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Huronian Glaciation
The Huronian glaciation (or Makganyene glaciation) was a period where several ice ages occurred during the deposition of the Huronian Supergroup, rather than a single continuous event as it is commonly misrepresented to be. The deposition of this group extended from 2.5 billion years ago (Gya) to 2.2 Gya, during the Siderian and Rhyacian periods of the Paleoproterozoic era. This led to the deposition of several diamictites. Most of the deposits of the Huronian are typical passive margin deposits in a marine setting. The diamictites within the Huronian are on par in thickness with Quaternary analogs. Evidence for the Huronian comes from glacial deposits identified within the stratigraphic record of the Huronian Supergroup. Within it are three distinct formations of diamictite, from the oldest to youngest, the Ramsay, Bruce, and Gowganda Formations. Although there are other glacial deposits recognized throughout the world, the Huronian is restricted to the North American ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ice Age
An ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages and greenhouse periods, during which there are no glaciers on the planet. Earth is currently in the Quaternary glaciation. Individual pulses of cold climate within an ice age are termed '' glacial periods'' (or, alternatively, ''glacials, glaciations, glacial stages, stadials, stades'', or colloquially, ''ice ages''), and intermittent warm periods within an ice age are called '' interglacials'' or ''interstadials''. In glaciology, ''ice age'' implies the presence of extensive ice sheets in both northern and southern hemispheres. By this definition, Earth is currently in an interglacial period—the Holocene. The amount of anthropogenic greenhouse gases emitted into Earth's oceans and atmosphere is predicted to prevent the next glacial period for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lake Huron
Lake Huron ( ) is one of the five Great Lakes of North America. Hydrologically, it comprises the easterly portion of Lake Michigan–Huron, having the same surface elevation as Lake Michigan, to which it is connected by the , Straits of Mackinac. It is shared on the north and east by the Canadian province of Ontario and on the south and west by the U.S. state of Michigan. The name of the lake is derived from early French explorers who named it for the Huron people inhabiting the region. The Huronian glaciation was named from evidence collected from Lake Huron region. The northern parts of the lake include the North Channel and Georgian Bay. Saginaw Bay is located in the southwest corner of the lake. The main inlet is the St. Marys River, and the main outlet is the St. Clair River. Geography By surface area, Lake Huron is the second-largest of the Great Lakes, with a surface area of —of which lies in Michigan; and lies in Ontario—making it the third-largest fre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rifting
In geology, a rift is a linear zone where the lithosphere is being pulled apart and is an example of extensional tectonics. Typical rift features are a central linear downfaulted depression, called a graben, or more commonly a half-graben with normal faulting and rift-flank uplifts mainly on one side. Where rifts remain above sea level they form a rift valley, which may be filled by water forming a rift lake. The axis of the rift area may contain volcanic rocks, and active volcanism is a part of many, but not all, active rift systems. Major rifts occur along the central axis of most mid-ocean ridges, where new oceanic crust and lithosphere is created along a divergent boundary between two tectonic plates. ''Failed rifts'' are the result of continental rifting that failed to continue to the point of break-up. Typically the transition from rifting to spreading develops at a triple junction where three converging rifts meet over a hotspot. Two of these evolve to the point ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tectonics
Tectonics (; ) are the processes that control the structure and properties of the Earth's crust and its evolution through time. These include the processes of mountain building, the growth and behavior of the strong, old cores of continents known as cratons, and the ways in which the relatively rigid plates that constitute the Earth's outer shell interact with each other. Tectonics also provide a framework for understanding the earthquake and volcanic belts that directly affect much of the global population. Tectonic studies are important as guides for economic geologists searching for fossil fuels and ore deposits of metallic and nonmetallic resources. An understanding of tectonic principles is essential to geomorphologists to explain erosion patterns and other Earth surface features. Main types of tectonic regime Extensional tectonics Extensional tectonics is associated with the stretching and thinning of the crust or the lithosphere. This type of tectonics is foun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Griquatown, Northern Cape
Griekwastad is a country town in South Africa. It is sometimes still called Griquatown (the meaning of the town's name in Afrikaans), a name which is now considered historical. The town is in the Northern Cape Province of South Africa by road west from the city of Kimberley. It was the first town to be established in the country north of the Orange River. History In 1801 William Anderson and Cornelius Kramer, of the London Missionary Society, established a station among the Griqua at ''Leeuwenkuil''. The site proved too arid for cultivation. In about 1805 they moved the station to another spring further up the valley and called it ''Klaarwater''. Their second choice was little better than their first, and for many years a lack of water prevented any further development. The name of the settlement was changed later to Griquatown or ''Griekwastad'' in Afrikaans. They lived among a mixed nomadic community of the Chaguriqua tribe and "bastaards" (people of mixed origin) from Pik ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canadian Northern Territories
