|
Tanner Graben
Located directly downstream of the Little Colorado River confluence with the Colorado River, the Tanner Graben, in the Grand Canyon, Arizona, US is a prominence and cliffside rock formation below the East Rim. Tanner Graben is located riverside, on the Colorado River, on a north-northwest bank at Mile 68.5, and lies opposite Tanner Canyon. The Tanner Rapid, created by Tanner Creek lies at the riverside foot of the graben. The graben is a pronounced feature because of the black Cardenas Basalt that forms the middle section of the graben, presumably free of debris accumulation by its cliff face steepness, and winds, and airflow drainage that course through the Colorado River's canyons; unprotected side canyons of Cardenas Basalt show accumulations as a slope-forming geologic unit, with little showing of black basalt. The Tanner Graben sits on the Butte Fault which trends north-south up the Colorado River, and the west side of Temple Butte; it forms the east flank of Tanner Grabe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aubrey Peak Wilderness
The Aubrey Peak Wilderness is a wilderness administered by the Bureau of Land Management (BLM). The wilderness is located in northwest Arizona in the southwest of Mohave County, a region of the southeastern Mojave Desert's extension into northwest Arizona. The wilderness is one of two in the Rawhide Mountains, which border the north bank of the west-flowing Bill Williams River. The other wilderness is on both sides of the river, the Rawhide Mountains Wilderness; the section south of the river is in the northeast of the Buckskin Mountains, and the southeast of the Rawhides. The Buckskin Wilderness is on the western border of Alamo Lake, of Alamo Lake State Park. The Aubrey Peak Wilderness is about northeast of Parker Dam, California on the Colorado River, near its confluence with the Bill Williams. The confluence has the following sites: :# Bill Williams National Wildlife Preserve :# Buckskin Mountain State Park :# Cattail Cove State Park :#Parker Dam Peaks of the wildern ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Butte Fault
__NOTOC__ In geomorphology, a butte () is an isolated hill with steep, often vertical sides and a small, relatively flat top; buttes are smaller landforms than mesas, plateaus, and table (landform), tablelands. The word ''butte'' comes from a French language, French word meaning Hillock, knoll (but of any size); its use is prevalent in the Western United States, including the Southwestern United States, southwest where ''mesa'' (Spanish language, Spanish for "table") is used for the larger landform. Due to their distinctive shapes, buttes are frequently landmarks in plains and mountainous areas. To differentiate the two landforms, geographers use the rule of thumb that a mesa has a top that is wider than its height, while a butte has a top that is narrower than its height. Formation Buttes form by weathering and erosion when hard caprock overlies a layer of less resistant rock (geology), rock that is eventually worn away. The harder rock on top of the butte resists erosion. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sixtymile Formation
The Sixtymile Formation is a very thin accumulation of sandstone, siltstone, and breccia underlying the Tapeats Sandstone that is exposed in only four places in the Chuar Valley. These exposures occur atop Nankoweap Butte and within Awatubi and Sixtymile Canyons in the eastern Grand Canyon, Arizona. The maximum preserved thickness of the Sixtymile Formation is about . The actual depositional thickness of the Sixtymile Formation is unknown owing to erosion prior to deposition of the Tapeats Sandstone.Dehler, CM, SM Porter, and JM Timmons (2012) ''The Neoproterozoic Earth system revealed from the Chuar Group of Grand Canyon.'', in JM Timmons and KE Karlstrom, eds., pp. 49–72, ''Grand Canyon Geology: Two Billion Years of Earth's History.'' Special Paper no. 489. Geological Society of America, Boulder, Colorado. Sixtymile Formation and the underlying Chuar Group are preserved only in a broad asymmetric fold comprising both units, called the Chuar syncline. The ''Chuar Syncline'' is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stratigraphy Of The Grand Canyon
