The Farallon Plate was an ancient oceanic plate that began subducting under the west coast of the North American Plate—then located in modern Utah—as Pangaea broke apart during the Jurassic period. It is named for the Farallon Islands, which are located just west of San Francisco, over time, the central part of the Farallon Plate was completely subducted under the southwestern part of the North American Plate. These fragments from elsewhere are called terranes, much of western North America is composed of these accreted terranes. The understanding of the Farallon Plate is rapidly evolving as details from seismic tomography provide improved details of the submerged remnants, since the North American west coast shows a convoluted structure, significant work has been required to resolve the complexity. In 2013 a new and more nuanced explanation emerged, proposing two additional now-subducted plates which would account for some of the complexity. As data accumulated, a view developed that one large oceanic plate, the Farallon plate, acted as a conveyor belt, conveying terranes to North Americas west coast.
As the continent overran the subducting Farallon plate, the plate became subducted into the mantle below the continent. When the plates converged, the oceanic plate sank into the mantle to form a slab below the lighter continent. However this simple model was unable to explain many terrane complexities, one such large slab wall runs from north-west Canada to the eastern U. S. and extends to Central America, this slab wall had traditionally been associated with the subducting Farallon plate. Sigloch and Mihalynuk proposed that the Farallon should be partitioned into Northern Farallon, Mezcalera, the overridden segment is replaced by an incipient South Farallon trench. 160–155 Myr ago the Rocky Mountain deformation begins, recorded by a synorogenic clastic wedge, the Franciscan subduction complex on the South Farallon plate begins. 125 Myr ago the collision of the North America margin with an archipelago of terranes begins and this broad expanse causes strong deformations and creates the Sevier Mountains and the Canadian Rocky Mountains.
124–90 Myr ago the Omenica magmatic belts are formed in the Pacific Northwest along with a gradual override of the Mezcalera promontory by the Pacific Northwest,85 Myr ago the South Farallon trench moves westward after accretion of the Shatsky Rise Conjugate plateau. Sonora volcanism results from the slab sinking, the Tarahumara ignimbrite province is formed. 85–55 Myr ago Strong transpressive coupling of Farallon plate to terranes produces the buoyant Shatsky Rise, the Laramide orogeny results from basement uplift more than 1,000 km inland. 72–69 Myr ago the Angayucham arc, is overridden by North America, northward shuffle of Insular terrane, Intermontane terrane, and Angayucham terranes along margin. 55–50 Myr ago saw the override of the Cascadia Root arc by the Pacific Northwest along with accretion of the Siletzia and Pacific Rim terranes
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 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 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
Nature reserves may be designated by government institutions in some countries, or by private landowners, such as charities and research institutions, regardless of nationality. Nature reserves fall into different IUCN categories depending on the level of protection afforded by local laws, early reservations often had a religious underpinning, such as the evil forest areas of West Africa which were forbidden to humans, who were threatened with spiritual attack if they went there. Sacred areas taboo from human entry to fishing and hunting are known by ancient cultures worldwide. The worlds first modern nature reserve was established in 1821 by the naturalist and explorer Charles Waterton around his estate in Walton Hall and he spent £9000 on the construction of a 3 mile long,9 ft tall wall to enclose his park from poachers. He tried to encourage birdlife by planting trees and hollowing out trunks for owls to nest in and he invented artificial nest boxes to house starlings and sand martins and unsuccessfully attempted to introduce little owls from Italy.
Drachenfels was protected as the first state-designated nature reserve in modern-day Germany, in Australia, a nature reserve is the title of a type of protected area used in the jurisdictions of the Australian Capital Territory, New South Wales and Western Australia. The term “nature reserve” is defined in the relevant statutes used in those states and territories rather than by a national statute. As of 2014,1767 out of a total of 10339 protected areas listed within the Australian National Reserve System used the term “nature reserve in their names, in Brazil, nature reserves are classified as ecological stations or biological reserves by the National System of Conservation Units. Their main objectives are preserving fauna and flora and other natural attributes, visits are allowed only with permission, and only for educational or scientific purposes. Changes to the ecosystems in both types of reserve are allowed to restore and preserve the balance, biological diversity. Ecological stations are allowed to change the environment within strictly defined limits for the purpose of scientific research.