Within the geographical areas of Canada, the ten provinces and three territories are sub-national administrative divisions under the jurisdiction of the Canadian Constitution. In the 1867 Canadian Confederation, three provinces of British North America—New Brunswick, Nova Scotia, and the Province of Canada (which upon Confederation was divided into Ontario and Quebec)—united to form a federation, becoming a fully independent country over the next century. Over its history, Canada's international borders have changed several times as it has added territories and provinces, making it the world's second-largest country by area. The major difference between a Canadian province and a territory is that provinces receive their power and authority from the ''Constitution Act, 1867'' (formerly called the ''British North America Act, 1867''), whereas territorial governments are creatures of statute with powers delegated to them by the Parliament of Canada. The powers flowing from t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chibougamau
Chibougamau () is the largest town in Nord-du-Québec, central Quebec, Canada. Located on Lake Gilman it has a population of 7,504 people (2016 Canadian Census). Chibougamau is surrounded by, but not part of, the local municipality of Eeyou Istchee James Bay Regional Government. Due to its remoteness from Lac Saint-Jean (over south-east) and Abitibi-Témiscamingue (over south-west) areas, Chibougamau provides services for a few smaller communities surrounding it (Mistissini, Oujé-Bougoumou and Chapais) and for the regional resource-based industries. Despite Chibougamau's remoteness, it is only about as far north as Winnipeg, and is south of any part of the mainland of England. Nearby are Lake Aux Dorés, which is fed by the Chibougamau River from the larger Chibougamau Lake, after which the town was named. ''Chibougamau'' means "Gathering place" in the Cree language. The neighbouring Cree village of Oujé-Bougoumou has the same name with a more traditional Cree spelling ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Black Hills
The Black Hills ( lkt, Ȟe Sápa; chy, Moʼȯhta-voʼhonáaeva; hid, awaxaawi shiibisha) is an isolated mountain range rising from the Great Plains of North America in western South Dakota and extending into Wyoming, United States. Black Elk Peak (formerly known as Harney Peak), which rises to , is the range's highest summit. The Black Hills encompass the Black Hills National Forest. The name of the hills in Lakota is ', meaning “the heart of everything that is." The Black Hills are considered a holy site. The hills are so called because of their dark appearance from a distance, as they are covered in evergreen trees. Native Americans have a long history in the Black Hills and consider it a sacred site. After conquering the Cheyenne in 1776, the Lakota took the territory of the Black Hills, which became central to their culture. In 1868, the U.S. government signed the Fort Laramie Treaty of 1868, establishing the Great Sioux Reservation west of the Missouri River, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gowganda
Gowganda is a Dispersed Rural Community and unincorporated place in geographic Nicol Township, Timiskaming District, in northeastern Ontario, Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by to .... It is at the outlet of the Montreal River from Lake Gowganda, and is on Ontario Highway 560. References External links Gowgandaprofile at the James Bay Frontier Travel Association North Ontario Fishing Maps Angler's Atlas map download Communities in Timiskaming District {{NorthernOntario-geo-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geochronometry
Geochronometry is a branch of stratigraphy aimed at the quantitative measurement of geologic time. It is considered a branch of geochronology. Brief history The measurement of geologic time is a long-standing problem of geology. Hallam, Anthony, 1983 – ''Great geological controversies''. Oxford University Press, Oxford, UK. When geology was at its beginnings, a major problem for stratigraphers was to find a reliable method for the measurement of time. In the eighteenth century, and during most of the nineteenth century, the ideas on the geologic time were indeed so controversial that the estimates for the age of the Earth encompassed the whole range from ca. 6000 years to 300 million years. The longer estimate came from Charles Darwin, who probably went closer to the truth because he had clear in mind that the evolution of life must have required a lot of time to take place. The current estimate of the age of the Earth is ca. 4500 million years. The solution of the dating prob ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diachronic
Synchrony and diachrony are two complementary viewpoints in linguistic analysis. A ''synchronic'' approach (from grc, συν- "together" and "time") considers a language at a moment in time without taking its history into account. Synchronic linguistics aims at describing a language at a specific point of time, often the present. In contrast, a ''diachronic'' (from "through" and "time") approach, as in historical linguistics, considers the development and evolution of a language through history. For example, the study of Middle English—when the subject is temporally limited to a sufficiently homogenous form—is synchronic focusing on understanding how a given stage in the history of English functions as a whole. The diachronic approach, by contrast, studies language change by comparing the different stages. The terms synchrony and diachrony are often associated with historical linguist Ferdinand de Saussure, who considered the synchronic perspective as systematic but argu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glacial Deposits
image:Geschiebemergel.JPG, Closeup of glacial till. Note that the larger grains (pebbles and gravel) in the till are completely surrounded by the matrix of finer material (silt and sand), and this characteristic, known as ''matrix support'', is diagnostic of till. image:Glacial till exposed in roadcut-750px.jpg, Glacial till with tufts of grass Till or glacial till is unsorted glacier, glacial sediment. Till is derived from the erosion and entrainment of material by the moving ice of a glacier. It is deposited some distance down-ice to form terminal, lateral, medial and ground moraines. Till is classified into primary deposits, laid down directly by glaciers, and secondary deposits, reworked by fluvial transport and other processes. Description Till is a form of ''glacial drift'', which is rock material transported by a glacier and deposited directly from the ice or from running water emerging from the ice. It is distinguished from other forms of drift in that it is deposi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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