1.
Summit
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A summit is a point on a surface that is higher in elevation than all points immediately adjacent to it. Mathematically, a summit is a maximum in elevation. The topographic terms acme, apex, peak, and zenith are synonymous, the UIAA definition is that a summit is independent if it has a prominence of 30 metres or more, it is a mountain if it has a prominence of at least 300 metres. This can be summarised as follows, A pyramidal peak is an exaggerated form produced by ice erosion of a mountain top, Summit may also refer to the highest point along a line, trail, or route. In many parts of the western United States, the term refers to the highest point along a road, highway. For example, the highest point along Interstate 80 in California is referred to as Donner Summit while the highest point on Interstate 5 is Siskiyou Mountain Summit, geoid Hill List of highest mountains Maxima and minima Nadir Summit accordance Peak finder
2.
Orogeny
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An Orogeny is an event that leads to a large structural deformation of the Earths lithosphere due to the interaction between tectonic plates. Orogens or orogenic belts develop when a plate is crumpled and is pushed upwards to form mountain ranges. Orogeny is the mechanism by which mountains are built on continents. The word orogeny comes from Ancient Greek, though it was used before him, the term was employed by the American geologist G. K. Gilbert in 1890 to describe the process of mountain building as distinguished from epeirogeny. Formation of an orogen is accomplished in part by the processes of subduction or convergence of two or more continents. Orogeny usually produces long arcuate structures, known as orogenic belts, generally, orogenic belts consist of long parallel strips of rock exhibiting similar characteristics along the length of the belt. Orogenic belts are associated with zones, which consume crust, produce volcanoes. Geologists attribute the arcuate structure to the rigidity of the descending plate and these island arcs may be added to a continent during an orogenic event. The processes of orogeny can take tens of millions of years, frequently, rock formations that undergo orogeny are severely deformed and undergo metamorphism. Orogenic processes may push deeply buried rocks to the surface, sea-bottom and near-shore material may cover some or all of the orogenic area. If the orogeny is due to two continents colliding, very high mountains can result, an orogenic event may be studied, as a tectonic structural event, as a geographical event, and as a chronological event. The foreland basin forms ahead of the orogen due mainly to loading and resulting flexure of the lithosphere by the mountain belt. The basin migrates with the front and early deposited foreland basin sediments become progressively involved in folding and thrusting. Sediments deposited in the basin are mainly derived from the erosion of the actively uplifting rocks of the mountain range. The fill of many such shows an change in time from deepwater marine through shallow water to continental sediments. Although orogeny involves plate tectonics, the tectonic forces result in a variety of associated phenomena, including magmatism, metamorphism, crustal melting, what exactly happens in a specific orogen depends upon the strength and rheology of the continental lithosphere, and how these properties change during orogenesis. In addition to orogeny, the orogen is subject to other processes, for example, the Caledonian Orogeny refers to the Silurian and Devonian events that resulted from the collision of Laurentia with Eastern Avalonia and other former fragments of Gondwana. The Caledonian Orogen resulted from events and various others that are part of its peculiar orogenic cycle
3.
