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Hatcher Pass
Hatcher Pass (3,886 ft or 1,148 m) is a mountain pass through the southwest part of the Talkeetna Mountains, Alaska. It is named after Robert Hatcher, a prospector and miner. The nearest cities are Palmer, Alaska, Palmer and Wasilla, Alaska, Wasilla approximately to the south, and Willow, Alaska, Willow approximately to the west. The communities are at an elevation of approximately in the Matanuska-Susitna Valley, Mat-Su valley. Overview From the west, the pass is reached from the Parks Highway by a road winding approximately up the valley of Willow Creek. The pass divides the alpine headwaters of Willow Creek on the west from Fishhook Creek and the Independence Bowl on the east side. To the east the road drops into and follows the Little Susitna River canyon downstream, and south, some dozen miles to the abrupt mountain front at the edge of the broad Matanuska-Susitna Valley. The road is unpaved and minimally maintained for about over the pass. This central port ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hatcher Pass
Hatcher Pass (3,886 ft or 1,148 m) is a mountain pass through the southwest part of the Talkeetna Mountains, Alaska. It is named after Robert Hatcher, a prospector and miner. The nearest cities are Palmer, Alaska, Palmer and Wasilla, Alaska, Wasilla approximately to the south, and Willow, Alaska, Willow approximately to the west. The communities are at an elevation of approximately in the Matanuska-Susitna Valley, Mat-Su valley. Overview From the west, the pass is reached from the Parks Highway by a road winding approximately up the valley of Willow Creek. The pass divides the alpine headwaters of Willow Creek on the west from Fishhook Creek and the Independence Bowl on the east side. To the east the road drops into and follows the Little Susitna River canyon downstream, and south, some dozen miles to the abrupt mountain front at the edge of the broad Matanuska-Susitna Valley. The road is unpaved and minimally maintained for about over the pass. This central port ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Matanuska-Susitna Borough, Alaska
Matanuska-Susitna Borough (often referred to as the Mat-Su Borough) is a borough located in the U.S. state of Alaska. Its county seat is Palmer, and the largest community is the census-designated place of Knik-Fairview. The borough is part of the Anchorage Metropolitan Statistical Area, along with the municipality of Anchorage on its south. The Mat-Su Borough is so designated because it contains the entire Matanuska and Susitna Rivers. They empty into Cook Inlet, which is the southern border of the Mat-Su Borough. It is one of the few agricultural areas of Alaska. Geography The borough seat is Palmer, and the largest community is the census-designated place of Knik-Fairview, Alaska. As of the 2020 census, the population was 107,081, up from 88,995 in 2010. It is the fastest growing subdivision in Alaska. According to the U.S. Census Bureau, the borough has a total area of , of which is land and (2.6%) is water. Adjacent boroughs and census areas * Denali Borough, ... [...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] |
Earthquakes
An earthquake (also known as a quake, tremor or temblor) is the shaking of the surface of the Earth resulting from a sudden release of energy in the Earth's lithosphere that creates seismic waves. Earthquakes can range in intensity, from those that are so weak that they cannot be felt, to those violent enough to propel objects and people into the air, damage critical infrastructure, and wreak destruction across entire cities. The seismic activity of an area is the frequency, type, and size of earthquakes experienced over a particular time period. The seismicity at a particular location in the Earth is the average rate of seismic energy release per unit volume. The word ''tremor'' is also used for non-earthquake seismic rumbling. At the Earth's surface, earthquakes manifest themselves by shaking and displacing or disrupting the ground. When the epicenter of a large earthquake is located offshore, the seabed may be displaced sufficiently to cause a tsunami. Earthquakes ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tectonic
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 found ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Castle Mountain Fault
A castle is a type of fortified structure built during the Middle Ages predominantly by the nobility or royalty and by military orders. Scholars debate the scope of the word ''castle'', but usually consider it to be the private fortified residence of a lord or noble. This is distinct from a palace, which is not fortified; from a fortress, which was not always a residence for royalty or nobility; from a ''pleasance'' which was a walled-in residence for nobility, but not adequately fortified; and from a fortified settlement, which was a public defence – though there are many similarities among these types of construction. Use of the term has varied over time and has also been applied to structures such as hill forts and 19th-20th century homes built to resemble castles. Over the approximately 900 years when genuine castles were built, they took on a great many forms with many different features, although some, such as curtain walls, arrowslits, and portcullises, were ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arkose
