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Skyscraper Mountain (Alaska)
Skyscraper Mountain is a summit in Alaska, United States. Description Skyscraper Mountain is located 14 miles (22.5 km) northwest of Palmer, Alaska, in the Talkeetna Mountains, on land managed as the Hatcher Pass Management Area of the state park system. It is also immediately north of Hatcher Pass and southwest of the Independence Mine State Historic Park. Precipitation runoff from this mountain's east slope drains to the nearby Little Susitna River via Fishhook Creek, whereas the west side drains to the Susitna River via Willow Creek. Topographic relief is significant as the summit rises above Fishhook Creek in . Access is via the Palmer-Fishhook Road (also called Hatcher Pass Road), and a 2.2-mile trail (round-trip) gains 1,170 feet of elevation to reach the summit.Lisa Maloney, ''Day Hiking Southcentral Alaska'', Mountaineers Books, 2019, . The Martin Mine located on the mountain's northeast slope was the site of the first gold quartz discovery in the Willow Creek mi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bullion Mountain
Bullion Mountain is a summit in Alaska, United States. Description Bullion Mountain is located 14 miles (22.5 km) northwest of Palmer, Alaska, in the Talkeetna Mountains, on land managed as the Hatcher Pass Management Area of the state park system. It is also immediately west of the Independence Mine State Historic Park. Precipitation runoff from this mountain's east slope drains to the nearby Little Susitna River via Fishhook Creek, whereas the west side drains to the Susitna River via Willow Creek. Topographic relief is significant as the summit rises above the Independence Mines in . Access is via the Palmer-Fishhook Road (also called Hatcher Pass Road). This mountain's toponym has been officially adopted by the United States Board on Geographic Names as a local name reported in 1951 by U.S. Geological Survey.Donald J. Orth, ''Dictionary of Alaska Place Names'', U.S. Government Printing Office, 1967, p. 167. The Gold Bullion Mine located high on the northwest slope of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Board On Geographic Names
The United States Board on Geographic Names (BGN) is a Federal government of the United States, federal body operating under the United States Secretary of the Interior. The purpose of the board is to establish and maintain uniform usage of geography, geographic names throughout the federal government of the United States. History Following the American Civil War, more and more American pioneer, American settlers began moving westward, prompting the Federal government of the United States, U.S. federal government to pursue some sort of consistency for referencing landmarks on maps and in official documents. As such, on January 8, 1890, Thomas Corwin Mendenhall, superintendent of the United States Coast and Geodetic Survey Office, wrote to 10 noted geographers "to suggest the organization of a Board made up of representatives from the different Government services interested, to which may be referred any disputed question of geographical orthography." President Benjamin Harrison si ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geography Of Alaska
Alaska occupies the northwestern portion of the North American continent and is bordered only by Canada on the east. It is one of two U.S. states not bordered by another state; Hawaii is the other. Alaska has more ocean coastline than all of the other U.S. states combined. About of Canadian territory consisting of British Columbia (in Canada) separate Alaska from Washington U.S. state. Alaska is thus an exclave of the United States that is part of the continental U.S. and the U.S. West Coast, but is not part of the contiguous U.S. The state is bordered by Yukon and British Columbia, Canada to the east, the Gulf of Alaska and the Pacific Ocean to the south, Russia (Chukotka Autonomous Okrug), Bering Sea, the Bering Strait, and the Chukchi Sea to the west, and the Beaufort Sea and the Arctic Ocean to the north. Because it extends into the Eastern Hemisphere, it is technically both the westernmost and easternmost state in the United States, as well as also being the northernmo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subarctic Climate
The subarctic climate (also called subpolar climate, or boreal climate) is a continental climate with long, cold (often very cold) winters, and short, warm to cool summers. It is found on large landmasses, often away from the moderating effects of an ocean, generally at latitudes from 50°N to 70°N, poleward of the humid continental climates. Like other Class D climates, they are rare in the Southern Hemisphere, only found at some isolated highland elevations. Subarctic or boreal climates are the source regions for the cold air that affects temperate latitudes to the south in winter. These climates represent Köppen climate classification ''Dfc'', ''Dwc'', ''Dsc'', ''Dfd'', ''Dwd'' and ''Dsd''. Description This type of climate offers some of the most extreme seasonal temperature variations found on the planet: in winter, temperatures can drop to below and in summer, the temperature may exceed . However, the summers are short; no more than three months of the year (but at least on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Köppen Climate Classification
The Köppen climate classification divides Earth climates into five main climate groups, with each group being divided based on patterns of seasonal precipitation and temperature. The five main groups are ''A'' (tropical), ''B'' (arid), ''C'' (temperate), ''D'' (continental), and ''E'' (polar). Each group and subgroup is represented by a letter. All climates are assigned a main group (the first letter). All climates except for those in the ''E'' group are assigned a seasonal precipitation subgroup (the second letter). For example, ''Af'' indicates a tropical rainforest climate. The system assigns a temperature subgroup for all groups other than those in the ''A'' group, indicated by the third letter for climates in ''B'', ''C'', ''D'', and the second letter for climates in ''E''. Other examples include: ''Cfb'' indicating an oceanic climate with warm summers as indicated by the ending ''b.'', while ''Dwb'' indicates a semi-Monsoon continental climate, monsoonal continental climate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Schist
