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Anticline
In structural geology, an anticline is a type of Fold (geology), fold that is an arch-like shape and has its oldest Bed (geology), beds at its core, whereas a syncline is the inverse of an anticline. A typical anticline is convex curve, convex up in which the hinge or crest is the location where the curvature is greatest, and the limbs are the sides of the fold that Strike and dip, dip away from the hinge. Anticlines can be recognized and differentiated from antiforms by a sequence of rock layers that become progressively older toward the center of the fold. Therefore, if age relationships between various Stratum, rock strata are unknown, the term antiform should be used. The progressing age of the rock strata towards the core and uplifted center, are the trademark indications for evidence of anticlines on a geological map. These formations occur because anticlinal ridges typically develop above thrust faults during crustal deformations. The uplifted core of the fold cau ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anticline (PSF)-vector
In structural geology, an anticline is a type of fold that is an arch-like shape and has its oldest beds at its core, whereas a syncline is the inverse of an anticline. A typical anticline is convex up in which the hinge or crest is the location where the curvature is greatest, and the limbs are the sides of the fold that dip away from the hinge. Anticlines can be recognized and differentiated from antiforms by a sequence of rock layers that become progressively older toward the center of the fold. Therefore, if age relationships between various rock strata are unknown, the term antiform should be used. The progressing age of the rock strata towards the core and uplifted center, are the trademark indications for evidence of anticlines on a geological map. These formations occur because anticlinal ridges typically develop above thrust faults during crustal deformations. The uplifted core of the fold causes compression of strata that preferentially erodes to a deeper s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anticline
In structural geology, an anticline is a type of Fold (geology), fold that is an arch-like shape and has its oldest Bed (geology), beds at its core, whereas a syncline is the inverse of an anticline. A typical anticline is convex curve, convex up in which the hinge or crest is the location where the curvature is greatest, and the limbs are the sides of the fold that Strike and dip, dip away from the hinge. Anticlines can be recognized and differentiated from antiforms by a sequence of rock layers that become progressively older toward the center of the fold. Therefore, if age relationships between various Stratum, rock strata are unknown, the term antiform should be used. The progressing age of the rock strata towards the core and uplifted center, are the trademark indications for evidence of anticlines on a geological map. These formations occur because anticlinal ridges typically develop above thrust faults during crustal deformations. The uplifted core of the fold cau ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Syncline
In structural geology, a syncline is a fold with younger layers closer to the center of the structure, whereas an anticline is the inverse of a syncline. A synclinorium (plural synclinoriums or synclinoria) is a large syncline with superimposed smaller folds. Synclines are typically a downward fold (synform), termed a synformal syncline (i.e. a trough), but synclines that point upwards can be found when strata have been overturned and folded (an antiformal syncline). Characteristics On a geologic map, synclines are recognized as a sequence of rock layers, with the youngest at the fold's center or ''hinge'' and with a reverse sequence of the same rock layers on the opposite side of the hinge. If the fold pattern is circular or elongate, the structure is a basin. Folds typically form during crustal deformation as the result of compression that accompanies orogenic mountain building. Notable examples * Powder River Basin, Wyoming, US * Sideling Hill roadcut along Inters ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Strike And Dip
In geology, strike and dip is a measurement convention used to describe the plane orientation or Attitude (geometry), attitude of a Plane (geometry), planar Geology, geologic feature. A feature's strike is the azimuth of an imagined horizontal line across the plane, and its dip is the angle of inclination (or depression angle) measured downward from horizontal. They are used together to measure and document a structure's characteristics for study or for use on a geological map. A feature's orientation can also be represented by dip and dip direction, using the azimuth of the dip rather than the strike value. Linear features are similarly measured with trend and plunge, where "trend" is analogous to dip direction and "plunge" is the dip angle. Strike and dip are measured using a compass and a clinometer. A compass is used to measure the feature's strike by holding the compass horizontally against the feature. A clinometer measures the feature's dip by recording the inclination pe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monocline
A monocline (or, rarely, a monoform) is a step-like fold in rock strata consisting of a zone of steeper dip within an otherwise horizontal or gently dipping sequence. Formation Monoclines may be formed in several different ways (see diagram) * By differential compaction over an underlying structure, particularly a large fault at the edge of a basin due to the greater compactibility of the basin fill, the amplitude of the fold will die out gradually upwards. * By mild reactivation of an earlier extensional fault during a phase of inversion causing folding in the overlying sequence. * As a form of fault propagation fold during upward propagation of an extensional fault in basement into an overlying cover sequence. * As a form of fault propagation fold during upward propagation of a reverse fault in basement into an overlying cover sequence. Examples * Waterpocket Fold in Capitol Reef National Park, Utah * Comb Ridge in southern Utah * Grandview-Phantom Monocline in Gra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fold (geology)