A wildlife reserve in Brazil is protected, and hunting is not allowed, there are 30 nature reserves in Egypt which cover 12% of Egyptian land. Those nature reserves were built according to the laws no, 102/1983 and 4/1994 for protection of the Egyptian nature reserve. Egypt announced a plan from to build 40 nature reserves from 1997 to 2017, to protect the natural resources. The largest nature reserve in Egypt is Gebel Elba in the southeast, denmark has three national parks and several nature reserves, some of them inside the national park areas. The largest single reserve is Hanstholm Nature Reserve, which covers 40 km2 and is part of Thy National Park, in Sweden there are 29 national parks. The first of them were established in 1909, in fact, Sweden was the first European country that established 9 national parks. There are almost 4,000 nature reserves in Sweden and they comprise about 85% of the surface that is protected by the Swedish Enironmental Code
National Park Service
It was created on August 25,1916, by Congress through the National Park Service Organic Act and is an agency of the United States Department of the Interior. As of 2014, the NPS employs 21,651 employees who oversee 417 units, the National Park Service celebrated its centennial in 2016. National parks and national monuments in the United States were originally individually managed under the auspices of the Department of the Interior, the movement for an independent agency to oversee these federal lands was spearheaded by business magnate and conservationist Stephen Mather, as well as J. Horace McFarland. With the help of journalist Robert Sterling Yard, Mather ran a publicity campaign for the Department of the Interior and they wrote numerous articles that praised the scenic and historic qualities of the parks and their possibilities for educational and recreational benefits. This campaign resulted in the creation of a National Park Service, Mather became the first director of the newly formed NPS.
On March 3,1933, President Herbert Hoover signed the Reorganization Act of 1933, the act would allow the President to reorganize the executive branch of the United States government. It wasnt until that summer when the new President, Franklin D. Roosevelt, President Roosevelt agreed and issued two Executive orders to make it happen. In 1951, Conrad Wirth became director of the National Park Service, the demand for parks after the end of the World War II had left the parks overburdened with demands that could not be met. In 1952, with the support of President Dwight D. Eisenhower, he began Mission 66, New parks were added to preserve unique resources and existing park facilities were upgraded and expanded. In 1966, as the Park Service turned 50 years old, emphasis began to turn from just saving great and wonderful scenery, Director George Hartzog began the process with the creation of the National Lakeshores and National Recreation Areas. Since its inception in 1916, the National Park Service has managed each of the United States national parks, Yellowstone National Park was the first national park in the United States.
In 1872, there was no government to manage it. Yosemite National Park began as a park, the land for the park was donated by the federal government to the state of California in 1864 for perpetual conservation. Yosemite was returned to federal ownership, at first, each national park was managed independently, with varying degrees of success. In Yellowstone, the staff was replaced by the U. S. Army in 1886. Due to the irregularities in managing these national treasures, Stephen Mather petitioned the government to improve the situation. In response, Secretary of the Interior Franklin K. Lane challenged him to lobby for creating a new agency, Mather was successful with the ratification of the National Park Service Organic Act in 1916. Later, the agency was given authority over other protected areas, the National Park System includes all properties managed by the National Park Service
Joshua Tree National Park
Joshua Tree National Park is located in southeastern California. Declared a U. S. National Park in 1994 when the U. S. Congress passed the California Desert Protection Act and it is named for the Joshua trees native to the park. It covers a area of 790,636 acres —an area slightly larger than the state of Rhode Island. A large part of the park, some 429,690 acres, is a wilderness area. The Little San Bernardino Mountains run through the southwest edge of the park, in 1950, the size of the park was reduced by about 265,000 acres to exclude some mining property. The park was elevated to a National Park on 31 October 1994 by the Desert Protection Act, the higher and cooler Mojave Desert is the special habitat of Yucca brevifolia, the Joshua tree for which the park is named. It occurs in patterns from dense forests to distantly spaced specimens, in addition to Joshua tree forests, the western part of the park includes some of the most interesting geologic displays found in Californias deserts. The dominant geologic features of landscape are hills of bare rock.
