Laurentide Ice Sheet
The Laurentide Ice Sheet was a massive sheet of ice that covered millions of square kilometers, including most of Canada and a large portion of the northern United States, multiple times during the Quaternary glacial epochs, from 2.588 ± 0.005 million years ago to the present. The last advance covered most of northern North America between c. 95,000 and c. 20,000 years before the present day and, among other geomorphological effects, gouged out the five Great Lakes and the hosts of smaller lakes of the Canadian Shield. These lakes extend from the eastern Northwest Territories, through most of northern Canada, the upper Midwestern United States to the Finger Lakes, through Lake Champlain and Lake George areas of New York, across the northern Appalachians into and through all of New England and Nova Scotia. At times, the ice sheet's southern margin included the present-day sites of northeastern coastal towns and cities such as Boston and New York City and Great Lakes coastal cities and towns as far south as Chicago and St. Louis and followed the present course of the Missouri River up to the northern slopes of the Cypress Hills, beyond which it merged with the Cordilleran Ice Sheet.
The ice coverage extended as far south as 38 degrees latitude mid-continent. This ice sheet was the primary feature of the Pleistocene epoch in North America referred to as the ice age, it was up to 2 mi thick in Nunavik, Canada, but much thinner at its edges, where nunataks were common in hilly areas. It created much of the surface geology of southern Canada and the northern United States, leaving behind glacially scoured valleys, moraines and glacial till, it caused many changes to the shape and drainage of the Great Lakes. As but one of many examples, near the end of the last ice age, Lake Iroquois extended well beyond the boundaries of present-day Lake Ontario, drained down the Hudson River into the Atlantic Ocean, its cycles of growth and melting were a decisive influence on global climate during its existence. This is because it served to divert the jet stream which would otherwise flow from the warm Pacific Ocean through Montana and Minnesota to the south; that gave the Southwestern United States, otherwise a desert, abundant rainfall during ice ages, in extreme contrast to most other parts of the world which became exceedingly dry, though the effect of ice sheets in Europe had an analogous effect on the rainfall in Afghanistan, parts of Iran western Pakistan in winter, as well as North Africa.
Its melting caused major disruptions to the global climate cycle, because the huge influx of low-salinity water into the Arctic Ocean via the Mackenzie River is believed to have disrupted the formation of North Atlantic Deep Water, the saline, deep water that flows from the Greenland Sea. That interrupted the thermohaline circulation, creating the brief Younger Dryas cold epoch and a temporary re-advance of the ice sheet, which did not retreat from Nunavik until 6,500 years ago. During the Pre-Illinoian Stage, the Laurentide Ice Sheet extended as far south as the Missouri and Ohio River valleys; the ultimate collapse of the Laurentide Ice Sheet is suspected to have influenced European agriculture indirectly through the rise of global sea levels. Canada's oldest ice is a 20,000-year-old remnant of the Laurentide Ice Sheet called the Barnes Ice Cap, on central Baffin Island. During the Late Pleistocene, the Laurentide ice sheet reached from the Rocky Mountains eastward through the Great Lakes, into New England, covering nearly all of Canada east of the Rocky Mountains.
Three major ice centers formed in North America: the Labrador and Cordilleran. The Cordilleran covered the region from the Pacific Ocean to the eastern front of the Rocky Mountains and the Labrador and Keewatin fields are referred to as the Laurentide Ice Sheet. Central North America has evidence of the numerous sublobes; the Keewatin covered the western interior plains of North America from the Mackenzie River to the Missouri River and the upper reaches of the Mississippi River. The Labrador covered spread over eastern Canada and the northeastern part of the United States abutting the Keewatin lobe in the western Great Lakes and Mississippi valley. Cordilleran Ice Sheet covered up to 2,500,000 square kilometres at the Last Glacial Maximum; the eastern edge abutted the Laurentide ice sheet. The sheet was anchored in the Coast Mountains of British Columbia and Alberta, south into the Cascade Range of Washington; that is one and a half times the water held in the Antarctic. Anchored in the mountain backbone of the west coast, the ice sheet dissipated north of the Alaska Range where the air was too dry to form glaciers.