In structural geology, a fold is a stack of originally planar surfaces, such as sedimentary rock, sedimentary stratum, strata, that are bent or curved (''"folded"'') during permanent deformation (engineering), deformation. Folds in rocks vary in size from microscopic crinkles to mountain-sized folds. They occur as single isolated folds or in periodic sets (known as ''fold trains''). wikt:synsedimentary, Synsedimentary folds are those formed during sedimentary deposition. Folds form under varied conditions of stress (physics), stress, pore pressure, and temperature gradient, as evidenced by their presence in soft sedimentary rock, sediments, the full spectrum of metamorphic rocks, and even as primary flow structures in some igneous rocks. A set of folds distributed on a regional scale constitutes a fold belt, a common feature of orogeny, orogenic zones. Folds are commonly formed by shortening of existing layers, but may also be formed as a result of displacement on a non-planar f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blue Ridge Mountains
The Blue Ridge Mountains are a Physiographic regions of the United States, physiographic province of the larger Appalachian Highlands range. The mountain range is located in the Eastern United States and extends 550 miles southwest from southern Pennsylvania through Maryland, West Virginia, Virginia, North Carolina, South Carolina, Tennessee, and Georgia (U.S. state), Georgia. The province consists of northern and southern physiographic regions, which divide near the Roanoke River gap. To the west of the Blue Ridge, between it and the bulk of the Appalachians, lies the Great Appalachian Valley, bordered on the west by the Ridge-and-Valley Appalachians, Ridge and Valley province of the Appalachian range. The Blue Ridge Mountains are known for having a bluish color when seen from a distance. Trees put the "blue" in Blue Ridge, from the isoprene released into the atmosphere. This contributes to the characteristic haze on the mountains and their perceived color. Within the Blue Ridg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Purcell Mountains
The Purcell Mountains are a mountain range in southeastern British Columbia, Canada. They are a subrange of the Columbia Mountains, which includes the Selkirk, Monashee, and Cariboo Mountains. They are located on the west side of the Rocky Mountain Trench in the area of the Columbia Valley, and on the east side of the valley of Kootenay Lake and the Duncan River. The only large settlements in the mountains are the Panorama Ski Resort and Kicking Horse Resort, adjacent to the Columbia Valley towns of Invermere and Golden, though there are small settlements, such as Yahk and Moyie along the Crowsnest Highway, and residential rural areas dependent on the cities of Creston, Kimberley and Cranbrook, which are located adjacent to the range.. The Purcells are shown on some United States maps as the Percell Mountains, where their southern limit protrudes into the states of Idaho and Montana, abutting Lake Koocanusa, a reservoir on the Kootenai River. American geographic c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Early Cretaceous
The Early Cretaceous (geochronology, geochronological name) or the Lower Cretaceous (chronostratigraphy, chronostratigraphic name) is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 143.1 Megaannum#SI prefix multipliers, Ma to 100.5 Ma. Geology Proposals for the exact age of the Barremian–Aptian boundary ranged from 126 to 117 Ma until recently (as of 2019), but based on drillholes in Svalbard the defining Anoxic event#Cretaceous, early Aptian Oceanic Anoxic Event 1a (OAE1a) was dated to 123.1±0.3 Ma, limiting the possible range for the boundary to c. 122–121 Ma. There is a possible link between this anoxic event and a series of Early Cretaceous large igneous provinces (LIP). The Ontong Java Plateau, Ontong Java-Manihiki Plateau, Manihiki-Hikurangi Plateau, Hikurangi large igneous province, emplaced in the South Pacific at c. 120 Ma, is by far the largest LIP in Earth's history. The Onto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nittany Valley
Nittany Valley is an erosion, eroded anticline, anticlinal valley located in Centre County, Pennsylvania, Centre County, Pennsylvania. It is separated from the Bald Eagle Valley by Bald Eagle Mountain and from Penns Valley by Mount Nittany. The valley is closed to the north by a high plateau that joins these two mountain ridges, but is open to the south at the southern terminus of Mount Nittany. The valley drains to Bald Eagle Creek (West Branch Susquehanna River), Bald Eagle Creek through water gaps in Bald Eagle Mountain formed by Spring Creek (Bald Eagle Creek), Spring Creek and Fishing Creek (Bald Eagle Creek), Fishing Creek, along with smaller streams running through Curtain Gap and Howard Gap. The northwest side of the valley between the Bald Eagle Mountain ridge and the lower Sand Ridge is also known as the Little Nittany Valley. The valley has a mixture of farmland, woodlots, and several working and abandoned quarries. Bellefonte, Pennsylvania, Bellefonte, the county seat o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Late Jurassic
The Late Jurassic is the third Epoch (geology), epoch of the Jurassic Period, and it spans the geologic time scale, geologic time from 161.5 ± 1.0 to 143.1 ± 0.8 million years ago (Ma), which is preserved in Upper Jurassic stratum, strata.Owen 1987. In European lithostratigraphy, the name "Malm" indicates rocks of Late Jurassic age. In the past, ''Malm'' was also used to indicate the unit of geological time, but this usage is now discouraged to make a clear distinction between lithostratigraphic and geochronologic/chronostratigraphic units. Subdivisions The Late Jurassic is divided into three ages, which correspond with the three (faunal) stages of Upper Jurassic rock: Paleogeography During the Late Jurassic Epoch, Pangaea broke up into two supercontinents, Laurasia to the north, and Gondwana to the south. The result of this break-up was the emergence of the Atlantic Ocean, which initially was relatively narrow. Life forms This epoch is well known for many famous types of d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Richat Structure
The Richat Structure, or ''Guelb er Richât'' (, ), is a prominent circular geological feature in the Adrar Plateau of the Sahara The Sahara (, ) is a desert spanning across North Africa. With an area of , it is the largest hot desert in the world and the list of deserts by area, third-largest desert overall, smaller only than the deserts of Antarctica and the northern Ar .... It is located near Ouadane in the Adrar Region of Mauritania. In Hassaniya Arabic, ''rīšāt'' means ''feathers'' and it is also known locally in Arabic as ''tagense'', referring to the circular opening of the leather pouch that is used to draw water from local wells. It is an eroded Dome (geology), geological dome, in diameter, caused by a subsurface igneous intrusion deforming the overlying sedimentary rock layers, causing the rock to be exposed as concentric rings with the oldest layers exposed at the centre of the structure. Igneous rock is exposed inside and there are rhyolites and gabbros tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
