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Natural Wonders

Natural Wonders
natural-wonders
Nature is a grand sculptor. It has made many magnificent features both by erosional and deposition features that could compete with the man-made ones . Here are some of them and description about their formation.Even while naming a few there are many in the process of formation.

DEVIL'S TOWER
                                                                                                                                            

Devils Tower National Monument
IUCN Category III (Natural Monument)
Devils Tower Darton 1900.jpg
Devils Tower, 1900
LocationCrook County, WyomingUSA
Nearest cityHulett, Wyoming


Area1,346.91 acres (5.45 km2)
EstablishedSeptember 24, 1906
Visitors386,558 (in 2004)
Governing bodyNational Park Service


Introduction

Devils Tower  is a monolithic igneous intrusion or volcanic neck located in theBlack Hills near Hulett and Sundance in Crook County, northeastern Wyoming, above the Belle Fourche River. It rises dramatically 1,267 feet (386 m) above the surrounding terrain and the summit is 5,112 feet (1,558 m) above sea level.

Devils Tower was the first declared United States National Monument, established on September 24, 1906, by President Theodore Roosevelt. The Monument's boundary encloses an area of 1,347 acres (5.45 km2).

In recent years about 1% of the Monument's 400,000 annual visitors climb Devils Tower, mostly through traditional climbing techniques.


Geological history
Devils Tower in geological context. The oval-shaped mesa around the Tower suggests the old volcano's shape. The red rock is the Permian-Triassic Spearfish Formation, and above that is the younger, white Gypsum Springs Formation. Aerial photo by Doc Searls, 2010.
Red sandstone and siltstone cliffs above the Belle Fourche River
Map of Wyoming National Parks and landmarks, showing Devils Tower (upper right) far east of Yellowstone (upper left), north across the state from Cheyenne.

The landscape surrounding Devils Tower is composed mostly of sedimentary rocks. The oldest rocks visible in Devils Tower National Monument were laid down in a shallow sea during the Triassic period, 225 to 195 million years ago. This dark red sandstone and maroon siltstone, interbedded with shale, can be seen along the Belle Fourche RiverOxidation of iron minerals causes the redness of the rocks. This rock layer is known as the Spearfish Formation.

Above the Spearfish formation is a thin band of white gypsum, called the Gypsum Springs Formation. This layer of gypsum was deposited during the Jurassic period, 195 to 136 million years ago.

Created as sea levels and climates repeatedly changed, gray-green shales (deposited in low-oxygen environments such as marshes) were interbedded with fine-grained sandstones, limestones, and sometimes thin beds of red mudstone. This composition, called the Stockade Beaver member, is part of the Sundance Formation. The Hulett Sandstone member, also part of the Sundance formation, is composed of yellow fine-grained sandstone. Resistant to weathering, it forms the nearly vertical cliffs which encircle the Tower itself.

About 65 million years ago, during the Tertiary period, the Rocky Mountains and the Black Hills were uplifted.Magma rose through the crust, intruding into the existing sedimentary rock layers.


Theories of formation                                                                            G

eologists agree that Devils Tower was formed by the intrusion of igneous material. What they cannot agree upon is how, exactly, that process took place. Geologists Carpenter and Russell studied Devils Tower in the late 19th century and came to the conclusion that the Tower was indeed formed by an igneous intrusion. Later geologists searched for further explanations. Several geologists believe the molten rock comprising the Tower might not have surfaced; other researchers are convinced the tower is all that remains of what once was a large explosive volcano.

In 1907, scientists Darton and O'Hara decided that Devils Tower must be an eroded remnant of a laccolith. A laccolith is a large mass of igneous rock which is intruded through sedimentary rock beds but does not actually reach the surface, producing a rounded bulge in the sedimentary layers above. This theory was quite popular in the early 20th century since numerous studies had earlier been done on a number of laccoliths in the Southwest.

Other theories have suggested that Devils Tower is a volcanic plug or that it is the neck of an extinct volcano. Presumably, if Devils Tower was a volcanic plug, any volcanics created by it — volcanic ash, lava flows, volcanic debris — would have been eroded away long ago. Some pyroclastic material of the same age as Devils Tower has been identified elsewhere in Wyoming.