It is believed that the Cordilleran ice melted in less than 4000 years. The water created numerous Proglacial lakes along the margins such as Lake Missoula leading to catastrophic floods as with the Missoula Floods. Much of the topography of Eastern Washington and northern Montana and North Dakota was affected. Keewatin Ice flow has had four or five primary lobes identified ice divides extending from a dome over west-central Keewatin. Two of the lobes abut the adjacent Baffin ice sheets; the primary lobes flow towards Saskatchewan. Ice flowed across all of Maine and into the Gulf of St. Lawrence covering the Maritime Provinces; the Appalachian Ice Complex, flowed from the Gaspé Peninsula over New Brunswick, the Magdalen Shelf, Nova Scotia. The Labrador flow extended across the mouth of the St. Lawrence River, reaching the Gaspé Peninsula and across Chaleur Bay. From the Escuminac center on the
Cotton is a soft, fluffy staple fiber that grows in a boll, or protective case, around the seeds of the cotton plants of the genus Gossypium in the mallow family Malvaceae. The fiber is pure cellulose. Under natural conditions, the cotton bolls will increase the dispersal of the seeds; the plant is a shrub native to tropical and subtropical regions around the world, including the Americas, Africa and India. The greatest diversity of wild cotton species is found followed by Australia and Africa. Cotton was independently domesticated in the New Worlds; the fiber is most spun into yarn or thread and used to make a soft, breathable textile. The use of cotton for fabric is known to date to prehistoric times. Although cultivated since antiquity, it was the invention of the cotton gin that lowered the cost of production that led to its widespread use, it is the most used natural fiber cloth in clothing today. Current estimates for world production are about 25 million tonnes or 110 million bales annually, accounting for 2.5% of the world's arable land.
China is the world's largest producer of cotton. The United States has been the largest exporter for many years. In the United States, cotton is measured in bales, which measure 0.48 cubic meters and weigh 226.8 kilograms. There are four commercially grown species of cotton, all domesticated in antiquity: Gossypium hirsutum – upland cotton, native to Central America, the Caribbean and southern Florida Gossypium barbadense – known as extra-long staple cotton, native to tropical South America Gossypium arboreum – tree cotton, native to India and Pakistan Gossypium herbaceum – Levant cotton, native to southern Africa and the Arabian Peninsula The two New World cotton species account for the vast majority of modern cotton production, but the two Old World species were used before the 1900s. While cotton fibers occur in colors of white, brown and green, fears of contaminating the genetics of white cotton have led many cotton-growing locations to ban the growing of colored cotton varieties; the word "cotton" has Arabic origins, derived from the Arabic word قطن.
This was the usual word for cotton in medieval Arabic. The word entered the Romance languages in the mid-12th century, English a century later. Cotton fabric was known to the ancient Romans as an import but cotton was rare in the Romance-speaking lands until imports from the Arabic-speaking lands in the medieval era at transformatively lower prices; the earliest evidence of cotton use in the Indian subcontinent has been found at the site of Mehrgarh and Rakhigarhi where cotton threads have been found preserved in copper beads. Cotton cultivation in the region is dated to the Indus Valley Civilization, which covered parts of modern eastern Pakistan and northwestern India between 3300 and 1300 BC; the Indus cotton industry was well-developed and some methods used in cotton spinning and fabrication continued to be used until the industrialization of India. Between 2000 and 1000 BC cotton became widespread across much of India. For example, it has been found at the site of Hallus in Karnataka dating from around 1000 BC.
Cotton bolls discovered in a cave near Tehuacán, have been dated to as early as 5500 BC, but this date has been challenged. More securely dated is the domestication of Gossypium hirsutum in Mexico between around 3400 and 2300 BC. In Peru, cultivation of the indigenous cotton species Gossypium barbadense has been dated, from a find in Ancon, to c. 4200 BC, was the backbone of the development of coastal cultures such as the Norte Chico and Nazca. Cotton was grown upriver, made into nets, traded with fishing villages along the coast for large supplies of fish; the Spanish who came to Mexico and Peru in the early 16th century found the people growing cotton and wearing clothing made of it. The Greeks and the Arabs were not familiar with cotton until the Wars of Alexander the Great, as his contemporary Megasthenes told Seleucus I Nicator of "there being trees on which wool grows" in "Indica"; this may be a reference to "tree cotton", Gossypium arboreum, a native of the Indian subcontinent. According to the Columbia Encyclopedia: Cotton has been spun and dyed since prehistoric times.
