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Uncompahgre Formation
The Uncompahgre Formation is a geologic formation in Colorado. Its radiometric age is between 1707 and 1704 Ma, corresponding to the Statherian period. History The formation was first named by Charles Whitman Cross and Ernest Howe in 1905 for exposures around Uncompahgre Gorge near Ouray, Colorado. They grouped it with the Vallecito Conglomerate into the Needle Mountains Group, but this was abandoned by Tweto in 1977. Karl Karlstrom and coinvestigators informally raised the Uncompahgre Formation to group rank in 2017, assigning the Vallecito Conglomerate as a member. Geology The Uncompahgre Formation is a sequence of quartzite and black phyllite some in thickness. It is exposed in a curving belt from the northwestern to northeastern Needle Mountains with outliers near Ouray and Rico, Colorado. It is interpreted as metamorphosed marine and fluvial sandstone, mudstone, and shale. The formation overlies plutons with an age of 1707 Ma and detrital zircon geochronology ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Formation (stratigraphy)
A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics (lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exposed in a geographical region (the stratigraphic column). It is the fundamental unit of lithostratigraphy, the study of strata or rock layers. A formation must be large enough that it can be mapped at the surface or traced in the subsurface. Formations are otherwise not defined by the thickness (geology), thickness of their rock strata, which can vary widely. They are usually, but not universally, tabular in form. They may consist of a single lithology (rock type), or of alternating beds of two or more lithologies, or even a heterogeneous mixture of lithologies, so long as this distinguishes them from adjacent bodies of rock. The concept of a geologic formation goes back to the beginnings of modern scientific geology. The term was used by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Needle Mountains
The Needle Mountains are a subrange of the San Juan Mountains of the Rocky Mountains located in the southwestern part of the U.S. State of Colorado. Much of the range is protected in the Weminuche Wilderness of the San Juan National Forest. The range is notable for having some of the most rugged mountains in the state, and includes many technical climbs and scrambles. A small but dramatic east–west subrange in the northern section is known as the Grenadier Range. Geology Unlike the rest of the San Juan Mountains, which are volcanic in origin, the Needle Mountains (along with the Grenadier Range) are a mass of uplifted Precambrian rocks. They consist chiefly of quartzite, granite, and amphibolite. The mountains are referred to as the Needle Mountains Uplift. Notable peaks * Mount Eolus, 14,089 ft * Windom Peak, 14,082 ft * Sunlight Peak, 14,059 ft * Pigeon Peak, 13,972 ft * Vestal Peak, 13,864 ft (Grenadier Range) * Turret Peak, 13,835 ft * J ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mazatzal Group
The Mazatzal Group is a group of geologic formations that crops out in portions of central Arizona, US. Detrital zircon geochronology establishes a maximum age for the formation of 1660 to 1630 million years ( Mya), in the Statherian period of the Precambrian. The group gives its name to the Mazatzal orogeny, a mountain-building event that took place between 1695 and 1630 Mya. Description The Mazatzal Group consists mostly of fine-grained light-brown to gray quartzite which often shows cross-bedding; metaconglomerate containing clasts up to or more in size; and occasional lenses, up to in thickness, of maroon to gray argillite showing ripple marks and mudcracks. The lower beds of the group are intruded by rhyolite domes and sills. The total thickness of the group is up to . The group lies disconformably on top of the Red Rock Rhyolite and is in turn overlain by the Hopi Springs Shale. The group crops out in the Mazatzal Mountains, where it has been strongly deformed (with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
New Mexico
) , population_demonym = New Mexican ( es, Neomexicano, Neomejicano, Nuevo Mexicano) , seat = Santa Fe , LargestCity = Albuquerque , LargestMetro = Tiguex , OfficialLang = None , Languages = English, Spanish ( New Mexican), Navajo, Keres, Zuni , Governor = , Lieutenant Governor = , Legislature = New Mexico Legislature , Upperhouse = Senate , Lowerhouse = House of Representatives , Judiciary = New Mexico Supreme Court , Senators = * * , Representative = * * * , postal_code = NM , TradAbbreviation = N.M., N.Mex. , area_rank = 5th , area_total_sq_mi = 121,591 , area_total_km2 = 314,915 , area_land_sq_mi = 121,298 , area_land_km2 = 314,161 , area_water_sq_mi = 292 , area_water_km2 = 757 , area_water_percent = 0.24 , population_as_of = 2020 , population_rank = 36th , 2010Pop = 2,117,522 , population_density_rank = 45th , 2000DensityUS = 17.2 , 2000Density = 6.62 , MedianHouseholdIncome = $51,945 , IncomeRank = 45th , AdmittanceOrder = ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ortega Formation
The Ortega Formation is a geologic formation that crops out in most of the mountain ranges of northern New Mexico. Detrital zircon geochronology establishes a maximum age for the formation of 1690-1670 million years ( Mya), in the Statherian period of the Precambrian. Jones ''et al.'' 2011 Description The Ortega Formation consists of a very clean (98% modal quartzBauer 2004, p.198), typically bluish-white, quartzite, with some beds near the base of the formation composed of metaconglomerate. Crossbedding is found throughout the formation, and aluminosilicate minerals are abundant within the formation. These show that its lower beds were buried deeply enough to be metamorphosed to the sillimanite facies, at temperatures of over . The Ortega Formation is the principal ridge-forming formation of the Picuris Mountains and is a uniform thick. The contact between the Ortega Formation and the underlying Vadito Group is fairly easy to trace using a regional manganese-rich marker bed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Picuris Orogeny
