of present-day Memphis . Later transgression, however, was associated with the Cenozoic Tejas sequence , rather than with

2077-577: The European region of the Arctic Ocean was heavily contested : the Allied commitment to resupply the Soviet Union via its northern ports was opposed by German naval and air forces. Since 1954 commercial airlines have flown over the Arctic Ocean (see Polar route ). The Arctic Ocean occupies a roughly circular basin and covers an area of about 14,056,000 km (5,427,000 sq mi), almost

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2144-670: The Fram Strait is what allows for both inflow and outflow on the Atlantic side of the Arctic Ocean. Because of this, it is influenced by the Coriolis force , which concentrates outflow to the East Greenland Current on the western side and inflow to the Norwegian Current on the eastern side. Pacific water also exits along the west coast of Greenland and the Hudson Strait (1–2 Sv), providing nutrients to

2211-669: The Lomonosov Ridge, which appears to be continental crust separated from the Barents-Kara Shelf in the Paleocene and then starved of sediment. It may contain up to 10 billion barrels of oil. The Gakkel Ridge rift is also poorly understand and may extend into the Laptev Sea. In large parts of the Arctic Ocean, the top layer (about 50 m [160 ft]) is of lower salinity and lower temperature than

2278-720: The North American polar region goes back at least 17,000–50,000 years, during the Wisconsin glaciation . At this time, falling sea levels allowed people to move across the Bering land bridge that joined Siberia to northwestern North America (Alaska), leading to the Settlement of the Americas . Early Paleo-Eskimo groups included the Pre-Dorset ( c.  3200–850 BC ); the Saqqaq culture of Greenland (2500–800 BC);

2345-461: The Western Interior Seaway went through multiple periods of anoxia , when the bottom water was devoid of oxygen and the water column was stratified. At the end of the Cretaceous, continued Laramide uplift hoisted the sandbanks (sandstone) and muddy brackish lagoons (shale), thick sequences of silt and sandstone still seen today as the Laramie Formation , while low-lying basins between them gradually subsided. The Western Interior Seaway divided across

2412-650: The ancestral Transcontinental Arch , each time rejoining the separated, divergent land populations, allowing a temporary mixing of newer species before again separating the populations. At its largest, the Western Interior Seaway stretched from the Rockies east to the Appalachian Mountains , some 1,000 km (620 mi) wide. At its deepest, it may have been only 800 or 900 metres (2,600 or 3,000 ft) deep, shallow in terms of seas. Two great continental watersheds drained into it from east and west, diluting its waters and bringing resources in eroded silt that formed shifting delta systems along its low-lying coasts. There

2479-608: The average winter value of 15,600,000 km (6,023,200 sq mi). The seasonal variations are about 7,000,000 km (2,702,700 sq mi), with the maximum in April and minimum in September. The sea ice is affected by wind and ocean currents, which can move and rotate very large areas of ice. Zones of compression also arise, where the ice piles up to form pack ice. Icebergs occasionally break away from northern Ellesmere Island , and icebergs are formed from glaciers in western Greenland and extreme northeastern Canada. Icebergs are not sea ice but may become embedded in

2546-441: The collision of India with Eurasia, and the continued opening of the North Atlantic created new hydrocarbon traps. The seafloor began spreading from the Gakkel Ridge in the Paleocene Epoch and the Eocene Epoch, causing the Lomonosov Ridge to move farther from land and subside. Because of sea ice and remote conditions, the geology of the Arctic Ocean is still poorly explored. The Arctic Coring Expedition drilling shed some light on

2613-437: The explorers who travelled closer and closer to the pole reported, the polar ice cap is quite thick and persists year-round. Fridtjof Nansen was the first to make a nautical crossing of the Arctic Ocean, in the Fram Expedition from 1893 to 1896. The first surface crossing of the ocean was led by Wally Herbert in 1969, in a dog sled expedition from Alaska to Svalbard , with air support. The first nautical transit of

2680-412: The flightless Hesperornis that had stout legs for swimming through water and tiny wings used for marine steering rather than flight; and the tern-like Ichthyornis , an early avian with a toothy beak. Ichthyornis shared the sky with large pterosaurs such as Nyctosaurus and Pteranodon . Pteranodon fossils are very common; it was probably a major participant in the surface ecosystem, though it

2747-440: The formation of Atlantic Deep Water. The overturning of this water plays a key role in global circulation and the moderation of climate. In the depth range of 150–900 m (490–2,950 ft) is a water mass referred to as Atlantic Water. Inflow from the North Atlantic Current enters through the Fram Strait, cooling and sinking to form the deepest layer of the halocline, where it circles the Arctic Basin counter-clockwise. This

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2814-456: The ice has been quoted at 50%. The US National Snow and Ice Data Center (NSIDC) uses satellite data to provide a daily record of Arctic sea ice cover and the rate of melting compared to an average period and specific past years, showing a continuous decline in sea ice extent. In September 2012, the Arctic ice extent reached a new record minimum. Compared to the average extent (1979–2000), the sea ice had diminished by 49%. Human habitation in

