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Tower Of Ra
Tower of Ra is a pillar located in the Grand Canyon, in Coconino County of Arizona, US. Its summit is situated five miles north of Pima Point overlook on the canyon's South Rim, three miles southeast of Confucius Temple, and two miles northwest of Tower of Set, where it towers over above the Colorado River. Tower of Ra was named in 1879 by Thomas Moran, for Ra, the Egyptian deity of the sun. This followed the naming convention of Clarence Dutton who began the tradition of naming geographical features in the Grand Canyon after mythological deities. This mountain's name was officially adopted in 1906 by the U.S. Board on Geographic Names. The first ascent was made in 1977 by Jim Haggart, Art Christiansen, and Barbara Zinn. According to the Köppen climate classification system, Tower of Ra is located in a cold semi-arid climate zone. Geology The top of Tower of Ra is composed of the reddish Pennsylvanian-Permian Supai Group.N.H. Darton, ''Story of the Grand Canyon of Arizona' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Osiris Temple
Osiris Temple is a 6,613 ft elevation summit located in the Grand Canyon, in Coconino County of Arizona, US. This butte is situated approximately (2.27 mi) southwest of Shiva Temple, in the Upper Trinity Creek watershed, a north watershed into the Colorado River at Granite Gorge.Osiris Temple is the highest prominence in a series of three connected landforms extending south to Granite Gorge, namely Osiris Temple, Horus Temple, and Tower of Set. The western flanks of the landforms drain into regions of Lower Ninetyfour Mile Creek & Canyon; the eastern flanks drainage is into Trinity Canyon. The headwaters of Trinity Canyon is the southern flank of Shiva Temple, the parent landform of Osiris Temple. The Shiva Temple is a heavily forested tableland-butte, one of two such remnants of the North Rim ( Kaibab Plateau). The other tableland is Wotans Throne, adjacent Cape Royal Cape Royal is a 7,880+-cliff-elevation summit located in the eastern Grand Canyon, Coconino Cou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Naming Convention
A naming convention is a convention (generally agreed scheme) for naming things. Conventions differ in their intents, which may include to: * Allow useful information to be deduced from the names based on regularities. For instance, in Manhattan, streets are consecutively numbered; with east–west streets called "Streets" and north–south streets called "Avenues". * Show relationships, and in most personal naming conventions * Ensure that each name is unique for same scope Use cases Well-chosen naming conventions aid the casual user in navigating and searching larger structures. Several areas where naming conventions are commonly used include: * In astronomy, planetary nomenclature * In classics, Roman naming conventions * In computer programming, identifier naming conventions * In computer networking, naming scheme * In humans, naming offspring * In industry, product naming conventions * In the sciences, systematic names for a variety of things Examples Examples of naming c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vishnu Basement Rocks
The Vishnu Basement Rocks is the name recommended for all Early Proterozoic crystalline rocks (metamorphic and igneous) exposed in the Grand Canyon region. They form the crystalline basement rocks that underlie the Bass Limestone of the Unkar Group of the Grand Canyon Supergroup and the Tapeats Sandstone of the Tonto Group. These basement rocks have also been called either the Vishnu Complex or Vishnu Metamorphic Complex. These Early Proterozoic crystalline rocks consist of metamorphic rocks that are collectively known as the ''Granite Gorge Metamorphic Suite''; sections of the Vishnu Basement Rocks contain Early Paleoproterozoic granite, granitic pegmatite, aplite, and granodiorite that have intruded these metamorphic rocks, and also, intrusive Early Paleoproterozoic ultramafic rocks.Anonymous (nd''Vishnu Basement Rocks.''U. S. Geological Survey, Reston, Virginia.Karlstrom, KE, BR Ilg, Bradley, D Hawkins, ML Williams, G Dumond, KK. Mahan, and SA Bowring, Samuel (2012) ''Vishnu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paleoproterozoic