Cambrian
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The Cambrian Period was the first geological period of the Paleozoic Era, of the Phanerozoic Eon. The Cambrian lasted 55.6 million years from the end of the preceding Ediacaran Period 541 million years ago to the beginning of the Ordovician Period 485.4 mya and its subdivisions, and its base, are somewhat in flux. The period was established by Adam Sedgwick, who named it after Cambria, the Latinised form of Cymru, the Welsh name for Wales, as a result, our understanding of the Cambrian biology surpasses that of some later periods. The rapid diversification of lifeforms in the Cambrian, known as the Cambrian explosion, most of the continents were probably dry and rocky due to a lack of vegetation. Shallow seas flanked the margins of several continents created during the breakup of the supercontinent Pannotia, the seas were relatively warm, and polar ice was absent for much of the period. The United States Federal Geographic Data Committee uses a barred capital C ⟨Є⟩ character similar to the capital letter Ukrainian Ye ⟨Є⟩ to represent the Cambrian Period, the proper Unicode character is U+A792 Ꞓ LATIN CAPITAL LETTER C WITH BAR. Despite the long recognition of its distinction from younger Ordovician Period rocks and older Supereon Precambrian rocks, the base of the Cambrian lies atop a complex assemblage of trace fossils known as the Treptichnus pedum assemblage. Pedum in Namibia, Spain and Newfoundland, and possibly, in the western USA, the stratigraphic range of T. pedum overlaps the range of the Ediacaran fossils in Namibia, and probably in Spain. The Cambrian Period followed the Ediacaran Period and was followed by the Ordovician Period, the Cambrian is divided into four epochs and ten ages. Currently only two series and five stages are named and have a GSSP, because the international stratigraphic subdivision is not yet complete, many local subdivisions are still widely used. In some of these subdivisions the Cambrian is divided into three epochs with locally differing names – the Early Cambrian, Middle Cambrian and Furongian, rocks of these epochs are referred to as belonging to the Lower, Middle, or Upper Cambrian. Trilobite zones allow biostratigraphic correlation in the Cambrian, each of the local epochs is divided into several stages. The International Commission on Stratigraphy list the Cambrian period as beginning at 541 million years ago, the lower boundary of the Cambrian was originally held to represent the first appearance of complex life, represented by trilobites. The recognition of small shelly fossils before the first trilobites, and Ediacara biota substantially earlier and this formal designation allowed radiometric dates to be obtained from samples across the globe that corresponded to the base of the Cambrian. Early dates of 570 million years ago quickly gained favour, though the used to obtain this number are now considered to be unsuitable. A more precise date using modern radiometric dating yield a date of 541 ±0.3 million years ago, most continental land was clustered in the Southern Hemisphere at this time, but was drifting north. Large, high-velocity rotational movement of Gondwana appears to have occurred in the Early Cambrian, the sea levels fluctuated somewhat, suggesting there were ice ages, associated with pulses of expansion and contraction of a south polar ice cap. In Baltoscandia a Lower Cambrian transgression transformed large swathes of the Sub-Cambrian peneplain into a epicontinental sea, the Earth was generally cold during the early Cambrian, probably due to the ancient continent of Gondwana covering the South Pole and cutting off polar ocean currents
4.
Granite
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Granite is a common type of felsic intrusive igneous rock that is granular and phaneritic in texture. Granites can be white, pink, or gray in color. The word granite comes from the Latin granum, a grain, in reference to the structure of such a holocrystalline rock. By definition, granite is a rock with at least 20% quartz. The term granitic means granite-like and is applied to granite and a group of igneous rocks with similar textures and slight variations in composition. Occasionally some individual crystals are larger than the groundmass, in case the texture is known as porphyritic. A granitic rock with a texture is known as a granite porphyry. Granitoid is a general, descriptive field term for lighter-colored, coarse-grained igneous rocks, petrographic examination is required for identification of specific types of granitoids. The extrusive igneous rock equivalent of granite is rhyolite, Granite is nearly always massive, hard and tough, and therefore it has gained widespread use throughout human history, and more recently as a construction stone. The average density of granite is between 2.65 and 2.75 g/cm3, its compressive strength usually lies above 200 MPa, and its viscosity near STP is 3–6 •1019 Pa·s. The melting temperature of dry granite at ambient pressure is 1215–1260 °C, it is reduced in the presence of water. Granite has poor primary permeability, but strong secondary permeability, true granite according to modern petrologic convention contains both plagioclase and alkali feldspars. When a granitoid is devoid or nearly devoid of plagioclase, the rock is referred to as alkali feldspar granite, when a granitoid contains less than 10% orthoclase, it is called tonalite, pyroxene and amphibole are common in tonalite. A granite containing both muscovite and biotite micas is called a binary or two-mica granite, two-mica granites are typically high in potassium and low in plagioclase, and are usually S-type granites or A-type granites. A worldwide average of the composition of granite, by weight percent, based on 2485 analyses. Much of it was intruded during the Precambrian age, it is the most abundant basement rock that underlies the relatively thin veneer of the continents. Outcrops of granite tend to form tors and rounded massifs, granites sometimes occur in circular depressions surrounded by a range of hills, formed by the metamorphic aureole or hornfels. Granite often occurs as small, less than 100 km² stock masses
5.
