|
Mount Huethawali
Mount Huethawali is a summit located in the Grand Canyon, in Coconino County of northern Arizona, US. It is situated 3.5 miles due east of Explorers Monument, 1.5 mile west of Grand Scenic Divide, and immediately southwest of Huxley Terrace. Surrounded by Garnet, Evolution, and Bass Canyons, Huethawali rises over above Darwin Plateau, and over 4,000 feet higher than the nearby Colorado River. The summit dome is composed of cream-colored Permian Coconino Sandstone. This sandstone, which is the third-youngest stratum in the Grand Canyon, was deposited 265 million years ago as sand dunes. Below the Coconino Sandstone is reddish, slope-forming, Permian Hermit Formation, which in turn overlays the Pennsylvanian-Permian Supai Group. Further down are strata of the cliff-forming Mississippian Redwall Limestone, Cambrian Tonto Group, and finally Proterozoic Unkar Group at river level. According to the Köppen climate classification system, Mount Huethawali is located in a cold ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fossil Mountain (Grand Canyon)
Fossil Mountain is a 6,729-foot-elevation summit located in the Western Grand Canyon, in Coconino County of northern Arizona, Southwestern United States. It is situated ~1.5 miles due east of Mount Huethawali, about 1.0 miles southeast of the Grand Scenic Divide, and 1.0 mi west of Havasupai Point. The Fossil Mountain prominence is a massif-remainder cliff of Kaibab Limestone, and stands above a tableland of the South Rim, a forested plateau of Kaibab Limestone. Geology Photos of the Fossil Mountain prominence, a large cliff of Kaibab Limestone, can be seen at Summitpost. (2 photos, Summitpost/ref> The southwest slope of Fossil Mountain is a highly vegetated (trees), and high angle slope to the prominence. Below the ~350 ft cliff of Kaibab Limestone is about ~250 ft of vegetated slope-former, slope-forming Toroweap Formation. The Toroweap sits upon a ~500 cliff-formed, Coconino Sandstone, very vertical, and uneroded, (northeast face of Fossil Mountain, overl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Colorado River
The Colorado River ( es, Río Colorado) is one of the principal rivers (along with the Rio Grande) in the Southwestern United States and northern Mexico. The river drains an expansive, arid drainage basin, watershed that encompasses parts of seven U.S. states and two Mexican states. The name Colorado derives from the Spanish language for "colored reddish" due to its heavy silt load. Starting in the central Rocky Mountains of Colorado, it flows generally southwest across the Colorado Plateau and through the Grand Canyon before reaching Lake Mead on the Arizona–Nevada border, where it turns south toward the Mexico–United States border, international border. After entering Mexico, the Colorado approaches the mostly dry Colorado River Delta at the tip of the Gulf of California between Baja California and Sonora. Known for its dramatic canyons, whitewater rapids, and eleven National parks of the United States, U.S. National Parks, the Colorado River and its tributaries are a v ... [...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] |
Köppen Climate Classification
The Köppen climate classification is one of the most widely used climate classification systems. It was first published by German-Russian climatologist Wladimir Köppen (1846–1940) in 1884, with several later modifications by Köppen, notably in 1918 and 1936. Later, the climatologist Rudolf Geiger (1894–1981) introduced some changes to the classification system, which is thus sometimes called the Köppen–Geiger climate classification system. The Köppen climate classification divides climates into five main climate groups, with each group being divided based on seasonal precipitation and temperature patterns. The five main groups are ''A'' (tropical), ''B'' (arid), ''C'' (temperate), ''D'' (continental), and ''E'' (polar). Each group and subgroup is represented by a letter. All climates are assigned a main group (the first letter). All climates except for those in the ''E'' group are assigned a seasonal precipitation subgroup (the second letter). For example, ''Af'' indi ... [...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] |
Proterozoic
The Proterozoic () is a geological eon spanning the time interval from 2500 to 538.8million years ago. It is the most recent part of the Precambrian "supereon". It is also the longest eon of the Earth's geologic time scale, and it is subdivided into three geologic eras (from oldest to youngest): the Paleoproterozoic, Mesoproterozoic, and Neoproterozoic. The Proterozoic covers the time from the appearance of oxygen in Earth's atmosphere to just before the proliferation of complex life (such as trilobites or corals) on the Earth. The name ''Proterozoic'' combines two forms of ultimately Greek origin: meaning 'former, earlier', and , 'of life'. The well-identified events of this eon were the transition to an oxygenated atmosphere during the Paleoproterozoic; the evolution of eukaryotes; several glaciations, which produced the hypothesized Snowball Earth during the Cryogenian Period in the late Neoproterozoic Era; and the Ediacaran Period (635 to 538.8 Ma) which is characterize ... [...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] |
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] |