Geologists classify the igneous material as phonolite porphyry, a light to dark-gray or greenish-gray igneous rock with conspicuous crystals of white feldspar.[5] As the lava cooled, hexagonal (and sometimes 4-, 5-, and 7-sided) columns formed. As the rock continued to cool, the vertical columns shrank horizontally in volume and cracks began to occur at 120 degree angles, generally forming compact 6-sided columns. Superficially similar, but with typically 2 feet (0.61 m) diameter columns, Devils Postpile National Monument and Giant's Causeway arecolumnar basalt.

Devils Tower did not visibly protrude out of the landscape until the overlying sedimentary rocks eroded away. As the elements wore down the softer sandstones and shales, the more resistant igneous rock making up the tower survived the erosional forces. As a result, the gray columns of Devils Tower began to appear as an isolated mass above the landscape.

As rain and snow continue to erode the sedimentary rocks surrounding the Tower's base, more of Devils Tower will be exposed. Nonetheless, the exposed portions of the Tower still experience certain amounts of erosion. Cracks along the columns are subject to water and ice erosion. Erosion due to the expansion of ice along cracks and fractures within rock formations is common in colder climates — a prime example being the featured formations at Bryce Canyon National Park. Portions, or even entire columns, of rock at Devils Tower are continually breaking off and falling. Piles of broken columns, boulders, small rocks, and stones — or scree — lie at the base of the tower, indicating that it was once wider than it is today.

AYERS ROCK



Uluru , also known as Ayers Rock, is a large sandstone rock formation in the southern part of the Northern Territorycentral Australia. It lies 335 km (208 mi) south west of the nearest large town, Alice Springs; 450 km (280 mi) by road. Kata Tjuta and Uluru are the two major features of the Uluṟu-Kata Tjuṯa National Park. Uluru is sacred to the Pitjantjatjara and Yankunytjatjara, the Aboriginal people of the area. It has many springs, waterholes, rock caves and ancient paintings. Uluru is listed as a World Heritage Site.

Geology

Uluru rock formations

Uluru is an inselberg, literally "island mountain", an isolated remnant left after the slow erosion of an original mountain range. Uluru is also often referred to as a monolith, although this is a somewhat ambiguous term that is generally avoided by geologists. The remarkable feature of Uluru is its homogeneity and lack of jointing and parting at bedding surfaces, leading to the lack of development of scree slopes and soil. These characteristics led to its survival, while the surrounding rocks were eroded. For the purpose of mapping and describing the geological history of the area, geologists refer to the rock strata making up Uluru as the Mutitjulu Arkose, and it is one of many sedimentary formationsfilling the Amadeus Basin.

Composition

Uluru is dominantly composed of coarse-grained arkose, a type of sandstone characterized by an abundance of feldspar, and some conglomerate.Average composition is 50% feldspar, 25–35% quartz and up to 25% rock fragments; most feldspar is K-feldspar with only minor plagioclase as subrounded grains and highly altered inclusions within K-feldspar.The grains are typically 2–4 millimetres (0.079–0.16 in) in diameter, and are angular to subangular; the finer sandstone is well sorted, with sorting decreasing with increasing grain size. The rock fragments include subrounded basalt, invariably replaced to various degrees by chlorite and epidote. The minerals present suggest derivation from a predominantly granite source, similar to the Musgrave Block exposed to the south. When relatively fresh, the rock has a grey colour, but weathering of iron-bearing minerals by the process of oxidation gives the outer surface layer of rock a red-brown rusty colour. Features related to deposition of the sediment include cross-bedding and ripples, analysis of which indicated deposition from broad shallow high energy fluvial channels and sheet flooding, typical of alluvial fans.