It clothed the people of ancient India and China. Hundreds of years before the Christian era, cotton textiles were woven in India with matchless skill, their use spread to the Mediterranean countries. In Iran, the history of cotton dates back to the Achaemenid era; the planting of cotton was common in Merv and Pars of Iran. In Persian poets' poems Ferdowsi's Shahname, there are references to cotton. Marco Polo refers to the major products including cotton. John Chardin, a French traveler of the 17th century who visited Safavid Persia, spoke approvingly of the vast cotton farms of Persia. During the Han dynasty, cotton was grown by Chinese peoples in the southern Chinese province of Yunnan. Egyptians spun cotton in the first seven centuries of the Christian era. Handheld roller cotton gins had been used in India since the 6th century, was introduced to other countries from there. Between the 12th and 14th centuries, dual-roller gins appeared in China; the Indian version of the dual-roller gin was preval
Prince of Wales Island (Alaska)
Prince of Wales Island is one of the islands of the Alexander Archipelago in the Alaska Panhandle. It is the 97th-largest island in the world; the island is 135 miles long, 45 miles wide and has an area of 2,577 sq mi, about 1/10 the size of Ireland and larger than the state of Delaware. 3,000 people live on the island. Craig is the largest community; some 750 people live in a long-established village that grew with the fishing industry. Hollis was a boom and bust mining town from 1900 to about 1915. Abandoned, it was re-established as a logging camp in the'50s, it is the location of the ferry terminal. Mountain peaks, all but the tallest of which were buried by Pleistocene glaciation, reach over 3,000 feet. Fjords, steep-sided mountains, dense forests characterize the island. Extensive tracts of limestone include karst features such as El Capitan Pit, at 598.3 feet the deepest vertical shaft in the United States. Moist, maritime conditions dominate the weather; the Tongass National Forest covers most of the island.
Within the forest and on the island are the Karta River Wilderness and the South Prince of Wales Wilderness. Many of its wildlife, such as the Prince of Wales flying squirrel, are found nowhere else; the island is in the Prince of Wales-Hyder Census Area. Prince of Wales Island is the homeland of the indigenous Kaigani Haida people. Kaigani is a mispronunciation of the Tlingit word x'aax' aani, which translates to "crabapple country"; the Tlingit name for the island is Taan, meaning "sea lion". The island is traditional Tlingit territory; the Haida migrated into the area in the late 18th century. Abandoned Haida villages still have Tlingit names. In 1741, Aleksei Chirikov, commanding a ship on Vitus Bering's second voyage of exploration out of Kamchatka, made the first recorded European landfall on the northwest coast of North America at Baker Island on the west coast of Prince of Wales Island, he did not stop for any length of time there. The next European arrival was in 1774, when Juan Pérez led a Spanish expedition sailing in a 39-foot boat from La Paz, Mexico.
They reached Sumez Island off of Prince of Wales' west coast. In 1779 a British expedition under Captain James Cook passed Prince of Wales Island. Comte de La Perouse led a French expedition to the area in 1786. Karta Bay is the site of the first salmon saltery in Alaska. Settlers began mining of gold and other metals on the island in the late 19th century, as European Americans entered the area to exploit the natural resources. Gold production came from underground lode mines exploiting: gold-bearing quartz veins in metamorphic rocks. Uranium was mined at Bokan Mountain in the 1970s. Logging was the mainstay of the collective Prince of Wales economy through most of the 20th century; the decline of the industry since the late 20th century has resulted in only a few small-scale sawmills operating. In 1975, the Point Baker Association and others sued the United States Forest Service to prevent logging 400,000 acres on the northern portion of the island. In December 1975, Judge von der Heydt issued a ruling enjoining all clearcutting on the 400,000 acres on Northern Prince of Wales Island west of a line from the west side of Red Bay to the easternmost point of Calder Bay.
In March 1976, the United States Congress responded to the suit by passing the National Forest Management Act, which removed the injunction. Still, only half of the marketable timber was cut on the north end of the island. Road construction and logging on the north end of the island at Labouchere Bay commenced early in 1975. Living on a floating camp beginning with the retired tugboat Irene leased as a floating hotel, employees of Robertson & Sons began cutting trees, clearing stumps, blasting rock in order to build pads for mobile trailers for both the road construction and logging families; the camps were ready in early June for Robertson employees to bring in their families. Under the supervision of the US Forest Service, logging began in 1976. In 2010, Senators Lisa Murkowski and Mark Begich introduced S730 to privatize stands of old growth forests on the island. Tourism, including sport fishing, is an important part in Prince of Wales' economy. Two factors have led to the increase of tourism on the island.