Schist ( ) is a medium-grained metamorphic rock generally derived from fine-grained sedimentary rock, like shale. It shows pronounced ''schistosity'' (named for the rock). This means that the rock is composed of mineral grains easily seen with a low-power hand lens, oriented in such a way that the rock is easily split into thin flakes or plates. This texture (geology), texture reflects a high content of platy minerals, such as mica, talc, chlorite group, chlorite, or graphite. These are often interleaved with more granular minerals, such as feldspar or quartz. Schist typically forms during regional metamorphism accompanying the process of mountain building (orogeny) and usually reflects a medium Metamorphism#Metamorphic grades, grade of metamorphism. Schist can form from many different kinds of rocks, including sedimentary rocks such as mudstones and igneous rocks such as tuffs. Schist metamorphosed from mudstone is particularly common and is often very rich in mica (a ''mica schis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monzonite
Monzonite is an igneous intrusive rock, formed by slow cooling of underground magma that has a moderate silica content and is enriched in alkali metal oxides. Monzonite is composed mostly of plagioclase and alkali feldspar. Syenodiorite is an obsolescent term for monzonite or for monzodiorite.Le Maitre, R.W., ''Igneous Rocks: A Classification and Glossary of Terms'' Cambridge University Press, 2nd ed, pp. 113 Larvikite is a particular form of monzonite. Description Monzonite is a coarse-grained ( phaneritic) igneous rock. Such rocks are classified by their relative percentages of quartz, plagioclase, alkali feldspar, and feldspathoid (the QAPF classification). Monzonite is defined as rock having less than 5% quartz in its QAPF fraction and in which alkali feldspar makes up between 35% and 65% of the total feldspar content. If quartz constitutes greater than 5% of the QAPF fraction, the rock is termed a quartz monzonite, while if feldspathoids are present as up to 10% of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quartz
Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The Atom, atoms are linked in a continuous framework of SiO4 silicon–oxygen Tetrahedral molecular geometry, tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical formula of Silicon dioxide, SiO2. Quartz is, therefore, classified structurally as a Silicate mineral#Tectosilicates, framework silicate mineral and compositionally as an oxide mineral. Quartz is the second most abundant mineral in Earth's continental crust, behind feldspar. Quartz exists in two forms, the normal α-quartz and the high-temperature β-quartz, both of which are chiral. The transformation from α-quartz to β-quartz takes place abruptly at . Since the transformation is accompanied by a significant change in volume, it can easily induce microfracturing of ceramics or rocks passing through this temperature threshold. There are many different varieties of quartz, several of which are classifi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Million Years Ago
Million years ago, abbreviated as Mya, Myr (megayear) or Ma (megaannum), is a unit of time equal to (i.e. years), or approximately 31.6 teraseconds. Usage Myr is in common use in fields such as Earth science and cosmology. Myr is also used with Mya or Ma. Together they make a reference system, one to a quantity, the other to a particular point in a year numbering system that is ''time before the present''. Myr is deprecated in geology, but in astronomy ''Myr'' is standard. Where "myr" ''is'' seen in geology, it is usually "Myr" (a unit of mega-years). In astronomy, it is usually "Myr" (Million years). Debate In geology, a debate remains open concerning the use of ''Myr'' (duration) plus ''Mya'' (million years ago) versus using only the term ''Ma''. In either case, the term '' Ma'' is used in geology literature conforming to ISO 31-1 (now ISO 80000-3) and NIST 811 recommended practices. Traditional style geology literature is written: The "ago" is implied, so that any s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tonalite
Tonalite is an igneous rock, igneous, plutonic (Intrusive rock, intrusive) rock (geology), rock, of felsic composition, with phaneritic (coarse-grained) texture. Feldspar is present as plagioclase (typically oligoclase or andesine) with alkali feldspar making up less than 10% of the total feldspar content. Quartz (SiO2) is present as more than 20% of the total quartz-alkali feldspar-plagioclase-feldspathoid (QAPF classification, QAPF) content of the rock. Amphiboles and biotite are common in lesser quantities, while accessory minerals include apatite, magnetite and zircon. In older references tonalite is sometimes used as a synonym for quartz diorite. However the current IUGS QAPF diagram, classification defines tonalite as having greater than 20% quartz, while quartz diorite varies its quartz content from 5 to 20%. The name is derived from the type locality of tonalites, adjacent to the Tonale Line, a major structural lineament and mountain pass, Tonale Pass, in the Italy, Itali ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Willow Creek Mining District
The Willow Creek mining district, also known as the Independence Mine/Hatcher Pass district, is a gold-mining area in the U.S. state of Alaska. Underground hard-rock mining of gold from quartz veins accounts for most of the mineral wealth extracted from the Hatcher Pass area. The first mining efforts were placer mining of stream gravels, and placer mining in the area has continued sporadically to this day. Robert Hatcher discovered gold and staked the first claim in the Willow Creek valley in September 1906. The first lode mill in the area started operating in 1908. Underground mining continued at a variety of locations around the pass until 1951. In the 1980s one of the area's hard-rock mines was briefly re-opened. At least one mining company is actively exploring for gold in the area now. Through 2006 the district produced 667-thousand ounces of hard rock gold and 60-thousand ounces of placer gold. The Willow Creek district at Hatcher Pass is historically the third-largest lode-go ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