Rain water flows off Uluru along channels marked by dark algae, forming small ponds at the base

Age and origin

The Mutitjulu Arkose is believed to be of about the same age as the conglomerate at Kata Tjuta, and to have a similar origin despite the rock type being different, but it is younger than the rocks exposed to the east at Mount Conner, and unrelated to them. The strata at Uluru are nearly vertical, dipping to the south west at 85°, and have an exposed thickness of at least 2,400 m (7,900 ft). The strata dip below the surrounding plain and no doubt extend well beyond Uluru in the subsurface, but the extent is not known. The rock was originally sand, deposited as part of an extensive alluvial fan that extended out from the ancestors of the Musgrave, Mann and Petermann Ranges to the south and west, but separate from a nearby fan that deposited the sand, pebbles and cobbles that now make up Kata Tjuta. The similar mineral composition of the Mutitjulu Arkose and the granite ranges to the south is now explained. The ancestors of the ranges to the south were once much larger than the eroded remnants we see today. They were thrust up during a mountain building episode referred to as the Petermann Orogeny that took place in late Neoproterozoic to early Cambrian times (550-530 Ma), and thus the Mutitjulu Arkose is believed to have been deposited at about the same time. The arkose sandstone which makes up the formation is composed of grains that show little sorting based on grain size, exhibit very little rounding and the feldspars in the rock are relatively fresh in appearance. This lack of sorting and grain rounding is typical of arkosic sandstones and is indicative of relatively rapid erosion from the granites of the growing mountains to the south. The layers of sand were nearly horizontal when deposited, but were tilted to their near vertical position during a later episode of mountain building, possibly the Alice Springs Orogeny of Palaeozoic age (400-300 Ma).


ARCHES NATIONAL PARK

delicate-arch-arches-national-park-utah

Arches National Park is a U.S. National Park in eastern Utah. It is known for preserving over 2000 natural sandstone arches, including the world-famous Delicate Arch, in addition to a variety of unique geological resources and formations.

The park is located just outside of Moab, Utah, and is 119 square miles (310 km2) in size. Its highest elevation is 5,653 feet (1,723 m) at Elephant Butte, and its lowest elevation is 4,085 feet (1,245 m) at the visitor center. Forty-three arches have collapsed due to erosion since 1970. The park receives 10 inches (250 mm) of rain a year on average.

Administered by the National Park Service, the area was originally designated as a National Monument on April 12, 1929. It was redesignated as a National Park on November 12, 1971



Geology
Map of Arches National Park.
The Organ is an impressive "sandstone fin."
Delicate Arch

The national park lies atop an underground evaporite layer or salt bed, which is the main cause of the formation of the arches, spires, balanced rocks, sandstone fins, and eroded monoliths in the area. This salt bed is thousands of feet thick in places, and was deposited in the Paradox Basin of the Colorado Plateau some 300 million years ago when a sea flowed into the region and eventually evaporated. Over millions of years, the salt bed was covered with debris eroded from theUncompahgre Uplift to the northeast. During the Early Jurassic (about 210 Ma) desert conditions prevailed in the region and the vast Navajo Sandstone was deposited. An additional sequence of stream laid and windblown sediments, the Entrada Sandstone (about 140 Ma), was deposited on top of the Navajo. Over 5000 feet (1500 m) of younger sediments were deposited and have been mostly eroded away. Remnants of the cover exist in the area including exposures of the CretaceousMancos Shale. The arches of the area are developed mostly within the Entrada formation.

The weight of this cover caused the salt bed below it to liquefy and thrust up layers of rock into salt domes. The evaporites of the area formed more unusual salt anticlines or linear regions of uplift.Faulting occurred and whole sections of rock subsided into the areas between the domes. In some places, they turned almost on edge. The result of one such 2,500-foot (760 m) displacement, theMoab Fault, is seen from the visitor center.

As this subsurface movement of salt shaped the landscape, erosion removed the younger rock layers from the surface. Except for isolated remnants, the major formations visible in the park today are the salmon-colored Entrada Sandstone, in which most of the arches form, and the buff-coloredNavajo Sandstone. These are visible in layer cake fashion throughout most of the park. Over time, water seeped into the surface cracks, joints, and folds of these layers. Ice formed in the fissures, expanding and putting pressure on surrounding rock, breaking off bits and pieces. Winds later cleaned out the loose particles. A series of free-standing fins remained. Wind and water attacked these fins until, in some, the cementing material gave way and chunks of rock tumbled out. Many damaged fins collapsed. Others, with the right degree of hardness and balance, survived despite their missing sections. These became the famous arches.


