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Brent Crater
The Brent crater is an impact crater in both the geographic township of Deacon, Unorganized South Nipissing District and the municipal township of Papineau-Cameron in Nipissing District, northeastern Ontario, Canada, located north of Cedar Lake in northern Algonquin Provincial Park. It is in diameter and the age is estimated to be ca. 453 million years (Ordovician). The crater can be reached using Brent Road, south of Ontario Highway 17. A sign, erected at the site by the Archeological and Historic Sites Board, Archives of Ontario, reads: The Brent Crater: First recognized in 1951 from aerial photographs, the crater is a circular depression about two miles in diameter formed in Precambrian crystalline rocks. Geophysical and diamond drilling investigations show that the crater has a present depth of about 1,400 feet but is partly filled with sedimentary rocks with a thickness of 900 feet. The rocks beneath the crater floor are thoroughly fragmented over a depth of 2,000 feet. Li ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Devonian
The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, where rocks from this period were first studied. The first significant adaptive radiation of life on dry land occurred during the Devonian. Free-sporing vascular plants began to spread across dry land, forming extensive forests which covered the continents. By the middle of the Devonian, several groups of plants had evolved leaves and true roots, and by the end of the period the first seed-bearing plants appeared. The arthropod groups of myriapods, arachnids and hexapods also became well-established early in this period, after starting their expansion to land at least from the Ordovician period. Fish reached substantial diversity during this time, leading the Devonian to often be dubbed the Age of Fishes. The placoderms began dominating ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Precambrian
The Precambrian (or Pre-Cambrian, sometimes abbreviated pꞒ, or Cryptozoic) is the earliest part of Earth's history, set before the current Phanerozoic Eon. The Precambrian is so named because it preceded the Cambrian, the first period of the Phanerozoic Eon, which is named after Cambria, the Latinised name for Wales, where rocks from this age were first studied. The Precambrian accounts for 88% of the Earth's geologic time. The Precambrian is an informal unit of geologic time, subdivided into three eons ( Hadean, Archean, Proterozoic) of the geologic time scale. It spans from the formation of Earth about 4.6 billion years ago ( Ga) to the beginning of the Cambrian Period, about million years ago ( Ma), when hard-shelled creatures first appeared in abundance. Overview Relatively little is known about the Precambrian, despite it making up roughly seven-eighths of the Earth's history, and what is known has largely been discovered from the 1960s onwards. The Precambrian fossil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ottawa-Bonnechere Graben
The Ottawa-Bonnechere Graben (also known as the Ottawa Graben) is a geological structure that coincides with a wide topographic depression extending from near Montréal through Ottawa. It is part of the Saint Lawrence rift system that also includes the seismically active Saguenay graben. This rift valley was formed when the Earth's crust moved downward about a kilometre between two major fault zones known as the Mattawa and Petawawa faults. Geography The Ottawa-Bonnechere Graben measures about , running from the Montreal area on the east to near Sudbury and Lake Nipissing on the west. On the east, it joins the Saint Lawrence rift system, a half-graben which extends more than 1000 km along the Saint Lawrence River valley and links the Ottawa and Saguenay Graben. The segment of the Ottawa-Bonnechere Graben west of Ottawa was the first to be recognized as a graben. Since then, it has been traced west to Lake Nipissing, and northwestwards from the confluence of the Mattawa a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glaciers
A glacier (; ) is a persistent body of dense ice that is constantly moving under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires distinguishing features, such as crevasses and seracs, as it slowly flows and deforms under stresses induced by its weight. As it moves, it abrades rock and debris from its substrate to create landforms such as cirques, moraines, or fjords. Although a glacier may flow into a body of water, it forms only on land and is distinct from the much thinner sea ice and lake ice that form on the surface of bodies of water. On Earth, 99% of glacial ice is contained within vast ice sheets (also known as "continental glaciers") in the polar regions, but glaciers may be found in mountain ranges on every continent other than the Australian mainland, including Oceania's high-latitude oceanic island countries such as New Zealand. Between latitudes 35°N and 35°S, glaciers occur only ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Limestone
Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms when these minerals precipitate out of water containing dissolved calcium. This can take place through both biological and nonbiological processes, though biological processes, such as the accumulation of corals and shells in the sea, have likely been more important for the last 540 million years. Limestone often contains fossils which provide scientists with information on ancient environments and on the evolution of life. About 20% to 25% of sedimentary rock is carbonate rock, and most of this is limestone. The remaining carbonate rock is mostly dolomite, a closely related rock, which contains a high percentage of the mineral dolomite, . ''Magnesian limestone'' is an obsolete and poorly-defined term used variously for dolomite, for limes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sediment
Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sand and silt can be carried in suspension in river water and on reaching the sea bed deposited by sedimentation; if buried, they may eventually become sandstone and siltstone (sedimentary rocks) through lithification. Sediments are most often transported by water (fluvial processes), but also wind (aeolian processes) and glaciers. Beach sands and river channel deposits are examples of fluvial transport and deposition, though sediment also often settles out of slow-moving or standing water in lakes and oceans. Desert sand dunes and loess are examples of aeolian transport and deposition. Glacial moraine deposits and till are ice-transported sediments. Classification Sediment can be classified based on its grain size, grain shape, and c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bicarbonate
