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Sawtooth Range (Idaho)
The Sawtooth Range is a mountain range of the Rocky Mountains in central Idaho, United States, reaching a maximum elevation of at the summit of Thompson Peak. It encompasses an area of spanning parts of Custer, Boise, Blaine, and Elmore counties, and is bordered to the east by the Sawtooth Valley. Much of the mountain range is within the Sawtooth Wilderness, part of the Sawtooth National Recreation Area and Sawtooth National Forest. The mountains were named for their jagged peaks. Peaks There are 57 peaks with an elevation over in the Sawtooth Range, all falling between on Thompson Peak, the highest point in the range. Another 77 peaks fall between . Climbs range in difficulty between the Observation Peak, a Class 1 hike, and King Spire, a rock route rated Class 5.10 on the Yosemite Decimal System. Geology The northern Sawtooth Range formed from the Eocene Sawtooth batholith, while south of Alturas Lake the mountains formed from the Cretaceous granodiorite of the Id ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States
The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 contiguous states border Canada to the north and Mexico to the south, with the semi-exclave of Alaska in the northwest and the archipelago of Hawaii in the Pacific Ocean. The United States asserts sovereignty over five Territories of the United States, major island territories and United States Minor Outlying Islands, various uninhabited islands in Oceania and the Caribbean. It is a megadiverse country, with the world's List of countries and dependencies by area, third-largest land area and List of countries and dependencies by population, third-largest population, exceeding 340 million. Its three Metropolitan statistical areas by population, largest metropolitan areas are New York metropolitan area, New York, Greater Los Angeles, Los Angel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Granodiorite
Granodiorite ( ) is a coarse-grained (phaneritic) intrusive igneous rock similar to granite, but containing more plagioclase feldspar than orthoclase feldspar. The term banatite is sometimes used informally for various rocks ranging from granite to diorite, including granodiorite. The term ''granodiorite'' was first used by George F. Becker, G. F. Becker (1893) to describe granitic rocks in the Sierra Nevada, United States. Composition According to the QAPF diagram, granodiorite has a greater than 20% quartz by volume, and between 65% and 90% of the feldspar is plagioclase. A greater amount of plagioclase would designate the rock as tonalite. Granodiorite is felsic to intermediate composition, intermediate in composition. It is the Intrusive rock, intrusive igneous equivalent of the extrusive igneous dacite. It contains a large amount of sodium (Na) and calcium (Ca) rich plagioclase, potassium feldspar, quartz, and minor amounts of muscovite mica as the lighter colored miner ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyramidal Peak
A pyramidal peak, sometimes called a glacial horn in extreme cases, is an angular, sharply pointed mountain peak which results from the cirque erosion due to multiple glaciers diverging from a central point. Pyramidal peaks are often examples of nunataks. Formation Glaciers, typically forming in drainages on the sides of a mountain, develop bowl-shaped depression (geology), basins called cirques (sometimes called 'corries' – from Scottish Gaelic [kʰəɾə] (a bowl) – or s). Cirque glaciers have rotational sliding that abrades the floor of the basin more than walls and that causes the bowl shape to form. As cirques are formed by glaciation in an alpine environment, the headwall and ridges between parallel glaciers called arêtes become more steep and defined. This occurs due to Frost wedging, freeze/thaw and mass wasting beneath the ice surface. It is widely held that a common cause for headwall steepening and extension headward is the crevasses known as bergschrund that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moraines
A moraine is any accumulation of unconsolidated debris ( regolith and rock), sometimes referred to as glacial till, that occurs in both currently and formerly glaciated regions, and that has been previously carried along by a glacier or ice sheet. It may consist of partly rounded particles ranging in size from boulders (in which case it is often referred to as boulder clay) down to gravel and sand, in a groundmass of finely-divided clayey material sometimes called glacial flour. Lateral moraines are those formed at the side of the ice flow, and terminal moraines are those formed at the foot, marking the maximum advance of the glacier. Other types of moraine include ground moraines (till-covered areas forming sheets on flat or irregular topography) and medial moraines (moraines formed where two glaciers meet). Etymology The word ''moraine'' is borrowed from French , which in turn is derived from the Savoyard Italian ('mound of earth'). in this case was derived from Proven ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glacial Lakes
A glacial lake is a body of water with origins from glacier activity. They are formed when a glacier erodes the land and then melts, filling the depression created by the glacier. Formation Near the end of the last glacial period, roughly 10,000 years ago, glaciers began to retreat. A retreating glacier often left behind large deposits of ice in hollows between drumlins or hills. As the ice age ended, these melted to create lakes. These lakes are often surrounded by drumlins, along with other evidence of the glacier such as moraines, eskers and erosional features such as striations and chatter marks. These lakes are clearly visible in aerial photos of landforms in regions that were glaciated during the last ice age. The formation and characteristics of glacial lakes vary between location and can be classified into glacial erosion lake, ice-blocked lake, moraine-dammed lake, other glacial lake, supraglacial lake, and subglacial lake. Glacial lakes and changing climate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Western Washington University