Death Valley

Death Valley

Satellite photo of Death Valley
Death Valley is located in California
Death Valley
Floor elevation−282 ft (−86 m)



Death Valley is a desert valley located in Eastern California. Situated within the Mojave Desert, it features the lowest, driest, and hottest locations in North AmericaBadwater, a basin located in Death Valley, is the specific location (36° 15' N 116° 49.5' W) of the lowestelevation in North America at 282 feet (86.0 m) below sea level. This point is only 84.6 miles (136.2 km) ESE of Mount Whitney, the highest point in the contiguous United States with an elevation of 14,505 feet (4,421 m). Death Valley holds the record for the highest reliably reported temperature in the Western hemisphere, 134 °F (56.7 °C) at Furnace Creek on July 10, 1913—just short of the world record, 136 °F (57.8 °C) in Al 'AziziyahLibya, on September 13, 1922.

Located near the border of California and Nevada, in the Great Basin, east of the Sierra Nevada mountains, Death Valley constitutes much of Death Valley National Park and is the principal feature of the Mojave and Colorado Deserts Biosphere Reserve. It is located mostly in Inyo County, California. It runs from north to south between the Amargosa Range on the east and the Panamint Range on the west; the Sylvania Mountains and the Owlshead Mountains form its northern and southern boundaries, respectively. It has an area of about 3,000 sq mi (7,800 km2). Death Valley shares many characteristics with other places below sea level.


[edit]Geology

Death Valley is one of the best geological examples of a basin and range configuration. It lies at the southern end of a geological troughknown as Walker Lane, which runs north into Oregon. The valley is bisected by a right lateral strike slip fault system, represented by theDeath Valley Fault and the Furnace Creek Fault. The eastern end of the left lateral Garlock Fault intersects the Death Valley Fault. Furnace Creek and the Amargosa River flow through the valley but eventually disappear into the sands of the valley floor.

Death Valley also contains salt pans. According to current geological consensus, during the middle of the Pleistocene era there was a succession of inland seas (collectively referred to as Lake Manly) located where Death Valley is today. As the area turned to desert the water evaporated, leaving behind the abundance of evaporitic salts such as common sodium salts and borax, which were subsequently exploited during the modern history of the region, primarily 1883 to 1907.

Dunes at Death Valley, looking east towards Nevada.

As a general rule, lower altitudes tend to have higher temperatures where the sun heats the ground and that heat is then radiated upward, but as the air begins to rise it is trapped by (1) the surrounding elevation and (2) the weight of the air (essentially the atmospheric pressure) above it. The atmospheric pressure is higher at very low altitudes than it is under the same conditions at sea level because there is more air (more distance) between the ground and the top of the atmosphere. This pressure traps the heat near the ground, and also creates wind currents that circulate very hot air, thereby distributing the heat to all areas, regardless of shade and other factors.[7]

This process is especially important in Death Valley as it provides its specific climate and geography. The valley is surrounded by mountains, while its surface is mostly flat and devoid of plants, and of which a high percentage of the sun's heat is able to reach the ground, absorbed by soil and rock. When air at ground level is heated, it begins to rise, moving up past steep high mountain ranges, which then cools slightly, sinking back down towards the valley more compressed. This air is then reheated by the sun to a higher temperature, moving up the mountain again, whereby the air moves up and down in a circular motion in cycles, similar to how a convection oven works, albeit a natural one. This superheated air increases ground temperature markedly, forming the hot wind currents that are trapped by atmospheric pressure and mountains, thus stays mostly within the valley. Such hot wind currents contribute to perpetual drought-like conditions in Death Valley and prevent much cloud formation to pass through the confines of the valley, where precipitation is often in the form of a virga.[8] Death Valley holds temperature records because it has an unusually high number of factors that lead to high atmospheric temperatures.





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