These hills are popular amongst rock climbing and scrambling enthusiasts, the flatland between these hills is sparsely forested with Joshua trees. Together with the piles and Skull Rock, the trees make the landscape otherworldly. Temperatures are most comfortable in the spring and fall, with an average high/low of 85 and 50 °F respectively, winter brings cooler days, around 60 °F, and freezing nights. It occasionally snows at higher elevations, summers are hot, over 100 °F during the day and not cooling much below 75 °F until the early hours of the morning. Joshua trees dominate the open spaces of the park, but in among the outcroppings are piñon pine, California juniper, Quercus turbinella, Quercus john-tuckeri. These communities are under stress, however, as the climate was wetter until the 1930s, with the same hot. These cycles were nothing new, but the vegetation did not prosper when wetter cycles returned. The difference may have been human development, cattle grazing took out some of the natural cover and made it less resistant to the changes.
But the bigger problem seems to be invasive species, such as cheatgrass, in drier times, they die back, but do not quickly decompose. This makes wildfires hotter and more destructive, which some of the trees that would have otherwise survived
The Parker Valley is located along the Lower Colorado River within the Lower Colorado River Valley region, in southwestern Arizona and southeastern California. Its natural habitats are within the Sonoran Desert and Colorado Desert ecoregions, riparian zone habitats on the river include Mesquite Bosques. The river has supported irrigated agricultural conversion of the valleys landscape, three major drainages of the Colorado River enter in the Parker Valley region. The Bill Williams River and Bouse Wash have confluences with the Colorado in the valley area. Tyson Wash crosses the La Posa Plain and enters downstream, with its watershed east of the river in the Colorado River Indian Reservation, in California, the Vidal Valley and the Whipple Mountains border the Parker Valley on the northwest, and the Palo Verde Valley on the southwest. In Arizona the Buckskin Mountains border the valley on the north, settlements within Parker Valley include and Poston in Arizona, and Earp and Big River in California.
It is at the area of the Colorado River Indian Reservation on the Colorado River. Valleys of the Lower Colorado River Valley U. S. Geological Survey Geographic Names Information System, Parker Valley Arizona Atlas & Gazetteer, DeLorme, c
California is the most populous state in the United States and the third most extensive by area. Located on the western coast of the U. S, California is bordered by the other U. S. states of Oregon and Arizona and shares an international border with the Mexican state of Baja California. Los Angeles is Californias most populous city, and the second largest after New York City. The Los Angeles Area and the San Francisco Bay Area are the nations second- and fifth-most populous urban regions, California has the nations most populous county, Los Angeles County, and its largest county by area, San Bernardino County. The Central Valley, an agricultural area, dominates the states center. What is now California was first settled by various Native American tribes before being explored by a number of European expeditions during the 16th and 17th centuries, the Spanish Empire claimed it as part of Alta California in their New Spain colony. The area became a part of Mexico in 1821 following its war for independence.
The western portion of Alta California was organized as the State of California, the California Gold Rush starting in 1848 led to dramatic social and demographic changes, with large-scale emigration from the east and abroad with an accompanying economic boom. If it were a country, California would be the 6th largest economy in the world, fifty-eight percent of the states economy is centered on finance, real estate services and professional, scientific and technical business services. Although it accounts for only 1.5 percent of the states economy, the story of Calafia is recorded in a 1510 work The Adventures of Esplandián, written as a sequel to Amadis de Gaula by Spanish adventure writer Garci Rodríguez de Montalvo. The kingdom of Queen Calafia, according to Montalvo, was said to be a land inhabited by griffins and other strange beasts. This conventional wisdom that California was an island, with maps drawn to reflect this belief, shortened forms of the states name include CA, Cal. Calif. and US-CA.