2881-497: The increasing influence of Atlantic water heat in melting sea ice in the eastern Arctic. The most recent estimates, for 2016–2018, indicate the oceanic heat flux to the surface has now overtaken the atmospheric flux in the eastern Eurasian Basin. Over the same period the weakening halocline stratification has coincided with increasing upper ocean currents thought to be associated with declining sea ice, indicate increasing mixing in this region. In contrast direct measurements of mixing in

2948-399: The massive 4-to-5-metre (13 to 16 ft) long Xiphactinus , larger than any modern bony fish . Other sea life included invertebrates such as mollusks , ammonites , squid-like belemnites , and plankton including coccolithophores that secreted the chalky platelets that give the Cretaceous its name, foraminiferans and radiolarians . The seaway was home to early birds, including

3015-416: The more fanciful cartographers, tended to leave the region blank, with only fragments of known coastline sketched in. This lack of knowledge of what lay north of the shifting barrier of ice gave rise to a number of conjectures. In England and other European nations, the myth of an " Open Polar Sea " was persistent. John Barrow , longtime Second Secretary of the British Admiralty , promoted exploration of

3082-448: The north polar regions remained largely unexplored and their geography conjectural. Pytheas of Massilia recorded an account of a journey northward in 325 BC, to a land he called " Eschate Thule ", where the Sun only set for three hours each day and the water was replaced by a congealed substance "on which one can neither walk nor sail". He was probably describing loose sea ice known today as " growlers " or "bergy bits"; his "Thule"

3149-400: The north pole was made in 1958 by the submarine USS Nautilus , and the first surface nautical transit occurred in 1977 by the icebreaker NS Arktika . Since 1937, Soviet and Russian manned drifting ice stations have extensively monitored the Arctic Ocean. Scientific settlements were established on the drift ice and carried thousands of kilometres by ice floes . In World War II ,

3216-471: The pack ice. Icebergs pose a hazard to ships, of which the Titanic is one of the most famous. The ocean is virtually icelocked from October to June, and the superstructure of ships are subject to icing from October to May. Before the advent of modern icebreakers, ships sailing the Arctic Ocean risked being trapped or crushed by sea ice (although the Baychimo drifted through the Arctic Ocean untended for decades despite these hazards). The Arctic Ocean

3283-484: The previous event responsible for the seaway. The Western Interior Seaway was a shallow sea, filled with abundant marine life. Interior seaway denizens included predatory marine reptiles such as plesiosaurs , and mosasaurs . Other marine life included sharks such as Squalicorax , Cretoxyrhina , and the giant shellfish-eating Ptychodus mortoni (believed to be 10 metres (33 ft) long); and advanced bony fish including Pachyrhizodus , Enchodus , and

3350-414: The region from 1818 to 1845 in search of this. In the United States in the 1850s and 1860s, the explorers Elisha Kane and Isaac Israel Hayes both claimed to have seen part of this elusive body of water. Even quite late in the century, the eminent authority Matthew Fontaine Maury included a description of the Open Polar Sea in his textbook The Physical Geography of the Sea (1883). Nevertheless, as all

3417-520: The rest. It remains relatively stable because the salinity effect on density is bigger than the temperature effect. It is fed by the freshwater input of the big Siberian and Canadian rivers ( Ob , Yenisei , Lena , Mackenzie ), the water of which quasi floats on the saltier, denser, deeper ocean water. Between this lower salinity layer and the bulk of the ocean lies the so-called halocline , in which both salinity and temperature rise with increasing depth. Because of its relative isolation from other oceans,

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3484-478: The role of salinity in density. When water reaches the basin, it is pushed by strong winds into a large circular current called the Beaufort Gyre . Water in the Beaufort Gyre is far less saline than that of the Chukchi Sea due to inflow from large Canadian and Siberian rivers. The final defined water mass in the Arctic Ocean is called Arctic Surface Water and is found in the depth range of 150–200 m (490–660 ft). The most important feature of this water mass

3551-462: The sea that sink over the continental shelf into the western Arctic Ocean and create a halocline. This water is met by Greenland Sea Deep Water, which forms during the passage of winter storms. As temperatures cool dramatically in the winter, ice forms, and intense vertical convection allows the water to become dense enough to sink below the warm saline water below. Arctic Bottom Water is critically important because of its outflow, which contributes to

3618-433: The seaway retreated toward the southwest, the marine sediments of the Bearpaw became covered by the deltaic and coastal plain sediments of the overlying formations. The Bearpaw Formation conformably overlies the Dinosaur Park Formation of the Belly River Group in central Alberta, and the Judith River Formation in the plains to the east and Montana. It is overlain by the Horseshoe Canyon Formation in central Alberta; by

