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White Ledges Formation
The White Ledges Formation is a geologic formation that crops out in central Arizona, US. Detrital zircon geochronology establishes a maximum age for the formation of 1726 million years (Mya), in the Statherian period of the Precambrian. The formation is typical of quartzites deposited around 1650 million years ago in the southwestern part of Laurentia, the ancient core of the North American continent. Description The White Ledges Formation consists of of orthoquartzite. The quartzite is cut by small reverse faults dipping to the north. It is the lowest member of the Hess Canyon Group and is disconformably overlain by the Yankee Joe Formation. It overlies and interfingers with the Redmond Formation, which has been radiometrically dated as 1657 ± 3 million years old, and it contains detrital zircons dated to not less than 1726 million years old. The White Ledges Formation is thought to be sediments deposited in a nearshore tidal and fluvial environment. Together with other ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geological Formation
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 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 Abraham Gottlob Wer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laurentia
Laurentia or the North American Craton is a large continental craton that forms the ancient geological core of North America. Many times in its past, Laurentia has been a separate continent, as it is now in the form of North America, although originally it also included the cratonic areas of Greenland and also the northwestern part of Scotland, known as the Hebridean Terrane. During other times in its past, Laurentia has been part of larger continents and supercontinents and itself consists of many smaller terranes assembled on a network of Early Proterozoic orogenic belts. Small microcontinents and oceanic islands collided with and sutured onto the ever-growing Laurentia, and together formed the stable Precambrian craton seen today. The craton is named after the Laurentian Shield, through the Laurentian Mountains, which received their name from the Saint Lawrence River, named after Lawrence of Rome. Interior platform In eastern and central Canada, much of the stable craton is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Globe, Arizona
Globe ( apw, Bésh Baa Gowąh "Place of Metal") is a city in Gila County, Arizona, United States. As of the 2020 census, the population of the city was 7,249. The city is the county seat of Gila County. Globe was founded c. 1875 as a mining camp. Mining, tourism, government and retirees are most important in the present-day Globe economy. The Globe Downtown Historic District was added to the National Register of Historic Places in 1987. Geography Globe is in southern Gila County at (33.399858, −110.781570), in the valley of Pinal Creek, a north-flowing tributary of the Salt River. U.S. Route 60 passes through the city, leading northeast through the Fort Apache Indian Reservation to Show Low, and west to Phoenix. The western terminus of U.S. Route 70 is in Globe at US 60 on the east side of town; US 70 leads southeast through the San Carlos Apache Indian Reservation to Safford and to its eastern terminus at Atlantic, North Carolina. Arizona State Route 77 leads south ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salt River (Arizona)
The Salt River (Spanish: , O'odham ima , Yavapai: or , Maricopa language: Va Shly’ay) is a river in Gila and Maricopa counties in Arizona, United States, that is the largest tributary of the Gila River. The river is about 200 miles (320 km) long.Calculated with Google Maps and Google Earth Its drainage basin is about 13,700 square miles (35,000 km2) large. The longest of the Salt River's many tributaries is the 195-mile (314 km) Verde River. The Salt's headwaters tributaries, the Black River and East Fork, increase the river's total length to about 300 miles (480 km). The name Salt River comes from the fact that the river flows over large salt deposits shortly after the merging of the White and Black Rivers. Variant names According to the Geographic Names Information System, the Salt River has also been known as: * Assumption * Black River * Blau Fluss * Blue River * Rio Asuncion * Rio Azulrio de Lasrio * Rio de la Asuncion ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pinal Schist
Pinal may refer to: People *Pinal or Pinaleño, a band of the Native American Apache tribe *Silvia Pinal (born 1931), Mexican actress *Pinal Shah (born 1987), Indian World Cup wicket-keeper Places *Pinal County, Arizona, United States **Pinal Airpark, huge aircraft boneyard near Marana *Pinal City, Arizona, ghost town in Pinal County *Pinal, Arizona, census-designated place in Gila County *Pinal de Amoles Pinal de Amoles is a town located in Pinal de Amoles Municipality in the state of Querétaro in central Mexico. It is part of the Sierra Gorda region which stretches over northern Querétaro into Guanajuato, Hidalgo and San Luis Potosí, with 8 ..., Querétaro, Mexico * El Piñal, former Spanish port in Guangdong, China {{disambiguation, geo, surname ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Supercontinent