Settled by successive waves of arrivals during the last 10,000 years, various estimates of the native population range from 100,000 to 300,000. The Indigenous peoples of California included more than 70 distinct groups of Native Americans, ranging from large, settled populations living on the coast to groups in the interior. California groups were diverse in their organization with bands, villages. Trade and military alliances fostered many social and economic relationships among the diverse groups, the first European effort to explore the coast as far north as the Russian River was a Spanish sailing expedition, led by Portuguese captain Juan Rodríguez Cabrillo, in 1542. Some 37 years English explorer Francis Drake explored and claimed a portion of the California coast in 1579. Spanish traders made unintended visits with the Manila galleons on their trips from the Philippines beginning in 1565
In physical geography, a dune is a hill of loose sand built by wind or the flow of water. Dunes occur in different shapes and sizes, formed by interaction with the flow of air or water, most kinds of dunes are longer on the windward side where the sand is pushed up the dune and have a shorter slip face in the lee of the wind. The valley or trough between dunes is called a slack, a dune field is an area covered by extensive sand dunes. Dunes occur, for example, in deserts and along some coasts. Some coastal areas have one or more sets of dunes running parallel to the shoreline directly inland from the beach, in most cases, the dunes are important in protecting the land against potential ravages by storm waves from the sea. Although the most widely distributed dunes are those associated with coastal regions, Dunes can form under the action of water flow, and on sand or gravel beds of rivers and the sea-bed. The modern word dune came into English from French c,1790, which in turn came from Middle Dutch dūne.
Crescent-shaped mounds are generally wider than they are long, the slipfaces are on the concave sides of the dunes. These dunes form under winds that blow consistently from one direction, some types of crescentic dunes move more quickly over desert surfaces than any other type of dune. A group of dunes moved more than 100 metres per year between 1954 and 1959 in Chinas Ningxia Province, and similar speeds have been recorded in the Western Desert of Egypt. The largest crescentic dunes on Earth, with mean crest-to-crest widths of more than three kilometres, are in Chinas Taklamakan Desert. They may be composed of clay, sand, or gypsum, eroded from the floor or shore, transported up the concave side of the dune. Examples in Australia are up to 6.5 km long,1 km wide and they occur in southern and West Africa, and in parts of the western United States, especially Texas. Straight or slightly sinuous sand ridges typically much longer than they are wide are known as linear dunes and they may be more than 160 kilometres long.
Some linear dunes merge to form Y-shaped compound dunes, many form in bidirectional wind regimes. The long axes of these dunes extend in the resultant direction of sand movement, linear loess hills known as pahas are superficially similar. These hills appear to have formed during the last ice age under permafrost conditions dominated by sparse tundra vegetation. Radially symmetrical, star dunes are pyramidal sand mounds with slipfaces on three or more arms that radiate from the center of the mound
Traditional definitions require a topographic map to show both natural and man-made features. A topographic map is published as a map series, made up of two or more map sheets that combine to form the whole map. A contour line is a line connecting places of equal elevation, however, in the vernacular and day to day world, the representation of relief is popularly held to define the genre, such that even small-scale maps showing relief are commonly called topographic. The study or discipline of topography is a broader field of study. Topographic maps are based on topographical surveys, performed at large scales, these surveys are called topographical in the old sense of topography, showing a variety of elevations and landforms. This is in contrast to older cadastral surveys, which primarily show property, the first multi-sheet topographic map series of an entire country, the Carte géométrique de la France, was completed in 1789. Topographic surveys were prepared by the military to assist in planning for battle, as such, elevation information was of vital importance.
As they evolved, topographic map series became a resource in modern nations in planning infrastructure. Excluding borders, each sheet was 44 cm high and up to 66 cm wide, although the project eventually foundered, it left an indexing system that remains in use. TIGER was developed in the 1980s and used in the 1990, digital elevation models were compiled, initially from topographic maps and stereographic interpretation of aerial photographs and from satellite photography and radar data. Since all these were government projects funded with taxes and not classified for security reasons. Initial applications were mostly professionalized forms such as innovative surveying instruments, by the mid-1990s, increasingly user-friendly resources such as online mapping in two and three dimensions, integration of GPS with mobile phones and automotive navigation systems appeared. As of 2011, the future of standardized, centrally printed topographical maps is left somewhat in doubt, the various features shown on the map are represented by conventional signs or symbols.