Roads built for the logging companies years ago have enabled better access to different parts of the island for hiking and camping. The second was the new Inter-Island Ferry Authority. Commercial fishing provides the foundation of the economy for numerous towns on the island including Craig, Hydaburg, Port Protection and Point Baker. During the summer and seiners both fish for all five species of Pacific salmon. Longliners bring up black cod. Dungeness crab and shrimp seasons are open throughout the year. During the winter there are dive fisheries for geoducks, sea cucumbers, sea urchins. Since Prince of Wales Island is entirely made up of federal land, the two ranger districts on the island provide employment for a number of residents. Mineral exploration continues at many projects on Prince of Wales Island; the only producing uranium mine in the entire state of Alaska was located on the island, the Ross-Ad
History of North America
History of North America encompasses the past developments of people populating the continent of North America. While it was believed that continent first became a human habitat when people migrated across the Bering Sea 40,000 to 17,000 years ago, recent discoveries may have pushed those estimates back at least another 90,000 years. Regardless, migrants settled in many locations on the continent, from the Inuit of the far north to the Mayans and Aztecs of the south; these isolated communities each developed their own unique ways of life and cultures, their interaction with one another was limited in comparison to the extensive trade and conflict of civilizations across the Atlantic in Europe and Asia. Records of European travel to North America begin with the Norse in the tenth century CE. In 985, they founded a settlement on Greenland, they explored the east coast of Canada, but their settlements there were much smaller and shorter-lived. With the Age of Exploration and the voyages of Christopher Columbus, Europeans began to arrive in the Americas in large numbers and to develop colonial ambitions for both North and South America.
Columbus' "discovery" of America is a contested idea because the Americas were heavily populated by the indigenous Native American peoples, who had developed distinctive civilizations in their own right. After Columbus, influxes of Europeans soon overwhelmed the native population. North America became a staging ground for ongoing European rivalries; the continent was divided by three prominent European powers: England and Spain. The influences of colonization by these states on North American cultures are still apparent today. Conflict over resources on North America ensued in various wars between these powers, but the new European colonies developed desires for independence. Revolutions, such as the American Revolution and Mexican War of Independence, created new, independent states that came to dominate North America; the Canadian Confederation formed in 1867. From the 19th to 21st centuries, North American states have developed deeper connections with each other. Although some conflicts have occurred, the continent has for the most part enjoyed peace and general cooperation between its states, as well as open commerce and trade between them.
Modern developments include the opening of free trade agreements, extensive immigration from Mexico and Latin America, drug trafficking concerns in these regions. The specifics of Paleo-Indians' migration to and throughout the Americas, including the exact dates and routes traveled, are subject to ongoing research and discussion. For years, the traditional theory has been that these early migrants moved into the Beringia land bridge between eastern Siberia and present-day Alaska around 40,000–17,000 years ago, when sea levels were lowered due to the Quaternary glaciation; these people are believed to have followed herds of now-extinct pleistocene megafauna along ice-free corridors that stretched between the Laurentide and Cordilleran ice sheets. Another route proposed is that, either on foot or using primitive boats, they migrated down the Pacific coast to South America. Evidence of the latter would since have been covered by a sea level rise of hundreds of meters following the last ice age.
Archaeologists contend that Paleo-Indian migration out of Beringia, ranges from 40,000 to around 16,500 years ago. This time range promises to continue as such for years to come; the few agreements achieved to date are the origin from Central Asia, with widespread habitation of the Americas during the end of the last glacial period, or more what is known as the late glacial maximum, around 16,000–13,000 years before present. However, older alternative theories exist, including migration from Europe. Stone tools projectile points and scrapers, are the primary evidence of early human activity in the Americas. Crafted lithic flaked tools are used by archaeologists and anthropologists to classify cultural periods. Scientific evidence links indigenous Americans to Asian peoples eastern Siberian populations. Indigenous peoples of the Americas have been linked to North Asian populations by linguistic dialects, the distribution of blood types, in genetic composition as reflected by molecular data, such as DNA.
8,000–7,000 BCE the climate stabilized, leading to a rise in population and lithic technology advances, resulting in a more sedentary lifestyle. Before contact with Europeans, the indigenous peoples of North America were divided into many different polities, from small bands of a few families to large empires, they lived in numerous culture areas, which correspond to geographic and biological zones. Societies adapted their subsistence strategies to their homelands, some societies were hunter-gatherers, some horticulturists, some agriculturalists, many a mix of these. Native groups can be classified by their language family, it is important to note that people with similar languages did not always share the same material culture, nor were they always allies. The Archaic period in the Americas saw a changing environment featuring a warmer more arid climate and the disappearance of the last megafauna; the majority of population groups at this time were still mobile hunter-gatherers.