Gabbro
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Gabbro refers to a large group of dark, often phaneritic, mafic intrusive igneous rocks chemically equivalent to basalt. It forms when magma is trapped beneath the Earths surface. Much of the Earths oceanic crust is made of gabbro, formed at mid-ocean ridges, Gabbro is also found as plutons associated with continental volcanism. Due to its variant nature, the term gabbro may be applied loosely to a range of intrusive rocks. The term gabbro was used in the 1760s to name a set of types that were found in the ophiolites of the Apennine Mountains in Italy. Then, in 1809, the German geologist Christian Leopold von Buch used the term more restrictively in his description of these Italian ophiolitic rocks and he assigned the name gabbro to rocks that geologists nowadays would more strictly call metagabbro. Von Buch named gabbro after Gabbro, a village in Rosignano Marittimo municipality of Tuscany, Gabbro is dense, greenish or dark-colored and contains pyroxene, plagioclase, and minor amounts of amphibole and olivine. The pyroxene content is mostly clinopyroxene, generally augite, but small amounts of orthopyroxene may also be present, if the amount of orthopyroxene is more than 95% of the total pyroxene content, then the rock is termed norite. On the other hand, gabbro has more than 95% of its pyroxenes in the form of the monoclinic clinopyroxene/s, the calcium rich plagioclase feldspar and pyroxene content vary between 10% - 90% in gabbro. If more than 90% plagioclase is present, then the rock is an anorthosite, if on the other hand, the rock contains more than 90% pyroxenes, it is termed pyroxenite. Gabbro may also contain amounts of olivine, amphibole and biotite. The quartz content in gabbro is less than 5% of total volume, quartz gabbros or monzogabbros are also known to occur, for example the cizlakite at Pohorje in northeastern Slovenia, and are probably derived from magma that was over-saturated with silica. Gabbros contain minor amounts, typically a few percent, of iron-titanium oxides such as magnetite, ilmenite, Gabbro is generally coarse grained, with crystals in the size range of 1 mm or greater. Finer grained equivalents of gabbro are called diabase, although the term microgabbro is often used when extra descriptiveness is desired, Gabbro may be extremely coarse grained to pegmatitic, and some pyroxene-plagioclase cumulates are essentially coarse grained gabbro, some may exhibit acicular crystal habits. Gabbro is usually equigranular in texture, although it may be porphyritic at times, cumulate gabbros are more properly termed pyroxene-plagioclase adcumulate. Gabbro is an part of the oceanic crust, and can be found in many ophiolite complexes as parts of zones III. Long belts of gabbroic intrusions are typically formed at proto-rift zones and around ancient rift zone margins, mantle plume hypotheses may rely on identifying mafic and ultramafic intrusions and coeval basalt volcanism. It is better to base a rock definition on descriptive characteristics of the rather than how or where it was formed
6.