The Paleoproterozoic Era (;, also spelled Palaeoproterozoic), spanning the time period from (2.5–1.6 Ga), is the first of the three sub-divisions (eras) of the Proterozoic Eon. The Paleoproterozoic is also the longest era of the Earth's geological history. It was during this era that the continents first stabilized. Paleontological evidence suggests that the Earth's rotational rate ~1.8 billion years ago equated to 20-hour days, implying a total of ~450 days per year. Atmosphere Before the enormous increase in atmospheric oxygen, almost all existing lifeforms were anaerobic organisms whose metabolism was based on a form of cellular respiration that did not require oxygen. Free oxygen in large amounts is toxic to most anaerobic organisms. Consequently, most died when the atmospheric free oxygen levels soared in an extinction event called the Great Oxidation Event, which brought atmospheric oxygen levels to up to 10% of their current level. The only creatures that survi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tonto Group
The Tonto Group is a name for an assemblage of related sedimentary strata, collectively known by geologists as a ''Group'', that comprises the basal sequence Paleozoic strata exposed in the sides of the Grand Canyon. As currently defined, the Tonto groups consists of the Sixtymile Formation, Tapeats Sandstone, Bright Angel Shale (or Formation), Muav Limestone (or Formation), and Frenchman Mountain Dolostone. Historically, it included only the Tapeats Sandstone, Bright Angel Shale, and Muav Limestone.Karlstrom, K.E., Mohr, M.T., Schmitz, M.D., Sundberg, F.A., Rowland, S.M., Blakey, R., Foster, J.R., Crossey, L.J., Dehler, C.M. and Hagadorn, J.W., 2020. ''Redefining the Tonto Group of Grand Canyon and recalibrating the Cambrian time scale''. ''Geology'', 48(5), pp. 425–430.Connors, T.B., Tweet, J.S., and Santucci, V.L., 2020. ''Stratigraphy of Grand Canyon National Park''. In: Santucci, V.L., Tweet, J.S., ed., pp. 54–74, ''Grand Canyon National Park: Centennial Paleontologica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cambrian
The Cambrian Period ( ; sometimes symbolized C with bar, Ꞓ) was the first geological period of the Paleozoic Era, and of the Phanerozoic Eon. The Cambrian lasted 53.4 million years from the end of the preceding Ediacaran Period 538.8 million years ago (mya) to the beginning of the Ordovician Period mya. Its subdivisions, and its base, are somewhat in flux. The period was established as "Cambrian series" by Adam Sedgwick, who named it after Cambria, the Latin name for 'Cymru' (Wales), where Britain's Cambrian rocks are best exposed. Sedgwick identified the layer as part of his task, along with Roderick Murchison, to subdivide the large "Transition Series", although the two geologists disagreed for a while on the appropriate categorization. The Cambrian is unique in its unusually high proportion of sedimentary deposits, sites of exceptional preservation where "soft" parts of organisms are preserved as well as their more resistant shells. As a result, our understanding of the Ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Redwall Limestone
The Redwall Limestone is a resistant cliff-forming unit of Mississippian age that forms prominent, red-stained cliffs in the Grand Canyon, ranging in height from to . Lithology Redwall Limestone consists predominantly of light-olive-gray to light-gray, fine- to coarse-grained, thin- to thick-bedded, often cherty, limestone. Its lower part consists of brownish-gray, interbedded finely crystalline dolomite and fine- to coarse-grained limestone with layers of white chert lenses and yellowish-gray and brownish-gray, cliff-forming, thick-bedded, fine-grained dolomite. It is divided into Horseshoe Mesa Member, Mooney Falls Member, Thunder Springs Member, and Whitmore Wash Member.Chronic, H (1983) ''Roadside Geology of Arizona.'' The Mountaineers Books, Seattle, Washington. (softcover, ) Its origins date to the Mississippian age. Contacts The upper and lower contacts of the Redwall Limestone are both unconformities. Locally, the Redwall Limestone directly overlies the unconformity ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mississippian (geology)
The Mississippian ( , also known as Lower Carboniferous or Early Carboniferous) is a subperiod in the geologic timescale or a subsystem of the geologic record. It is the earlier of two subperiods of the Carboniferous period lasting from roughly 358.9 to 323.2 million years ago. As with most other geochronologic units, the rock beds that define the Mississippian are well identified, but the exact start and end dates are uncertain by a few million years. The Mississippian is so named because rocks with this age are exposed in the Mississippi Valley. The Mississippian was a period of marine transgression in the Northern Hemisphere: the sea level was so high that only the Fennoscandian Shield and the Laurentian Shield were dry land. The cratons were surrounded by extensive delta systems and lagoons, and carbonate sedimentation on the surrounding continental platforms, covered by shallow seas. In North America, where the interval consists primarily of marine limestones, it is treate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Supai Group