Stratigraphy is a branch of geology concerned with the study of rock layers (strata) and layering (stratification). It is primarily used in the study of sedimentary and layered volcanic rocks. Stratigraphy has three related subfields: lithostratigraphy (lithologic stratigraphy), biostratigraphy (biologic stratigraphy), and chronostratigraphy (stratigraphy by age). Historical development Catholic priest Nicholas Steno established the theoretical basis for stratigraphy when he introduced the law of superposition, the principle of original horizontality and the principle of lateral continuity in a 1669 work on the fossilization of organic remains in layers of sediment. The first practical large-scale application of stratigraphy was by William Smith in the 1790s and early 19th century. Known as the "Father of English geology", Smith recognized the significance of strata or rock layering and the importance of fossil markers for correlating strata; he created the first geologic map o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Comanche Point (Grand Canyon)
Comanche Point is a summit located in the Grand Canyon, in Coconino County of northern Arizona, US. Part of the ''Palisades of the Desert'', Comanche Point is the high point on the canyon's less-visited East Rim, and is four miles north-northeast of Desert View Point, its nearest higher neighbor. Topographic relief is significant as it towers above the Colorado River in 1.5 mile. Comanche Point was named in 1900 by George Wharton James for the Comanche, a Native-American nation from the Great Plains, in keeping with a practice of naming the points on the canyon's South Rim for Native American nations. This geographical feature's name was officially adopted in 1906 by the U.S. Board on Geographic Names. According to the Köppen climate classification system, Comanche Point is located in a Cold semi-arid climate zone. On September 27, 1994, the tabloid Weekly World News ran an outlandish cover story that wreckage of a 4000-year-old UFO had been found in limestone rubble ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Desert View Watchtower
Desert View Watchtower, also known as the Indian Watchtower at Desert View, is a -high stone building located on the South Rim of the Grand Canyon within Grand Canyon National Park in Arizona, United States. The tower is located at Desert View, more than to the east of the main developed area at Grand Canyon Village, toward the east entrance to the park. The four-story structure, completed in 1932, was designed by American architect Mary Colter, an employee of the Fred Harvey Company who also created and designed many other buildings in the Grand Canyon vicinity including Hermit's Rest and the Lookout Studio. The interior contains murals by Fred Kabotie. Description The watchtower was the last of the series of Mary Colter-designed visitor concession structures at the Grand Canyon until her renovation of the Bright Angel Lodge in 1935. The tower was designed to resemble an Ancestral Puebloan watchtower, but its size dwarfs any known Pueblan-built tower. The closest prototype ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tanner Trail
The Tanner Trail is a hiking trail located on the South Rim of the Grand Canyon National Park, located in the U.S. state of Arizona. The trailhead is located at Lipan Point, a prominent lookout located to the east of the Grand Canyon Village, and the trail ends at the Colorado River at Tanner Rapids. History The Tanner Trail started out as an ancient Anasazi and Hopi route to the Colorado River. Most believe today that Tanner Canyon is where García López de Cárdenas became the first European to encounter the Grand Canyon. The trail is named after Seth Tanner, a 19th-century prospector who improved the trail so he would have better access to his copper mine. It is also believed that Tanner Canyon was once used as an old horse thief trail where buried gold known as Long Tom's treasure is located. The horse thieves would use the canyon to bring the horses from Arizona into Utah. While in the canyon, the horse thieves would change the brands of the horses, then they w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caprock
Caprock or cap rock is a more resistant rock type overlying a less resistant rock type,Kearey, Philip (2001). ''Dictionary of Geology'', 2nd ed., Penguin Reference, London, New York, etc., p. 41.. . analogous to an upper crust on a cake that is harder than the underlying layer. Description The Niagara Escarpment, over which Niagara Falls flows, is an example of a scarp or escarpment. At Niagara Falls, the caprock is the riverbed above the falls, and is what prevents the river from eroding the face of the falls very quickly. In the photo, the dark thin layer in the foreground where water is not yet running, is the caprock. The Niagara caprock is made of dolomitic limestone. Other common types of caprock are sandstone and mafic rock. In processes such as scarp retreat, the caprock controls the rate of erosion of the scarp. As the softer rock is cut away, periodically the caprock shears off. Caprock is also found in salt domes and on the top of mesa formations. Petroleum In the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fault (geology)