Conglomerate (geology)
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Conglomerates form by the consolidation and lithification of gravel. The size and composition of the fraction of a conglomerate may or may not vary in composition, sorting. In some conglomerates, the gravel-size class consist almost entirely of what were clay clasts at the time of deposition, conglomerates can be found in sedimentary rock sequences of all ages but probably make up less than 1 percent by weight of all sedimentary rocks. A sedimentary rock composed largely of gravel is first named according to the roundness of the gravel, if the gravel clasts that comprise it is largely well-rounded to subrounded, it is a conglomerate. If the gravel clasts that comprise it are largely angular, it is a breccia, such breccias can be called sedimentary breccias to differentiate them from other types of breccia, e. g. volcanic and fault breccias. Sedimentary rocks that contain a mixture of rounded and angular gravel clasts are sometimes called breccio-conglomerate, conglomerates are rarely composed entirely of gravel-size clasts. Typically, the space between the gravel-size clasts is filled by a mixture composed of varying amounts of silt, sand, paraconglomerates are also often unstratified and can contain more matrix than gravel clasts. If the gravel clasts of a conglomerate are in contact with each other, unlike paraconglomerates, orthoconglomerates are typically cross-bedded and often well-cemented and lithified by either calcite, hematite, quartz, or clay. The differences between paraconglomerates and orthoconglomerates reflect differences in how they are deposited, paraconglomerates are commonly either glacial tills or debris flow deposits. Orthoconglomerates are typically associated with aqueous currents, conglomerates are also classified according to the composition of their clasts. A conglomerate or any clastic sedimentary rock that consists of a rock or mineral is known as either a monomict, monomictic, oligomict. If the conglomerate consists of two or more different types of rocks, minerals, or combination of both, it is known as either a polymict or polymictic conglomerate. If a polymictic conglomerate contains an assortment of the clasts of metastable and unstable rocks and minerals, two recognized types of type of intraformational conglomerates are shale-pebble and flat-pebble conglomerates. Finally, conglomerates are often differentiated and named according to the dominant clast size comprising them, conglomerates are deposited in a variety of sedimentary environments. In turbidites, the part of a bed is typically coarse-grained. In this setting, conglomerates are normally very well sorted, well-rounded, conglomerates are normally present at the base of sequences laid down during marine transgressions above an unconformity, and are known as basal conglomerates. They represent the position of the shoreline at a time and are diachronous. Conglomerates deposited in environments are typically well rounded and well sorted
7.
Oklahoma
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Oklahoma is a state located in the South Central United States. Oklahoma is the 20th-most extensive and the 28th-most populous of the 50 United States, the states name is derived from the Choctaw words okla and humma, meaning red people. The name was settled upon statehood, Oklahoma Territory and Indian Territory were merged, on November 16,1907, Oklahoma became the 46th state to enter the union. Its residents are known as Oklahomans, or informally Okies, and its capital, a major producer of natural gas, oil, and agricultural products, Oklahoma relies on an economic base of aviation, energy, telecommunications, and biotechnology. In 2007, it had one of the economies in the United States, ranking among the top states in per capita income growth. Oklahoma City and Tulsa serve as Oklahomas primary economic anchors, with nearly two-thirds of Oklahomans living within their metropolitan statistical areas. With small mountain ranges, prairie, mesas, and eastern forests, most of Oklahoma lies in the Great Plains, Cross Timbers, interior Highlands—a region especially prone to severe weather. The name Oklahoma comes from the Choctaw phrase okla humma, literally meaning red people, equivalent to the English word Indian, okla humma was a phrase in the Choctaw language used to describe Native American people as a whole. Oklahoma later became the de facto name for Oklahoma Territory, and it was approved in 1890. Oklahoma is the 20th-largest state in the United States, covering an area of 69,898 square miles and it is one of six states on the Frontier Strip and lies partly in the Great Plains near the geographical center of the 48 contiguous states. It is bounded on the east by Arkansas and Missouri, on the north by Kansas, on the northwest by Colorado, on the far west by New Mexico, much of its border with Texas lies along the Southern Oklahoma Aulacogen, a failed continental rift. The geologic figure defines the placement of the Red River, the Oklahoma panhandles Western edge is out of alignment with its Texas border. The Oklahoma/New Mexico border is actually 2.1 to 2.2 miles east of the Texas line, the border between Texas and New Mexico was set first as a result of a survey by Spain in 1819. It was then set along the 103rd Meridian, in the 1890s, when Oklahoma was formally surveyed using more accurate surveying equipment and techniques, it was discovered the Texas line was not set along the 103rd Meridian. Surveying techniques were not as accurate in 1819, and the actual 103rd Meridian was approximately 2.2 miles to the east and it was much easier to leave the mistake than for Texas to cede land to New Mexico to correct the surveying error. The placement of the Oklahoma/New Mexico border represents the true 103rd Meridian, cimarron County in Oklahomas panhandle is the only county in the United States that touches four other states, New Mexico, Texas, Colorado and Kansas. Its highest and lowest points follow this trend, with its highest peak, Black Mesa, at 4,973 feet above sea level, situated near its far northwest corner in the Oklahoma Panhandle. The states lowest point is on the Little River near its far southeastern boundary near the town of Idabel, Oklahoma, which dips to 289 feet above sea level
8.