In geology, a supercontinent is the assembly of most or all of Earth's continent, continental blocks or cratons to form a single large landmass. However, some geologists use a different definition, "a grouping of formerly dispersed continents", which leaves room for interpretation and is easier to apply to Precambrian times. To separate supercontinents from other groupings, a limit has been proposed in which a continent must include at least about 75% of the continental crust then in existence in order to qualify as a supercontinent. Supercontinents have assembled and dispersed multiple times in the geologic past (see table). According to modern definitions, a supercontinent does not exist today; the closest in existence to a supercontinent is the current Afro-Eurasian landmass, which covers approx. 57% of Earth's total land area. The last time the continental landmasses were near to one another was 336 to 175 million years ago as the supercontinent, Pangaea. The positions of con ... [...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] |
Zircon
Zircon () is a mineral belonging to the group of nesosilicates and is a source of the metal zirconium. Its chemical name is zirconium(IV) silicate, and its corresponding chemical formula is Zr SiO4. An empirical formula showing some of the range of substitution in zircon is (Zr1–y, REEy)(SiO4)1–x(OH)4x–y. Zircon precipitates from silicate melts and has relatively high concentrations of high field strength incompatible elements. For example, hafnium is almost always present in quantities ranging from 1 to 4%. The crystal structure of zircon is tetragonal crystal system. The natural color of zircon varies between colorless, yellow-golden, red, brown, blue, and green. The name derives from the Persian ''zargun'', meaning "gold-hued". This word is corrupted into "jargoon", a term applied to light-colored zircons. The English word "zircon" is derived from ''Zirkon'', which is the German adaptation of this word. Yellow, orange, and red zircon is also known as "hyacinth", ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Redmond Formation
The Redmond Formation is a geologic formation in Newfoundland and Labrador. It preserves fossils dating back to the mid-Cretaceous (Cenomanian). It was a thin (up to thick) and restricted unit traced for in a single mine (Redmond No. 1) in Labrador, overlying Paleoproterozoic rocks, with large amounts of rubble, probably as a result of graben subsidence within the Labrador trough. Argillite facies within the formation have produced a diverse flora and insect assemblage.Demers Potvin & Larsson, 2019 Fossil content Mesoraphidiidae * '' Alloraphidia dorfi'' Palaeoleontidae * '' Palaeoleon ferrogeneticus'' Susumaniidae * '' Palaeopteron complexum'' Coleoptera * Coleoptera indet. Labradorocoleidae * '' Labradorocoleus carpenteri'' Cupedidae * Cupedidae indet. * Haliplidae indet. * '' Peltodytes'' sp. Tettigarctidae * '' Maculaferrum blaisi''Demers Potvin et al., 2020 Dictyoptera * '' Cretatermes carpenteri'' * ''Labradormantis'' ''guilbaulti'' See also * L ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Interfingering
A geological contact is a boundary which separates one rock body from another. A contact can be formed during deposition, by the intrusion of magma, or through faulting or other deformation of rock beds that brings distinct rock bodies into contact. The geologic subdiscipline of stratigraphy is primarily concerned with depositional contacts,Boggs 2006, p. 401 while faults and shear zones are of particular interest in structural geology. Faults and shear zones can be regarded as a form of secondary structure in the rock beds.Davis and Kluth 2011, p.21 Types of contacts Depositional Conformable Conformable contacts represent no time gap in the geologic record. They are usually planar, though they may have slightly irregular topography. These contacts represent continual, uninterrupted deposition and accumulation of sedimentary rocks, or represent lava flows. A conformable contact can be ''abrupt'', where the contact separates beds of distinct lithology. Abrupt contacts coi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Disconformity
An unconformity is a buried erosional or non-depositional surface separating two rock masses or strata of different ages, indicating that sediment deposition was not continuous. In general, the older layer was exposed to erosion for an interval of time before deposition of the younger layer, but the term is used to describe any break in the sedimentary geologic record. The significance of angular unconformity (see below) was shown by James Hutton, who found examples of Hutton's Unconformity at Jedburgh in 1787 and at Siccar Point in 1788. The rocks above an unconformity are younger than the rocks beneath (unless the sequence has been overturned). An unconformity represents time during which no sediments were preserved in a region or were subsequently eroded before the next deposition. The local record for that time interval is missing and geologists must use other clues to discover that part of the geologic history of that area. The interval of geologic time not represented is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reverse Fault
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] |