In inorganic chemistry, bicarbonate (IUPAC-recommended nomenclature: hydrogencarbonate) is an intermediate form in the deprotonation of carbonic acid. It is a polyatomic anion with the chemical formula . Bicarbonate serves a crucial biochemical role in the physiological pH buffering system. The term "bicarbonate" was coined in 1814 by the English chemist William Hyde Wollaston. The name lives on as a trivial name. Chemical properties The bicarbonate ion (hydrogencarbonate ion) is an anion with the empirical formula and a molecular mass of 61.01 daltons; it consists of one central carbon atom surrounded by three oxygen atoms in a trigonal planar arrangement, with a hydrogen atom attached to one of the oxygens. It is isoelectronic with nitric acid . The bicarbonate ion carries a negative one formal charge and is an amphiprotic species which has both acidic and basic properties. It is both the conjugate base of carbonic acid ; and the conjugate acid of , ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acid
In computer science, ACID ( atomicity, consistency, isolation, durability) is a set of properties of database transactions intended to guarantee data validity despite errors, power failures, and other mishaps. In the context of databases, a sequence of database operations that satisfies the ACID properties (which can be perceived as a single logical operation on the data) is called a ''transaction''. For example, a transfer of funds from one bank account to another, even involving multiple changes such as debiting one account and crediting another, is a single transaction. In 1983, Andreas Reuter and Theo Härder coined the acronym ''ACID'', building on earlier work by Jim Gray who named atomicity, consistency, and durability, but not isolation, when characterizing the transaction concept. These four properties are the major guarantees of the transaction paradigm, which has influenced many aspects of development in database systems. According to Gray and Reuter, the IBM Informa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Algonquin Park
Algonquin Provincial Park is a provincial park located between Georgian Bay and the Ottawa River in Ontario, Canada, mostly within the Unorganized South Part of Nipissing District. Established in 1893, it is the oldest provincial park in Canada. Additions since its creation have increased the park to its current size of about . The park is contiguous with several smaller, administratively separate provincial parks that protect important rivers in the area, resulting in a larger total protected area. Its size, combined with its proximity to the major urban centres of Toronto and Ottawa, makes Algonquin one of the most popular provincial parks in the province and the country. Highway 60 runs through the south end of the park, while the Trans-Canada Highway bypasses it to the north. Over 2,400 lakes and 1,200 kilometres of streams and rivers are located within the park. Some notable examples include Canoe Lake and the Petawawa, Nipissing, Amable du Fond, Madawaska, and Tim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trinitrotoluene
Trinitrotoluene (), more commonly known as TNT, more specifically 2,4,6-trinitrotoluene, and by its preferred IUPAC name 2-methyl-1,3,5-trinitrobenzene, is a chemical compound with the formula C6H2(NO2)3CH3. TNT is occasionally used as a reagent in chemical synthesis, but it is best known as an explosive material with convenient handling properties. The explosive yield of TNT is considered to be the standard comparative convention of bombs and asteroid impacts. In chemistry, TNT is used to generate charge transfer salts. History TNT was first prepared in 1863 by German chemist Julius Wilbrand and originally used as a yellow dye. Its potential as an explosive was not recognized for three decades, mainly because it was too difficult to detonate because it was less sensitive than alternatives. Its explosive properties were first discovered in 1891 by another German chemist, Carl Häussermann. TNT can be safely poured when liquid into shell cases, and is so insensitive that i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meteorite
A meteorite is a solid piece of debris from an object, such as a comet, asteroid, or meteoroid, that originates in outer space and survives its passage through the atmosphere to reach the surface of a planet or Natural satellite, moon. When the original object enters the atmosphere, various factors such as friction, pressure, and chemical interactions with the atmospheric gases cause it to heat up and radiate energy. It then becomes a meteor and forms a Meteoroid#Fireball, fireball, also known as a shooting star; astronomers call the brightest examples "Bolide#Astronomy, bolides". Once it settles on the larger body's surface, the meteor becomes a meteorite. Meteorites vary greatly in size. For geologists, a bolide is a meteorite large enough to create an impact crater. Meteorites that are recovered after being observed as they transit the atmosphere and Impact event, impact the Earth are called meteorite falls. All others are known as meteorite finds. Meteorites have traditiona ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
New Quebec Crater
The Pingualuit Crater (french: Cratère des Pingualuit; from Inuit "pimple"), formerly called the "Chubb Crater" and later the "New Quebec Crater" (french: Cratère du Nouveau-Québec), is a relatively young impact crater located on the Ungava Peninsula in the administrative region of Nord-du-Québec, in Quebec, Canada. It is in diameter, and is estimated to be 1.4 ± 0.1 million years old (Pleistocene). The crater and the surrounding area are now part of Pingualuit National Park. The only species of fish in the impact crater lake, crater lake is the Arctic char. Geography The crater is exposed to the surface, rising above the surrounding tundra, and is deep. The Pingualuk Lake fills the hollow, and is one of the deepest lakes in North America. The lake also holds some of the purest fresh water in the world, with a salinity level of less than 3 ppm (by comparison, the salinity level of the Great Lakes is 500 ppm). It is one of the most transparent lakes in the world, with a Se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