Fort Sill
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Fort Sill, Oklahoma is a United States Army post north of Lawton, Oklahoma, about 85 miles southwest of Oklahoma City. Today, Fort Sill remains the only active Army installation of all the forts on the Southern Plains built during the Indian Wars, Fort Sill is also one of the four locations for Army Basic Combat Training. It has played a significant role in every major American conflict since 1869, sheridans massive winter campaign involved six cavalry regiments accompanied by frontier scouts such as Buffalo Bill Cody, Wild Bill Hickok, Ben Clark and Jack Stilwell. At first, the garrison was called Camp Wichita and was referred to by the Indians as the Soldier House at Medicine Bluffs. Sheridan later named it in honor of his West Point classmate and friend, Brigadier General Joshua W. Sill, the first post commander was Brevet Maj. Gen. Benjamin Grierson and the first Indian agent was Colonel Albert Gallatin Boone, grandson of Daniel Boone. Fort Sill soldiers were restricted from taking action against the Indians. The Indians resumed raiding the Texas frontier and used Fort Sill as a sanctuary, in 1871, General of the Army William Tecumseh Sherman arrived at Fort Sill from Fort Richardson, Texas, while on a tour of Army posts throughout the country. Sherman was at Fort Richardson when they became aware of the Warren Wagon Train Raid, soon after Sherman arrived at Fort Sill, the Indian Agent brought several Kiowa chiefs to tell their story about attacking the wagon train. When Sherman ordered their arrest during a meeting on Griersons porch, in memory of the event, the Commanding Generals quarters were dubbed Sherman House. The Army arrested three chiefs during the skirmish, Satank, Satanta and Addo-etta. Sherman ordered them to Texas for a trial for the murders. When the three were put into a wagon and taken under escort to Fort Richardson, Satank began his death song. A mile down the trail, he grabbed the carbine of one of the troopers in the wagon, before he could cock and fire it, he was hit by several shots fired by the escort. Satank was left against a tree and the continued on its mission. A marker on Berry Road near the curve marks the spot where Satank and his grave is in Chiefs Knoll in the post cemetery. Satanta and Addo-etta were tried by Texas courts on 5 and 6 July and they were sentenced to death by hanging. Supporters of the Quaker peace policy convinced Governor Edmund J. Davis to commute the Indians sentences to life imprisonment, then in October 1873 they were paroled. In June 1874, the Comanches, Kiowas and Southern Cheyennes engaged in the Red River War, lasting a year, it was a war of attrition involving relentless pursuit by converging military columns
9.
Lawton, Oklahoma
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The city of Lawton is the county seat of Comanche County, in the State of Oklahoma. Located in southwestern Oklahoma, about 87 mi southwest of Oklahoma City, it is the city of the Lawton. According to the 2010 census, Lawtons population was 96,867, Lawtons landscape is typical of the Great Plains, with flat topography and gently rolling hills, while the area north of the city is marked by the Wichita Mountains. The citys proximity to Fort Sill Military Reservation gave Lawton economic, although Lawtons economy is still largely dependent on Fort Sill, it has also grown to encompass manufacturing, higher education, health care, and retail. The citys government is run by a government consisting of a city manager. Interstate 44 and three major United States highways serve the city, while Lawton-Fort Sill Regional Airport connects Lawton by air, recreation can be found at the citys many parks, lakes, museums, and festivals. Notable residents of the city include many musical and literary artists, the land that is present-day Oklahoma was first settled by prehistoric American Indians including the Clovis 11500 BCE, Folsom 10600 BCE and Plainview 10000 BCE cultures. Historic indigenous peoples who inhabited the region included the Wichita and Caddo peoples, in the 16th century, Spanish explorer Francisco Vásquez de Coronado visited in 1541, beginning European contact. Around the 1700s, two tribes from the north, the Comanches and Kiowas, migrated to the Oklahoma and Texas region, for most of the 18th century, the Oklahoma region was under nominal French control as Louisiana. The limited interaction between the peoples was based on fur trading, in 1803, the Louisiana Purchase by Thomas Jefferson brought the area under United States control. In 1830, Congress passed the Indian Removal Act, which removed American Indian tribes from the Southeast, the southern part of this territory was originally assigned to the Choctaw and Chickasaw. In 1867, the United States used the Medicine Lodge Treaty to allot the southwest portion of the Choctaw and Chickasaw’s lands to the Comanche, Kiowa, and Apache tribes. Fort Sill was established in 1869 after the American Civil War by Major General Philip Sheridan, in 1874, the Red River War broke out in the region when the Comanche, Kiowa, and Southern Cheyenne left their Indian Territory reservation. Attrition and skirmishes by the US Army finally forced the return of the back to Indian Territory in June 1875. In 1891, the United States Congress appointed a commission to meet with the tribal leaders, under other legislation, the United States through the Dawes Commission allotted communal lands as plots to individual households of tribal members, selling off what remained as surplus. These actions extinguished the claims to communal lands, a condition needed for the admission of Oklahoma as a state in 1907. After these changes, the legislature of the new began to organize counties. Three 320-acre sites in Kiowa, Caddo and Comanche counties were selected for county seats, the town was named for Major General Henry W. Lawton, a quartermaster at Fort Sill, who had taken part in the pursuit and capture of Geronimo
10.
