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Columbia River Basalt
The Columbia River Basalt Group is the youngest, smallest and one of the best-preserved continental flood basalt province on Earth, covering over mainly eastern Oregon and Washington, western Idaho, and part of northern Nevada. The basalt group includes the Steens and Picture Gorge basalt formations. Introduction During the middle to late Miocene epoch, the Columbia River flood basalts engulfed about of the Pacific Northwest, forming a large igneous province with an estimated volume of . Eruptions were most vigorous 17–14 million years ago, when over 99 percent of the basalt was released. Less extensive eruptions continued 14–6 million years ago. Erosion resulting from the Missoula Floods has extensively exposed these lava flows, laying bare many layers of the basalt flows at Wallula Gap, the lower Palouse River, the Columbia River Gorge and throughout the Channeled Scablands. The Columbia River Basalt Group is thought to be a potential link to the Chilc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Columbia River Flood-Basalt Province
Columbia may refer to: * Columbia (personification), the historical female national personification of the United States, and a poetic name for America Places North America Natural features * Columbia Plateau, a geologic and geographic region in the U.S. Pacific Northwest * Columbia River, in Canada and the United States ** Columbia Bar, a sandbar in the estuary of the Columbia River ** Columbia Country, the region of British Columbia encompassing the northern portion of that river's upper reaches ***Columbia Valley, a region within the Columbia Country ** Columbia Lake, a lake at the head of the Columbia River *** Columbia Wetlands, a protected area near Columbia Lake ** Columbia Slough, along the Columbia watercourse near Portland, Oregon * Glacial Lake Columbia, a proglacial lake in Washington state * Columbia Icefield, in the Canadian Rockies * Columbia Island (District of Columbia), in the Potomac River * Columbia Island (New York), in Long Island Sound Populated places * Co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chilcotin Group
The Chilcotin Group, also called the Chilcotin Plateau Basalts, is a large area of basaltic lava that forms a volcanic plateau running parallel with the Garibaldi Volcanic Belt in south-central British Columbia, Canada. Predominantly, during Miocene and Pliocene times, a medium-sized volcanic field of overlapping vents occurred in British Columbia's Interior Plateau. The distribution is assumed to engulf up to 50,000 km2 of the Pacific Northwest, forming a medium-sized large igneous province, of volume 3300 km3. Retrieved on 2012-09-22 Volcanism occurred as late as Oligocene time, but continues sporadically up to present. Eruptions were most vigorous 6- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Columbia River Plateau
The Columbia Plateau is a geologic and geographic region that lies across parts of the U.S. states of Washington, Oregon, and Idaho. It is a wide flood basalt plateau between the Cascade Range and the Rocky Mountains, cut through by the Columbia River. Geology During late Miocene and early Pliocene times, a flood basalt engulfed about of the Pacific Northwest, forming a large igneous province. Over a period of perhaps 10 to 15 million years, lava flow after lava flow poured out, ultimately accumulating to a thickness of more than 6,000 feet (1.8 km). As the molten rock came to the surface, the Earth's crust gradually sank into the space left by the rising lava. The Columbia River Basalt Group consists of seven formations: The Steens Basalt, Imnaha Basalt, Grande Ronde Basalt, Picture Gorge Basalt, Prineville Basalt, Wanapum Basalt, and Saddle Mountains Basalt. Many of these formations are subdivided into formal and informal members and flows. The subsidence of the crus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Siberian Traps
The Siberian Traps (russian: Сибирские траппы, Sibirskiye trappy) is a large region of volcanic rock, known as a large igneous province, in Siberia, Russia. The massive eruptive event that formed the trap rock, traps is one of the largest known Volcano, volcanic events in the last years. The eruptions continued for roughly two million years and spanned the Permian–Triassic boundary, or P–T boundary, which occurred around 251.9 million years ago. The Siberian Traps are believed to be the primary cause of the Permian–Triassic extinction event, the most severe extinction event in the geologic record."New Studies of Permian Extinction Shed Light On the Great Dying" New York Times, April 30, 2012. Retrieved ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
China
China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and borders fourteen countries by land, the most of any country in the world, tied with Russia. Covering an area of approximately , it is the world's third largest country by total land area. The country consists of 22 provinces, five autonomous regions, four municipalities, and two Special Administrative Regions (Hong Kong and Macau). The national capital is Beijing, and the most populous city and financial center is Shanghai. Modern Chinese trace their origins to a cradle of civilization in the fertile basin of the Yellow River in the North China Plain. The semi-legendary Xia dynasty in the 21st century BCE and the well-attested Shang and Zhou dynasties developed a bureaucratic political system to serve hereditary monarchies, or dyna ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Permian