Arkose () or arkosic sandstone is a detrital sedimentary rock, specifically a type of sandstone containing at least 25% feldspar. Arkosic sand is sand that is similarly rich in feldspar, and thus the potential precursor of arkose. Quartz is commonly the dominant mineral component, and some mica is often present. Apart from the mineral content, rock fragments may also be a significant component. Arkose usually contains small amounts of calcite cement, which causes it to effervesce (fizz) slightly in dilute hydrochloric acid; sometimes the cement also contains iron oxide. Arkose is typically grey to reddish in colour. The sand grains making up an arkose may range from fine to very coarse, but tend toward the coarser end of the scale. Fossils are rare in arkose, due to the depositional processes that form it, although bedding is frequently visible. Arkose is generally formed from the weathering of feldspar-rich igneous or metamorphic, most commonly granitic, rocks, which are p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tertiary
Tertiary ( ) is a widely used but obsolete term for the geologic period from 66 million to 2.6 million years ago. The period began with the demise of the non-avian dinosaurs in the Cretaceous–Paleogene extinction event, at the start of the Cenozoic Era, and extended to the beginning of the Quaternary glaciation at the end of the Pliocene Epoch. The time span covered by the Tertiary has no exact equivalent in the current geologic time system, but it is essentially the merged Paleogene and Neogene periods, which are informally called the Early Tertiary and the Late Tertiary, respectively. The Tertiary established the Antarctic as an icy island continent. Historical use of the term The term Tertiary was first used by Giovanni Arduino during the mid-18th century. He classified geologic time into primitive (or primary), secondary, and tertiary periods based on observations of geology in Northern Italy. Later a fourth period, the Quaternary, was applied. In the early d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deformation (engineering)
In engineering, deformation refers to the change in size or shape of an object. ''Displacements'' are the ''absolute'' change in position of a point on the object. Deflection is the relative change in external displacements on an object. Strain is the ''relative'' internal change in shape of an infinitesimally small cube of material and can be expressed as a non-dimensional change in length or angle of distortion of the cube. Strains are related to the forces acting on the cube, which are known as stress, by a stress-strain curve. The relationship between stress and strain is generally linear and reversible up until the yield point and the deformation is elastic. The linear relationship for a material is known as Young's modulus. Above the yield point, some degree of permanent distortion remains after unloading and is termed plastic deformation. The determination of the stress and strain throughout a solid object is given by the field of strength of materials and for a structure ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metamorphosed
Metamorphic rocks arise from the transformation of existing rock to new types of rock in a process called metamorphism. The original rock (protolith) is subjected to temperatures greater than and, often, elevated pressure of or more, causing profound physical or chemical changes. During this process, the rock remains mostly in the solid state, but gradually recrystallizes to a new texture or mineral composition. The protolith may be an igneous, sedimentary, or existing metamorphic rock. Metamorphic rocks make up a large part of the Earth's crust and form 12% of the Earth's land surface. They are classified by their protolith, their chemical and mineral makeup, and their texture. They may be formed simply by being deeply buried beneath the Earth's surface, where they are subject to high temperatures and the great pressure of the rock layers above. They can also form from tectonic processes such as continental collisions, which cause horizontal pressure, friction, and distorti ... [...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 the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quartz
Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical formula of SiO2. 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 classified as gemstones. Since antiquity, varieties of quartz have been the most commonly used minerals in the making of jewelry and hardstone carvings, especially in Eurasia. Quartz is the mineral defining the val ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