Bison
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Bison are large, even-toed ungulates in the genus Bison within the subfamily Bovinae. Two extant and four species are recognized. Of the four species, three were North American endemics, Bison antiquus, B. latifrons, and B. occidentalis. The fourth, B. priscus, ranged across steppe environments from Western Europe, through Central Asia, East Asia including Japan, of the two surviving species, the American bison, B. bison, found only in North America, is the more numerous. Although sometimes referred to historically as a buffalo, it is distantly related to the true buffalo. The North American species is composed of two subspecies, the Plains bison, B. b. bison, and the Wood bison, B. b. athabascae, which is the namesake of Wood Buffalo National Park in Canada. A third subspecies, the Eastern Woodland Bison is no longer considered a valid taxon, references to Woods Bison or Wood Bison from the eastern United States confusingly refer to this subspecies, not B. b. athabascae, which was not found in the region. The European bison B. bonasus, or wisent, is found in Europe, while all bison species are classified in their own genus, they are sometimes bred with domestic cattle and produce fertile offspring called beefalo or zubron. The American bison and the European bison are the largest surviving terrestrial animals in North America, Bison are good swimmers and can cross rivers over half a mile wide. They are nomadic grazers and travel in herds, the bulls leave the herds of females at two or three years of age, and join a male herd, which are generally smaller than female herds. Towards the end of the summer, for the reproductive season, American bison are known for living in the Great Plains, but formerly had a much larger range including much of the eastern United States and parts of Mexico. The American Plains bison is no longer listed as endangered, genetically pure B. b. bison currently number only ~20,000, separated into fragmented herds - all of which require active conservation measures. Although superficially similar, physical and behavioural differences exist between the American and European bison, the American species has 15 ribs, while the European bison has 14. The American bison has four lumbar vertebrae, while the European has five, adult American bison are less slim in build and have shorter legs. American bison tend to more, and browse less than their European relatives. Their anatomies reflect this difference, the American bisons head hangs lower than the Europeans. The body of the American bison is hairier, though its tail has less hair than that of the European bison. American bison are more easily tamed than their European cousins, the bovine tribe split about 5 to 10 million years ago into the buffalos and a group leading to bison and taurine cattle
11.