The Permian ( ) is a geologic period and stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last period of the Paleozoic Era; the following Triassic Period belongs to the Mesozoic Era. The concept of the Permian was introduced in 1841 by geologist Sir Roderick Murchison, who named it after the region of Perm in Russia. The Permian witnessed the diversification of the two groups of amniotes, the synapsids and the sauropsids ( reptiles). The world at the time was dominated by the supercontinent Pangaea, which had formed due to the collision of Euramerica and Gondwana during the Carboniferous. Pangaea was surrounded by the superocean Panthalassa. The Carboniferous rainforest collapse left behind vast regions of desert within the continental interior. Amniotes, which could better cope with these drier conditions, rose to dominance in place of their am ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Emeishan Traps
The Emeishan Traps constitute a flood basalt volcanic province, or large igneous province, in south-western China, centred in Sichuan province. It is sometimes referred to as the Permian Emeishan Large Igneous Province or Emeishan Flood Basalts. Like other volcanic provinces or "trap rock, traps", the Emeishan Traps are multiple layers of igneous rock laid down by large mantle plume volcanic eruptions. The Emeishan Traps eruptions were serious enough to have global ecological and paleontological impact. It is named for Mount Emei, Emeishan, a mountain in Sichuan. Etymology The term "Trap rock, trap" has been used in geology since 1785–1795 for such rock formations. It is derived from the Swedish word for stairs ("trappa") and refers to the step-like hills forming the landscape of the region. Formation and development The eruptions that produced the Emeishan Traps began 265 million years ago (Ma) or earlier. The main eruptive period is between 262 and 261 Ma, and the volcan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
India
India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the south, the Arabian Sea on the southwest, and the Bay of Bengal on the southeast, it shares land borders with Pakistan to the west; China, Nepal, and Bhutan to the north; and Bangladesh and Myanmar to the east. In the Indian Ocean, India is in the vicinity of Sri Lanka and the Maldives; its Andaman and Nicobar Islands share a maritime border with Thailand, Myanmar, and Indonesia. Modern humans arrived on the Indian subcontinent from Africa no later than 55,000 years ago., "Y-Chromosome and Mt-DNA data support the colonization of South Asia by modern humans originating in Africa. ... Coalescence dates for most non-European populations average to between 73–55 ka.", "Modern human beings—''Homo sapiens''—originated in Africa. Then, int ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cretaceous Period
The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of the entire Phanerozoic. The name is derived from the Latin ''creta'', "chalk", which is abundant in the latter half of the period. It is usually abbreviated K, for its German translation ''Kreide''. The Cretaceous was a period with a relatively warm climate, resulting in high eustatic sea levels that created numerous shallow inland seas. These oceans and seas were populated with now-extinct marine reptiles, ammonites, and rudists, while dinosaurs continued to dominate on land. The world was ice free, and forests extended to the poles. During this time, new groups of mammals and birds appeared. During the Early Cretaceous, flowering plants appeared and began to rapidly diversify, becoming the dominant group of plants across the Earth by t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deccan Traps
The Deccan Traps is a large igneous province of west-central India (17–24°N, 73–74°E). It is one of the largest volcanic features on Earth, taking the form of a large shield volcano. It consists of numerous layers of solidified flood basalt that together are more than about thick, cover an area of about , and have a volume of about . Originally, the Deccan Traps may have covered about ,"What really killed the dinosaurs?" Jennifer Chu, MIT News Office, 11 December 2014 with a correspondingly larger original volume. This volume overlies the age |
K–Ar Dating
Potassium–argon dating, abbreviated K–Ar dating, is a radiometric dating method used in geochronology and archaeology. It is based on measurement of the product of the radioactive decay of an isotope of potassium (K) into argon (Ar). Potassium is a common element found in many materials, such as feldspars, micas, clay minerals, tephra, and evaporites. In these materials, the decay product is able to escape the liquid (molten) rock, but starts to accumulate when the rock solidifies ( recrystallizes). The amount of argon sublimation that occurs is a function of the purity of the sample, the composition of the mother material, and a number of other factors. These factors introduce error limits on the upper and lower bounds of dating, so that the final determination of age is reliant on the environmental factors during formation, melting, and exposure to decreased pressure or open air. Time since recrystallization is calculated by measuring the ratio of the amount of accumulated to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radiometric Dating
Radiometric dating, radioactive dating or radioisotope dating is a technique which is used to date materials such as rocks or carbon, in which trace radioactive impurities were selectively incorporated when they were formed. The method compares the abundance of a naturally occurring radioactive isotope within the material to the abundance of its decay products, which form at a known constant rate of decay. The use of radiometric dating was first published in 1907 by Bertram Boltwood and is now the principal source of information about the absolute age of rocks and other geological features, including the age of fossilized life forms or the age of Earth itself, and can also be used to date a wide range of natural and man-made materials. Together with stratigraphic principles, radiometric dating methods are used in geochronology to establish the geologic time scale. Among the best-known techniques are radiocarbon dating, potassium–argon dating and uranium–lead dating. By al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