For example, colors can be used to indicate a classification of roads and these signs are usually explained in the margin of the map, or on a separately published characteristic sheet. Topographic maps are commonly called contour maps or topo maps. In the United States, where the national series is organized by a strict 7. 5-minute grid. Topographic maps conventionally show topography, or land contours, by means of contour lines, contour lines are curves that connect contiguous points of the same altitude. In other words, every point on the line of 100 m elevation is 100 m above mean sea level
Geology of the Grand Canyon area
The geology of the Grand Canyon area includes one of the most complete and studied sequences of rock on Earth. The nearly 40 major sedimentary rock exposed in the Grand Canyon. Most were deposited in warm, shallow seas and near ancient, both marine and terrestrial sediments are represented, including fossilized sand dunes from an extinct desert. There are at least 14 known unconformities in the record found in the Grand Canyon. Uplift of the region started about 75 million years ago during the Laramide orogeny, in total, the Colorado Plateau was uplifted an estimated 2 miles. The adjacent Basin and Range Province to the west started to form about 18 million years ago as the result of crustal stretching, a drainage system that flowed through what is today the eastern Grand Canyon emptied into the now lower Basin and Range province. Opening of the Gulf of California around 6 million years ago enabled a large river to cut its way northeast from the gulf, the new river captured the older drainage to form the ancestral Colorado River, which in turn started to form the Grand Canyon.
Wetter climates brought upon by ice ages starting 2 million years ago greatly increased excavation of the Grand Canyon, volcanic activity deposited lava over the area 1.8 million to 500,000 years ago. At least 13 lava dams blocked the Colorado River, forming lakes that were up to 2,000 feet deep, the end of the last ice age and subsequent human activity has greatly reduced the ability of the Colorado River to excavate the canyon. Dams in particular have upset patterns of sediment transport and deposition, controlled floods from Glen Canyon Dam upstream have been conducted to see if they have a restorative effect. Earthquakes and mass wasting erosive events still affect the region, at about 2.5 and 1.8 billion years ago in Precambrian time, mud and ash were laid down in a marine basin adjacent to an orogenic belt. From 1.8 to 1.6 billion years ago at least two island arcs collided with the proto-North American continent and this process of plate tectonics compressed and grafted the marine sediments in the basin onto the mainland and uplifted them out of the sea.
Later, these rocks were buried 12 miles under the surface and this is the resistant rock now exposed at the bottom of the canyon in the Inner Gorge. As the volcanic islands collided with the mainland around 1.7 billion years ago, blobs of magma rose from the subduction zone and these plutons slowly cooled to form the Zoroaster Granite, part of which would be metamorphosed into gneiss. This rock unit can be seen as light-colored bands in the darker garnet-studded Vishnu Schist, the intrusion of the granite occurred in three phases, two during the initial Vishnu metamorphism period, and a third around 1.4 billion years ago. The third phase was accompanied by faulting, particularly along north—south faults. The collision expanded the continent from the Wyoming–Colorado border into Mexico, part of this thickening created the 5-to-6-mile high ancestral Mazatzal Mountains. Subsequent erosion lasting 300 million years stripped much of the exposed sediments and this reduced the very high mountains to small hills a few tens to hundreds of feet high
Escobaria vivipara is a species of cactus known by several common names, including spinystar, and viviparous foxtail cactus. It is native to North America, where certain varieties can be found from Mexico to Canada, most are limited to the Mojave and Sonoran Deserts. This is a cactus growing to a maximum height of about 15 centimeters, often remaining smaller. It is densely covered in a mat of star-shaped arrays of straight white spines one to two and a half centimeters long and it flowers in yellow, pink, or purple blooms two to five centimeters across. Elephant Tree, Bursera microphylla, GlobalTwitcher. com, ed. N. Stromberg Jepson Manual, university of California, Berkeley U. S. Department of Agriculture. USDA, Escobaria vivipara Jepson Manual Treatment of Escobaria vivipara USDA Plants Profile for Escobaria vivipara Escobaria vivipara — U. C