In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tectonic forces, with the largest forming the boundaries between the plates, such as the megathrust faults of subduction zones or transform faults. Energy release associated with rapid movement on active faults is the cause of most earthquakes. Faults may also displace slowly, by aseismic creep. A ''fault plane'' is the plane that represents the fracture surface of a fault. A ''fault trace'' or ''fault line'' is a place where the fault can be seen or mapped on the surface. A fault trace is also the line commonly plotted on geologic maps to represent a fault. A ''fault zone'' is a cluster of parallel faults. However, the term is also used for the zone of crushed rock along a single fault. Prolonged motion along closely spaced faults can blur the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unkar Group
The Unkar Group is a sequence of strata of Proterozoic age that are subdivided into five geologic formations and exposed within the Grand Canyon, Arizona, Southwestern United States. The 5-unit Unkar Group is the basal member of the 8-member Grand Canyon Supergroup. The Unkar is about thick and composed, in ascending order, of the Bass Formation, Hakatai Shale, Shinumo Quartzite, Dox Formation, and Cardenas Basalt. Units 4 & 5 are found mostly in the eastern region of Grand Canyon. Units 1 through 3 are found in central Grand Canyon. The Unkar Group accumulated approximately between 1250 and 1104 Ma (1,104 million years ago, 1.1 billion). In ascending order, the Unkar Group is overlain by the Nankoweap Formation, about thick; the Chuar Group, about thick; and the Sixtymile Formation, about thick. These are all of the units of the Grand Canyon Supergroup.Hendricks, JD, and GM Stevenson (2003) ''Grand Canyon Supergroup: Unkar Group.'' In SS Beus and M Morales, eds., ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grand Canyon Supergroup
The Grand Canyon Supergroup is a Mesoproterozoic to a Neoproterozoic sequence of sedimentary strata, partially exposed in the eastern Grand Canyon of Arizona. This group comprises the Unkar Group, Nankoweap Formation, Chuar Group and the Sixtymile Formation, which overlie Vishnu Basement Rocks. Several notable landmarks of the Grand Canyon, such as the Isis Temple and Cheops Pyramid, and the Apollo Temple, are surface manifestations of the Grand Canyon Supergroup. Geology The Grand Canyon Supergroup overlies the Vishnu Basement Rocks but was never subjected to metamorphism. The units of the Supergroup were faulted and then tilted from 10 to 15 degrees.Timmons, M, KE Karlstrom, and C Dehler (1998''Grand Canyon Supergroup Six Unconformities Make One Great Unconformity A Record of Supercontinent Assembly and Disassembly''Boatman's Quarterly Review. vol. 12, no. 1, pp. 29–32. online: accessed April 2014 A section of the Unkar Group members is visible north of Grand Canyon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Precambrian
The Precambrian (or Pre-Cambrian, sometimes abbreviated pꞒ, or Cryptozoic) is the earliest part of Earth's history, set before the current Phanerozoic Eon. The Precambrian is so named because it preceded the Cambrian, the first period of the Phanerozoic Eon, which is named after Cambria, the Latinised name for Wales, where rocks from this age were first studied. The Precambrian accounts for 88% of the Earth's geologic time. The Precambrian is an informal unit of geologic time, subdivided into three eons ( Hadean, Archean, Proterozoic) of the geologic time scale. It spans from the formation of Earth about 4.6 billion years ago ( Ga) to the beginning of the Cambrian Period, about million years ago ( Ma), when hard-shelled creatures first appeared in abundance. Overview Relatively little is known about the Precambrian, despite it making up roughly seven-eighths of the Earth's history, and what is known has largely been discovered from the 1960s onwards. The Precambrian fossil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