Altus, Oklahoma
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Altus is a city and county seat in Jackson County, Oklahoma, United States. The population was 19,813 at the 2010 census, a loss of 7.7 percent compared to 21,454 at the 2000 census, Altus is home to Altus Air Force Base, the United States Air Force training base for C-17, KC-46 and KC-135 aircrews. It is also home to Western Oklahoma State College and Southwest Technology Center, the town that would later be named Altus was founded in 1886. The community was originally called Frazer, a settlement of about 50 people on Bitter Creek that served as a trading post on the Great Western Trail, cowboys driving herds northward often stopped to buy buttermilk from John McClearan. Thus, the town was known locally as Buttermilk Station, the Frazer post office opened February 18,1886. A flash flood nearly destroyed Frazer on June 4,1891, the residents moved to higher ground 2.5 miles east of the original site. W. R. Baucum suggested renaming the town Altus, a Latin word meaning high and this name stuck, although the town was also known as Leger from July 10,1901, to May 14,1904, The city has seen relatively steady growth since the beginning. The population doubled between the time of Oklahoma statehood and the 1910 census and even increased during the Great Depression, although Altus had been designated as the Jackson county seat at the time of statehood, an election was held in 1908 to determine the permanent seat. The two towns contending were Altus and Olustee, Altus won by a vote of 2,077 to 1,365. The county courthouse was there in 1910. An irrigation project in the 1940s and World War II led to growth in the town as the nearby air field was used to train military pilots. It was later purchased by the Missouri-Kansas-Texas Railroad and since 1991 is operated by the Wichita, Tillman, in 1908, the Kansas City, Mexico and Orient Railway built a line through Altus. Around the same time, the Altus, Wichita Falls and Hollis Railway constructed a line from Altus to the Oklahoma-Texas border, the railroads stimulated economic growth in the area and made Altus a regional agricultural center. By 1930, Altus had eight cotton gins, two cotton compresses, and eighteen wholesale businesses, Altus is located at 34°38′38″N 99°19′36″W. Altus is situated in what used to be Old Greer County, the city lies between the main channel and north fork of the Red River. According to the United States Census Bureau, the city has an area of 17.0 square miles. Altus has a subtropical climate bordering upon a semi-arid climate. Summers are very hot to sweltering, though heavy rainfall does occur due to remains of Gulf of Mexico hurricanes moving inland
12.
Igneous rock
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Igneous rock, or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rock is formed through the cooling and solidification of magma or lava, the magma can be derived from partial melts of existing rocks in either a planets mantle or crust. Typically, the melting is caused by one or more of three processes, an increase in temperature, a decrease in pressure, or a change in composition, solidification into rock occurs either below the surface as intrusive rocks or on the surface as extrusive rocks. Igneous rock may form with crystallization to form granular, crystalline rocks, Igneous and metamorphic rocks make up 90–95% of the top 16 km of the Earths crust by volume. Igneous rocks form about 15% of the Earths current land surface, most of the Earths oceanic crust is made of igneous rock. In terms of modes of occurrence, igneous rocks can be either intrusive or extrusive, the mineral grains in such rocks can generally be identified with the naked eye. Intrusive rocks can also be classified according to the shape and size of the intrusive body, typical intrusive formations are batholiths, stocks, laccoliths, sills and dikes. When the magma solidifies within the earths crust, it cools slowly forming coarse textured rocks, such as granite, gabbro, the central cores of major mountain ranges consist of intrusive igneous rocks, usually granite. When exposed by erosion, these cores may occupy huge areas of the Earths surface, intrusive igneous rocks that form at depth within the crust are termed plutonic rocks and are usually coarse-grained. Intrusive igneous rocks that form near the surface are termed subvolcanic or hypabyssal rocks, hypabyssal rocks are less common than plutonic or volcanic rocks and often form dikes, sills, laccoliths, lopoliths, or phacoliths. Extrusive igneous rocks, also known as rocks, are formed at the crusts surface as a result of the partial melting of rocks within the mantle. Extrusive igneous rocks cool and solidify quicker than intrusive igneous rocks and they are formed by the cooling of molten magma on the earths surface. The magma, which is brought to the surface through fissures or volcanic eruptions, hence such rocks are smooth, crystalline and fine-grained. Basalt is an extrusive igneous rock and forms lava flows, lava sheets. Some kinds of basalt solidify to form long polygonal columns, the Giants Causeway in Antrim, Northern Ireland is an example. The molten rock, with or without suspended crystals and gas bubbles, is called magma and it rises because it is less dense than the rock from which it was created. When magma reaches the surface from beneath water or air, it is called lava, eruptions of volcanoes into air are termed subaerial, whereas those occurring underneath the ocean are termed submarine. Black smokers and mid-ocean ridge basalt are examples of volcanic activity