The Picuris orogeny was an orogenic event in what is now the Southwestern United States from 1.43 to 1.3 billion years ago in the Calymmian Period of the Mesoproterozoic. The event is named for the Picuris Mountains in northern New Mexico and interpreted either as the suturing of the Granite-Rhyolite crustal province to the southern margin of the proto-North American continent Laurentia or as the final suturing of the Mazatzal crustal province onto Laurentia. According to the former hypothesis, this was the second in a series of orogenies within a long-lived convergent boundary along southern Laurentia that ended with the ca. 1200–1000 Mya Grenville orogeny during the final assembly of the supercontinent Rodinia, which ended an 800-million-year episode of convergent boundary tectonism. Description Age and isotope data show that southern North America is composed of a series of northeast-trending provinces representing island arc terranes accreted onto the 1800 Mya core of Lauren ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Detrital Zircon Geochronology
Detrital zircon geochronology is the science of analyzing the age of zircons deposited within a specific sedimentary unit by examining their inherent radioisotopes, most commonly the uranium–lead ratio. Zircon is a common accessory or trace mineral constituent of most granite and felsic igneous rocks. Due to its hardness, durability and chemical inertness, zircon persists in sedimentary deposits and is a common constituent of most sands. Zircons contain trace amounts of uranium and thorium and can be dated using several modern analytical techniques. Detrital zircon geochronology has become increasingly popular in geological studies from the 2000s mainly due to the advancement in radiometric dating techniques. Detrital zircon age data can be used to constrain the maximum depositional age, determine provenance, and reconstruct the tectonic setting on a regional scale. Detrital zircon Origin Detrital zircons are part of the sediment derived from weathering and erosion of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shale
Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4) and tiny fragments (silt-sized particles) of other minerals, especially quartz and calcite.Blatt, Harvey and Robert J. Tracy (1996) ''Petrology: Igneous, Sedimentary and Metamorphic'', 2nd ed., Freeman, pp. 281–292 Shale is characterized by its tendency to split into thin layers ( laminae) less than one centimeter in thickness. This property is called '' fissility''. Shale is the most common sedimentary rock. The term ''shale'' is sometimes applied more broadly, as essentially a synonym for mudrock, rather than in the more narrow sense of clay-rich fissile mudrock. Texture Shale typically exhibits varying degrees of fissility. Because of the parallel orientation of clay mineral flakes in shale, it breaks into thin layers, often splintery and usually parallel to the otherwise indistinguishable beddin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mudstone
Mudstone, a type of mudrock, is a fine-grained sedimentary rock whose original constituents were clays or muds. Mudstone is distinguished from '' shale'' by its lack of fissility (parallel layering).Blatt, H., and R.J. Tracy, 1996, ''Petrology.'' New York, New York, W. H. Freeman, 2nd ed, 529 pp. The term ''mudstone'' is also used to describe carbonate rocks (limestone or dolomite) that are composed predominantly of carbonate mud. However, in most contexts, the term refers to siliciclastic mudstone, composed mostly of silicate minerals. The NASA Curiosity rover has found deposits of mudstone on Mars that contain organic substances such as propane, benzene and toluene. Definition There is not a single definition of mudstone that has gained general acceptance,Boggs 2006, p.143 though there is wide agreement that mudstones are fine-grained sedimentary rocks, composed mostly of silicate grains with a grain size less than . Individual grains this size are too small to be disting ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sandstone
Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates) because they are the most resistant minerals to weathering processes at the Earth's surface. Like uncemented sand, sandstone may be any color due to impurities within the minerals, but the most common colors are tan, brown, yellow, red, grey, pink, white, and black. Since sandstone beds often form highly visible cliffs and other topographic features, certain colors of sandstone have been strongly identified with certain regions. Rock formations that are primarily composed of sandstone usually allow the percolation of water and other fluids and are porous enough to store large quantities, making them valuable aquifers and petroleum reservoirs. Quartz-bearing sandstone can be changed into quartzite through metamorphism, usually related to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rico, Colorado
Rico is an incorporated small town in Dolores County, Colorado, United States. It was settled in 1879 as a silver mining center in the Pioneer Mining District; today it functions as a historic and tourism site. The population was 265 at the 2010 census, up from 205 at the 2000 census. Its current form of government is that of a home rule municipality. Rico is a name derived from Spanish meaning "rich". Geography Rico is located in eastern Dolores County at (37.692095, -108.030839), in the valley of the Dolores River. Colorado State Highway 145 passes through the town as it follows the river, leading southwest to Cortez and northeast over Lizard Head Pass to Telluride. According to the U.S. Census Bureau, the town of Rico has an area of , all of it land. Climate Rico experiences an alpine subarctic climate (Köppen climate classification ''Dfc'') with long, cold, very snowy winters and short, cool summers due to the high altitude and high precipitation year-round due to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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