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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] |
Group (stratigraphy)
In geology, a group is a lithostratigraphy, lithostratigraphic Stratigraphic unit, unit consisting of a series of related Geological formation, formations that have been classified together to form a group. Formations are the fundamental unit of stratigraphy. Groups may sometimes be combined into Supergroup (geology), supergroups. Groups are useful for showing relationships between formations, and they are also useful for small-scale mapping or for studying the stratigraphy of large regions. Geologists exploring a new area have sometimes defined groups when they believe the strata within the groups can be divided into formations during subsequent investigations of the area. It is possible for only some of the strata making up a group to be divided into formations. An example of a group is the Glen Canyon Group, which includes (in ascending order) the Wingate Sandstone, the Moenave Formation, the Kayenta Formation, and the Navajo Sandstone. Each of the formations can be distingui ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metaconglomerate
Metaconglomerate is a rock type which originated from conglomerate after undergoing metamorphism. Conglomerate is easily identifiable by the pebbles or larger clasts in a matrix of sand, silt, or clay. Metaconglomerate looks similar to conglomerate, although sometimes the clasts are deformed. The cement matrix of conglomerate is not as durable as the grains, and hence when broken, conglomerate breaks around the grains. Metaconglomerate, however, breaks through the grains, as the cement has recrystallized and may be as durable as the clasts. Foliated metaconglomerate is created under the same metamorphic conditions that produce slate or phyllite, but with the parent rock (protolith) being conglomerate, rather than clay.Essentials of Geology, 3rd Ed, Stephen Marshak The metaconglomerates of the Jack Hills of Western Australia are the source rocks for much of the detrital zircon Zircon () is a mineral belonging to the group of nesosilicates and is a source of the metal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Four Peaks Quartzite
4 (four) is a number, numeral and digit. It is the natural number following 3 and preceding 5. It is a square number, the smallest semiprime and composite number, and is considered unlucky in many East Asian cultures. Evolution of the Hindu-Arabic digit Brahmic numerals represented 1, 2, and 3 with as many lines. 4 was simplified by joining its four lines into a cross that looks like the modern plus sign. The Shunga would add a horizontal line on top of the digit, and the Kshatrapa and Pallava evolved the digit to a point where the speed of writing was a secondary concern. The Arabs' 4 still had the early concept of the cross, but for the sake of efficiency, was made in one stroke by connecting the "western" end to the "northern" end; the "eastern" end was finished off with a curve. The Europeans dropped the finishing curve and gradually made the digit less cursive, ending up with a digit very close to the original Brahmin cross. While the shape of the character for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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] |
Maverick Shale
Maverick or Maveric may refer to: History * Maverick (animal), an unbranded range animal, derived from U.S. cattleman Samuel Maverick Aviation * AEA Maverick, an Australian single-seat sportsplane design * General Aviation Design Bureau T-32 Maverick, a Ukrainian ultralight trike design * I-Fly Maverick, a US powered-parachute flying vehicle under development by the Indigenous People's Technology and Education Center * Murphy Maverick, a Canadian light aircraft design * AGM-65 Maverick, a US guided air-to-surface missile * Airbus MAVERIC, a European sub-scale blended wing body prototype Computing * Maverick Framework, a model-view-controller framework for Java * Maverick Meerkat, the version 10.10 of Ubuntu * OS X Mavericks, the tenth major release of Apple's OS X operating system Film and television * ''The Maverick'', a 1952 Western film starring Wild Bill Elliott * ''Maverick'' (TV series), an American western series starring James Garner and Jack Kelly ** ''Maverick'' (f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deadman Quartzite
Deadman or Deadman's may refer to: * "Deadman" or "dead man", are alternative terms for a dead man's switch * "Deadman's foot" is another name for a Salamander in metallurgy * "Deadman anchor" is a buried object (log, concrete, block, etc.) used to anchor objects during construction, mooring, or other activities. ** Deadman (climbing), an anchor used in Alpine mountaineering, such as a snow fluke Places * Deadman's Cay, Bahamas ** Deadman's Cay Airport, an airport on the aforementioned cay * ''Deadman's Curve'', a 1978 American made-for-television biographical film * Deadman Islands * Deadman's Island (other), a number of places of the same name ** Deadman's Island, Halifax ** Deadman's Island (San Pedro) ** Deadman's Island (Vancouver) * Deadman SSSI, Somerset * Deadman Summit, California * Deadman River, British Columbia People * Derek Deadman (1940–2014), English actor * The Undertaker (born 1965), professional wrestler, also known as The Deadman Media ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metamorphism