3685-403: The seaway. Many species can easily fit in the palm of the hand, while some like Inoceramus (Haploscapha) grandis could be well over a meter in diameter. Entire schools of fish sometimes sought shelter within the shell of the giant Platyceramus . The shells of the genus are known for being composed of prismatic calcitic crystals that grew perpendicular to the surface, and fossils often retain

3752-408: The shelf region that begins as inflow from the Pacific passes through the narrow Bering Strait at an average rate of 0.8 Sverdrups and reaches the Chukchi Sea . During the winter, cold Alaskan winds blow over the Chukchi Sea, freezing the surface water and pushing this newly formed ice out to the Pacific. The speed of the ice drift is roughly 1–4 cm/s. This process leaves dense, salty waters in

3819-411: The size of Antarctica . The coastline is 45,390 km (28,200 mi) long. It is the only ocean smaller than Russia , which has a land area of 16,377,742 km (6,323,482 sq mi). The Arctic Ocean is surrounded by the land masses of Eurasia (Russia and Norway), North America ( Canada and the U.S. state of Alaska), Greenland, and Iceland . Note: Some parts of the areas listed in

3886-409: The summer months. There is also evidence that the drift is associated with the phase of the Arctic Oscillation and Atlantic Multidecadal Oscillation . Much of the Arctic Ocean is covered by sea ice that varies in extent and thickness seasonally. The mean extent of the Arctic sea ice has been continuously decreasing in the last decades, declining at a rate of currently 12.85% per decade since 1980 from

3953-441: The summer, the SLP contrast is smaller, producing weaker winds. A final example of seasonal pressure system movement is the low pressure system that exists over the Nordic and Barents Seas. It is an extension of the Icelandic Low , which creates cyclonic ocean circulation in this area. The low shifts to centre over the North Pole in the summer. These variations in the Arctic all contribute to ice drift reaching its weakest point during

4020-445: The table are located in the Atlantic Ocean . Other consists of Gulfs , Straits , Channels and other parts without specific names and excludes Exclusive Economic Zones . The Arctic Ocean is connected to the Pacific Ocean by the Bering Strait and to the Atlantic Ocean through the Greenland Sea and Labrador Sea . (The Iceland Sea is sometimes considered part of the Greenland Sea, and sometimes separate.) The largest seas in

4087-419: The upper 100–150 m (330–490 ft) of ocean water cools to the freezing point for sea ice to form. In the winter, the relatively warm ocean water exerts a moderating influence, even when covered by ice. This is one reason why the Arctic does not experience the extreme temperatures seen on the Antarctic continent . There is considerable seasonal variation in how much pack ice of the Arctic ice pack covers

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4154-422: The western Arctic indicate the Atlantic water heat remains isolated at intermediate depths even under the 'perfect storm' conditions of the Great Arctic Cyclone of 2012 . Waters originating in the Pacific and Atlantic both exit through the Fram Strait between Greenland and Svalbard Island, which is about 2,700 m (8,900 ft) deep and 350 km (220 mi) wide. This outflow is about 9 Sv. The width of

4221-418: The world; it holds large oil and gas reserves. The Chukchi shelf forms the border between Russian and the United States as stated in the USSR–USA Maritime Boundary Agreement . The whole area is subject to international territorial claims . The Chukchi Plateau extends from the Chukchi Sea Shelf. An underwater ridge , the Lomonosov Ridge , divides the deep sea North Polar Basin into two oceanic basins :

4288-426: The year. For example, the Beaufort High—an extension of the Siberian High system—is a pressure system that drives the anticyclonic motion of the Beaufort Gyre. During the summer, this area of high pressure is pushed out closer to its Siberian and Canadian sides. In addition, there is a sea level pressure (SLP) ridge over Greenland that drives strong northerly winds through the Fram Strait, facilitating ice export. In

4355-430: Was found in only the southern reaches of the seaway. Inoceramids (oyster-like bivalve molluscs) were well-adapted to life in the oxygen-poor bottom mud of the seaway. These left abundant fossils in the Kiowa , Greenhorn , Niobrara , Mancos , and Pierre formations. There is great variety in the shells and the many distinct species have been dated and can be used to identify specific beds in those rock formations of

4422-495: Was little sedimentation on the eastern shores of the seaway; the western boundary, however, consisted of a thick clastic wedge eroded eastward from the Sevier orogenic belt . The western shore was thus highly variable, depending on variations in sea level and sediment supply. Widespread carbonate deposition suggests that the seaway was warm and tropical, with abundant calcareous planktonic algae . Remnants of these deposits are found in northwest Kansas. A prominent example

4489-417: Was probably Norway , though the Faroe Islands or Shetland have also been suggested. Early cartographers were unsure whether to draw the region around the North Pole as land (as in Johannes Ruysch 's map of 1507, or Gerardus Mercator 's map of 1595) or water (as with Martin Waldseemüller 's world map of 1507). The fervent desire of European merchants for a northern passage, the Northern Sea Route or

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