A stone tool is, in the most general sense, any tool made either or out of stone. Although stone tool-dependent societies and cultures still exist today, most stone tools are associated with prehistoric cultures that have become extinct. Archaeologists study such prehistoric societies, refer to the study of stone tools as lithic analysis. Ethnoarchaeology has been a valuable research field in order to further the understanding and cultural implications of stone tool use and manufacture. Stone has been used to make a wide variety of different tools throughout history, including arrow heads and querns. Stone tools may be made of either ground stone or chipped stone, a person who creates tools out of the latter is known as a flintknapper. Chipped stone tools are made from cryptocrystalline materials such as chert or flint, chalcedony, obsidian and quartzite via a process known as lithic reduction. One simple form of reduction is to strike stone flakes from a nucleus of material using a hammerstone or similar hard hammer fabricator.
If the goal of the reduction strategy is to produce flakes, the remnant lithic core may be discarded once it has become too small to use. In some strategies, however, a flintknapper reduces the core to a rough unifacial or bifacial preform, further reduced using soft hammer flaking techniques or by pressure flaking the edges. More complex forms of reduction include the production of standardized blades, which can be fashioned into a variety of tools such as scrapers, knives and microliths. In general terms, chipped stone tools are nearly ubiquitous in all pre-metal-using societies because they are manufactured, the tool stone is plentiful, they are easy to transport and sharpen. Archaeologists classify stone tools into industries that share distinctive technological or morphological characteristics. In 1969 in the 2nd edition of World Prehistory, Grahame Clark proposed an evolutionary progression of flint-knapping in which the "dominant lithic technologies" occurred in a fixed sequence from Mode 1 through Mode 5.
He assigned to them relative dates: Modes 1 and 2 to the Lower Palaeolithic, 3 to the Middle Palaeolithic, 4 to the Advanced and 5 to the Mesolithic. They were not to be conceived, however, as either universal—that is, they did not account for all lithic technology. Mode 1, for example, was in use in Europe. Clark's scheme was adopted enthusiastically by the archaeological community. One of its advantages was the simplicity of terminology; the transitions are of greatest interest. In the literature the stone tools used in the period of the Palaeolithic are divided into four "modes", each of which designate a different form of complexity, which in most cases followed a rough chronological order. KenyaStone tools found from 2011 to 2014 at Lake Turkana in Kenya, are dated to be 3.3 million years old, predate the genus Homo by half million years. The oldest known Homo fossil is 2.8 million years old compared to the 3.3 million year old stone tools. The stone tools may have been made by Australopithecus afarensis —also called Kenyanthropus platyops— the species whose best fossil example is Lucy, which inhabited East Africa at the same time as the date of the oldest stone tools.
Dating of the tools was by dating volcanic ash layers in which the tools were found and dating the magnetic signature of the rock at the site. EthiopiaGrooved and fractured animal bone fossils, made by using stone tools, were found in Dikika, Ethiopia near the remains of Selam, a young Australopithecus afarensis girl who lived about 3.3 million years ago. The earliest stone tools in the life span of the genus Homo are Mode 1 tools, come from what has been termed the Oldowan Industry, named after the type of site found in Olduvai Gorge, where they were discovered in large quantities. Oldowan tools were characterised by their simple construction; these cores were river pebbles, or rocks similar to them, struck by a spherical hammerstone to cause conchoidal fractures removing flakes from one surface, creating an edge and a sharp tip. The blunt end is the proximal surface. Oldowan is a percussion technology. Grasping the proximal surface, the hominid brought the distal surface down hard on an object he wished to detach or shatter, such as a bone or tuber.
The earliest known Oldowan tools yet found date from 2.6 million years ago, during the Lower Palaeolithic period, have been uncovered at Gona in Ethiopia. After this date, the Oldowan Industry subsequently spread throughout much of Africa, although archaeologists are unsure which Hominan species first developed them, with some speculating that it was Australopithecus garhi, others believing that it was in fact Homo habilis. Homo habilis was the hominin who used the tools for most of the Oldowan in Africa, but at about 1.9-1.8 million years ago Homo erectus inherited them. The Industry flourished in southern and eastern Africa between 2.6 and 1.7 million years ago, but was spread out of Africa and into Eurasia by travelling bands of H. erectus, who took it as far east as Java by 1.8 million years ago and Northern China by 1.6 million years ago. More complex, Mode 2 tools began to be developed through the Acheulean Industry, named after the site