Metamorphism is the transformation of existing Rock (geology), rock (the protolith) to rock with a different mineral composition or Texture (geology), texture. Metamorphism takes place at temperatures in excess of , and often also at elevated pressure or in the presence of chemically active fluids, but the rock remains mostly solid during the transformation. Metamorphism is distinct from weathering or diagenesis, which are changes that take place at or just beneath Earth's surface. Various forms of metamorphism exist, including Regional metamorphism, regional, Contact metamorphism, contact, Hydrothermal metamorphism, hydrothermal, Shock metamorphism, shock, and Dynamic metamorphism, dynamic metamorphism. These differ in the characteristic temperatures, pressures, and rate at which they take place and in the extent to which reactive fluids are involved. Metamorphism occurring at increasing pressure and temperature conditions is known as ''prograde metamorphism'', while decreasin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Disconformity
An unconformity is a buried erosion surface, erosional or non-depositional surface separating two Rock (geology), rock masses or Stratum, 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 rocks, 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 Berwickshire in 1788, both in Scotland. The rocks above an unconformity Law of superposition, are younger than the rocks beneath (unless the sequence has been overturned). An unconformity represents Geologic time, 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 m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sill (geology)
In geology, a sill is a tabular sheet intrusion that has intruded between older layers of sedimentary rock, beds of volcanic lava or tuff, or along the direction of foliation in metamorphic rock. A sill is a ''concordant intrusive sheet'', meaning that it does not cut across preexisting rock beds. Stacking of sills builds a sill complex. and a large magma chamber at high magma flux. In contrast, a dike is a discordant intrusive sheet, which does cut across older rocks. Formation Sills are fed by dikes, except in unusual locations where they form in nearly vertical beds attached directly to a magma source. The rocks must be brittle and fracture to create the planes along which the magma intrudes the parent rock bodies, whether this occurs along preexisting planes between sedimentary or volcanic beds or weakened planes related to foliation in metamorphic rock. These planes or weakened areas allow the intrusion of a thin sheet-like body of magma paralleling the existi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcanic Dome
In volcanology, a lava dome is a circular, mound-shaped protrusion resulting from the slow extrusion of viscous lava from a volcano. Dome-building eruptions are common, particularly in convergent plate boundary settings. Around 6% of eruptions on Earth form lava domes. The geochemistry of lava domes can vary from basalt (e.g. Semeru, 1946) to rhyolite (e.g. Chaiten, 2010) although the majority are of intermediate composition (such as Santiaguito, dacite-andesite, present day). The characteristic dome shape is attributed to high viscosity that prevents the lava from flowing very far. This high viscosity can be obtained in two ways: by high levels of silica in the magma, or by degassing of fluid magma. Since viscous basaltic and andesitic domes weather fast and easily break apart by further input of fluid lava, most of the preserved domes have high silica content and consist of rhyolite or dacite. Existence of lava domes has been suggested for some domed structures on the Moon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhyolite
Rhyolite ( ) is the most silica-rich of volcanic rocks. It is generally glassy or fine-grained (aphanitic) in texture (geology), texture, but may be porphyritic, containing larger mineral crystals (phenocrysts) in an otherwise fine-grained matrix (geology), groundmass. The mineral assemblage is predominantly quartz, sanidine, and plagioclase. It is the extrusive equivalent of granite. Its high silica content makes rhyolitic magma extremely viscosity, viscous. This favors explosive eruptions over effusive eruptions, so this type of magma is more often erupted as pyroclastic rock than as lava flows. Rhyolitic ash-flow tuffs are among the most voluminous of continental igneous rock formations. Rhyolitic tuff has been used extensively for construction. Obsidian, which is rhyolitic volcanic glass, has been used for tools from prehistoric times to the present day because it can be shaped to an extremely sharp edge. Rhyolitic pumice finds use as an abrasive, in concrete, and as a soil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mudcracks
Mudcracks (also known as mud cracks, desiccation cracks or cracked mud) are sedimentary structures formed as muddy sediment dries and contracts.Jackson, J.A., 1997, ''Glossary of Geology'' (4th ed.), American Geological Institute, Alexandria, VA, 769 p.Stow, D.A., 2005, ''Sedimentary Rocks in the Field'', Academic Press, London, 320 p. Crack formation also occurs in clay-bearing soils as a result of a reduction in water content. Formation of mudcrack Naturally forming mudcracks start as wet, muddy sediment dries up and contracts. A strain is developed because the top layer shrinks while the material below stays the same size. When this strain becomes large enough, channel cracks form in the dried-up surface to relieve the strain. Individual cracks spread and join up, forming a polygonal, interconnected network of forms called "tesselations." If the strain continues to build, the polygons start to curl upwards. This characteristic can be used in geology to understand the origi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