The Supai Group is a slope-forming section of red bed deposits found in the Colorado Plateau. The group was laid down during the Pennsylvanian to Lower Permian. Cliff-forming interbeds of sandstone are noticeable throughout the group. The Supai Group is especially exposed throughout the Grand Canyon in northwest Arizona, as well as local regions of southwest Utah, such as the Virgin River valley region. It occurs in Arizona at Chino Point, Sycamore Canyon, and famously at Sedona as parts of Oak Creek Canyon. In the Sedona region, it is overlain by the Hermit Formation, and the colorful Schnebly Hill Formation. The Supai Group is coeval with the Hermosa Group of east and south Utah; the Hermosa Group extended southeastwards from Utah to Durango, extreme southwest Colorado, and adjacent to the Hermosa type section. The Supai Group was originally designated as the Supai Formation by N.H. Darton in 1910 for exposures at Supai, Arizona. It was first raised to group stratigrap ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Permian
The Permian ( ) is a geologic period and stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last period of the Paleozoic Era; the following Triassic Period belongs to the Mesozoic Era. The concept of the Permian was introduced in 1841 by geologist Sir Roderick Murchison, who named it after the region of Perm in Russia. The Permian witnessed the diversification of the two groups of amniotes, the synapsids and the sauropsids ( reptiles). The world at the time was dominated by the supercontinent Pangaea, which had formed due to the collision of Euramerica and Gondwana during the Carboniferous. Pangaea was surrounded by the superocean Panthalassa. The Carboniferous rainforest collapse left behind vast regions of desert within the continental interior. Amniotes, which could better cope with these drier conditions, rose to dominance in place of their am ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pennsylvanian (geology)
The Pennsylvanian ( , also known as Upper Carboniferous or Late Carboniferous) is, in the International Commission on Stratigraphy, ICS geologic timescale, the younger of two period (geology), subperiods (or upper of two system (stratigraphy), subsystems) of the Carboniferous Period. It lasted from roughly . As with most other geochronology, geochronologic units, the stratum, rock beds that define the Pennsylvanian are well identified, but the exact date of the start and end are uncertain by a few hundred thousand years. The Pennsylvanian is named after the U.S. state of Pennsylvania, where the coal-productive beds of this age are widespread. The division between Pennsylvanian and Mississippian (geology), Mississippian comes from North American stratigraphy. In North America, where the early Carboniferous beds are primarily marine limestones, the Pennsylvanian was in the past treated as a full-fledged geologic period between the Mississippian and the Permian. In parts of Europe, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cold Semi-arid Climate
A semi-arid climate, semi-desert climate, or steppe climate is a dry climate sub-type. It is located on regions that receive precipitation below potential evapotranspiration, but not as low as a desert climate. There are different kinds of semi-arid climates, depending on variables such as temperature, and they give rise to different biomes. Defining attributes of semi-arid climates A more precise definition is given by the Köppen climate classification, which treats steppe climates (''BSk'' and ''BSh'') as intermediates between desert climates (BW) and humid climates (A, C, D) in ecological characteristics and agricultural potential. Semi-arid climates tend to support short, thorny or scrubby vegetation and are usually dominated by either grasses or shrubs as it usually can't support forests. To determine if a location has a semi-arid climate, the precipitation threshold must first be determined. The method used to find the precipitation threshold (in millimeters): *multiply ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