Western Washington University (WWU or Western) is a public university in Bellingham, Washington, United States. The northernmost university in the contiguous United States, WWU was founded in 1893 as the state-funded New Whatcom Normal School, succeeding a private school of teaching for women founded in 1886. The university adopted its present name in 1977. WWU offers bachelor degree, bachelor's and master degree, master's degrees and a few doctorates. , there were 14,747 students, 13,801 of whom were Undergraduate education, undergraduate students, and 664 full-time faculty. Its athletic teams are known as the Western Washington Vikings, Vikings, which compete in NCAA Division II, Division II of the National Collegiate Athletic Association. The main campus is located on 215 acres in Bellingham. WWU also operates a marine center in Anacortes, Washington, Anacortes and academic locations in Everett, Washington, Everett and the Olympic Peninsula, Olympic and Kitsap Peninsula, Kits ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geology (journal)
''Geology'' is a peer-reviewed publication of the Geological Society of America (GSA). GSA stated (in 2006) (ISSN 0091-7613) that it is the most widely read scientific journal in the field of earth science. It is published monthly, with each issue containing 20 or more articles. One of the goals of the journal is to provide a forum for shorter articles (four pages each) and less focus on purely academic research–type articles. According to the ''Journal Citation Reports'', the journal had a 2020 impact factor of 5.399. The journal is indexed in Scopus and SCImago The SCImago Journal Rank (SJR) indicator is a measure of the prestige of scholarly journals that accounts for both the number of citations received by a journal and the prestige of the journals where the citations come from. Etymology SCImag .... See also * List of scientific journals ** List of earth and atmospheric sciences journals References External links *Geology — Browse Issues [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Little Ice Age
The Little Ice Age (LIA) was a period of regional cooling, particularly pronounced in the North Atlantic region. It was not a true ice age of global extent. The term was introduced into scientific literature by François E. Matthes in 1939. Matthes described glaciers in the Sierra Nevada (U.S.), Sierra Nevada of California that he believed could not have survived the hypsithermal; his usage of "Little Ice Age" has been superseded by "Neoglaciation". The period has been conventionally defined as extending from the 16th to the 19th centuries, (noted in Grove 2004: 4). but some experts prefer an alternative time-span from about 1300 to about 1850. The NASA Earth Observatory notes three particularly cold intervals. One began about 1650, another about 1770, and the last in 1850, all of which were separated by intervals of slight warming. The Intergovernmental Panel on Climate Change IPCC Third Assessment Report, Third Assessment Report considered that the timing and the areas affecte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pleistocene
The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was finally confirmed in 2009 by the International Union of Geological Sciences, the cutoff of the Pleistocene and the preceding Pliocene was regarded as being 1.806 million years Before Present (BP). Publications from earlier years may use either definition of the period. The end of the Pleistocene corresponds with the end of the last glacial period and also with the end of the Paleolithic age used in archaeology. The name is a combination of Ancient Greek () 'most' and (; Latinized as ) 'new'. The aridification and cooling trends of the preceding Neogene were continued in the Pleistocene. The climate was strongly variable depending on the glacial cycle, oscillating between cold Glacial period, glacial periods and warmer Interglacial, int ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rock Glacier
Rock glaciers are distinctive geomorphological landforms that consist either of angular rock debris frozen in interstitial ice, former "true" glaciers overlain by a layer of talus, or something in between. Rock glaciers are normally found at high latitudes and/or elevations, and may extend outward and downslope from talus cones, glaciers or terminal moraines of glaciers. There are two types of rock glacier: periglacial glaciers (or talus-derived glaciers), and glacial rock glaciers, such as the Timpanogos Glacier in Utah, which are often found where glaciers once existed. Possible Martian rock glacier features have been identified by the Mars Reconnaissance Orbiter spacecraft. A rock glacier, especially if its origin is unclear, can be considered as a discrete debris accumulation. Rock avalanches can be misidentified as rock glaciers, or may evolve into them. Formation The two known factors that must be present in order to create rock glaciers are low ice velocity and per ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Snow Field
A snow field, snowfield or neve is an accumulation of permanent snow and ice, typically found above the snow line, normally in mountainous and glacial terrain. Glaciers A glacier (; or ) is a persistent body of dense ice, a form of rock, that is constantly moving downhill under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires ... originate in snowfields. The lower end of a glacier is usually free from snow and névé in summer. In the upper end and above the upper boundary of a glacier, the snow field is an ice field covered with snow. The glacier upper boundary, where it emerges from under a snow field, is ill-defined because of gradual transition.Thomas Chrowder Chamberlin, Rollin D. Salisbury (1904) "Geology"p. 258 References Bodies of ice Landforms {{glaciology-stub it:Formazioni nevose perenni#Nevaio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glaciation
A glacial period (alternatively glacial or glaciation) is an interval of time (thousands of years) within an ice age that is marked by colder temperatures and glacier advances. Interglacials, on the other hand, are periods of warmer climate between glacial periods. The Last Glacial Period ended about 15,000 years ago. The Holocene is the current interglacial. A time with no glaciers on Earth is considered a greenhouse climate state. Quaternary Period Within the Quaternary, which started about 2.6 million years before present, there have been a number of glacials and interglacials. At least eight glacial cycles have occurred in the last 740,000 years alone. Changes in atmospheric and associated radiative forcing were among the primary drivers of globally cold glacial and warm interglacial climates, with changes in ocean physical circulation, biological productivity and seawater acid-base chemistry likely causing most of the recorded changes Penultimate Glacial Period The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
