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Weverton Formation
The Weverton Formation is a quartzite geologic formation in Maryland, Virginia, West Virginia, and Pennsylvania. It is considered the basal member of the Chilhowee Group. The Weverton Formation dates back to the Cambrian period. Description The Weverton Formation is composed of three members: the Buzzard Knob Member, Maryland Heights Member, and Owens Creek Member. The Buzzard Knob member is a coarse-grained quartzite with pervasive cross-beds. The Maryland Heights member consists of metamorphosed siltstone, coarse-grained metamorphosed greywacke, and quartzite. The Owens Creek Member is a coarse-grained to conglomeratic metamorphosed greywacke. The formation was deposited in an alluvial environment. The Weverton Formation is considered the main ridge forming unit in the Blue Ridge Mountains The Blue Ridge Mountains are a Physiographic regions of the world, physiographic province of the larger Appalachian Mountains range. The mountain range is located in the Eastern United St ... [...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 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 W ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Catoctin Formation
The Catoctin Formation is a geologic formation that expands through Virginia, Maryland, and Pennsylvania. It dates back to the Precambrian and is closely associated with the Harpers Formation, Weverton Formation, and the Loudoun Formation. The Catoctin Formation lies over the a granite basement rock and below the Chilhowee Group making it only exposed on the outer parts of the Blue Ridge. The Catoctin Formation contains metabasalt, metarhyolite, and porphyritic rocks, columnar jointing, low-dipping primary joints, amygdules, sedimentary dikes, and flow breccias. Evidence for past volcanic activity includes columnar basalts and greenstone dikes. Stratigraphy Stratigraphy of the Catoctin Formation is closely related to the Harpers Formation, Weverton Formation, and the Loudon Formation. The Harpers Formation is part of the Chilhowee Group. This formation is found above the Weverton Formation and is around 2000–2750 feet in thickness. This formation contains gray phyllite a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conglomerate (geology)
Conglomerate () is a clastic sedimentary rock that is composed of a substantial fraction of rounded to subangular gravel-size clasts. A conglomerate typically contains a matrix of finer-grained sediments, such as sand, silt, or clay, which fills the interstices between the clasts. The clasts and matrix are typically cemented by calcium carbonate, iron oxide, silica, or hardened clay. Conglomerates form by the consolidation and lithification of gravel. They can be found in sedimentary rock sequences of all ages but probably make up less than 1 percent by weight of all sedimentary rocks. In terms of origin and depositional mechanisms, they are closely related to sandstones and exhibit many of the same types of sedimentary structures, e.g., tabular and trough cross-bedding and graded bedding.Boggs, S. (2006) ''Principles of Sedimentology and Stratigraphy.'', 2nd ed. Prentice Hall, New York. 662 pp. Friedman, G.M. (2003) ''Classification of sediments and sedimentary rocks ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Greywacke
Greywacke or graywacke ( German ''grauwacke'', signifying a grey, earthy rock) is a variety of sandstone generally characterized by its hardness, dark color, and poorly sorted angular grains of quartz, feldspar, and small rock fragments or lithic fragments set in a compact, clay-fine matrix. It is a texturally immature sedimentary rock generally found in Paleozoic strata. The larger grains can be sand- to gravel-sized, and matrix materials generally constitute more than 15% of the rock by volume. The term "greywacke" can be confusing, since it can refer to either the immature (rock fragment) aspect of the rock or its fine-grained (clay) component. The origin of greywacke was unknown until turbidity currents and turbidites were understood, since, according to the normal laws of sedimentation, gravel, sand and mud should not be laid down together. Geologists now attribute its formation to submarine avalanches or strong turbidity currents. These actions churn sediment and ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Period (geology)
The geologic time scale, or geological time scale, (GTS) is a representation of time based on the rock record of Earth. It is a system of chronological dating that uses chronostratigraphy (the process of relating strata to time) and geochronology (scientific branch of geology that aims to determine the age of rocks). It is used primarily by Earth scientists (including geologists, paleontologists, geophysicists, geochemists, and paleoclimatologists) to describe the timing and relationships of events in geologic history. The time scale has been developed through the study of rock layers and the observation of their relationships and identifying features such as lithologies, paleomagnetic properties, and fossils. The definition of standardized international units of geologic time is the responsibility of the International Commission on Stratigraphy (ICS), a constituent body of the International Union of Geological Sciences (IUGS), whose primary objective is to precisely ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Formation (geology)
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 W ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
West Virginia
West Virginia is a state in the Appalachian, Mid-Atlantic and Southeastern regions of the United States.The Census Bureau and the Association of American Geographers classify West Virginia as part of the Southern United States while the Bureau of Labor Statistics classifies the state as a part of the Mid-Atlantic regionMid-Atlantic Home : Mid-Atlantic Information Office: U.S. Bureau of Labor Statistics" www.bls.gov. Archived. It is bordered by Pennsylvania to the north and east, Maryland to the east and northeast, Virginia to the southeast, Kentucky to the southwest, and Ohio to the northwest. West Virginia is the 10th-smallest state by area and ranks as the 12th-least populous state, with a population of 1,793,716 residents. The capital and largest city is Charleston. West Virginia was admitted to the Union on June 20, 1863, and was a key border state during the American Civil War. It was the only state to form by separating from a Confederate state, the second to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virginia
Virginia, officially the Commonwealth of Virginia, is a state in the Mid-Atlantic and Southeastern regions of the United States, between the East Coast of the United States, Atlantic Coast and the Appalachian Mountains. The geography and climate of the Commonwealth (U.S. state), Commonwealth are shaped by the Blue Ridge Mountains and the Chesapeake Bay, which provide habitat for much of its flora and fauna. The capital of the Commonwealth is Richmond, Virginia, Richmond; Virginia Beach, Virginia, Virginia Beach is the most-populous city, and Fairfax County, Virginia, Fairfax County is the most-populous political subdivision. The Commonwealth's population was over 8.65million, with 36% of them living in the Baltimore–Washington metropolitan area. The area's history begins with Native American tribes in Virginia, several indigenous groups, including the Powhatan. In 1607, the London Company established the Colony of Virginia as the first permanent English overseas posse ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pennsylvania
Pennsylvania (; (Pennsylvania Dutch: )), officially the Commonwealth of Pennsylvania, is a state spanning the Mid-Atlantic, Northeastern, Appalachian, and Great Lakes regions of the United States. It borders Delaware to its southeast, Maryland to its south, West Virginia to its southwest, Ohio to its west, Lake Erie and the Canadian province of Ontario to its northwest, New York to its north, and the Delaware River and New Jersey to its east. Pennsylvania is the List of U.S. states and territories by population, fifth-most populous state in the nation with over 13 million residents 2020 United States census, as of 2020. It is the List of U.S. states and territories by area, 33rd-largest state by area and ranks List of states and territories of the United States by population density, ninth among all states in population density. The southeastern Delaware Valley metropolitan area comprises and surrounds Philadelphia, the state's List of cities in Pennsylvania, largest ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maryland
Maryland ( ) is a U.S. state, state in the Mid-Atlantic (United States), Mid-Atlantic region of the United States. It shares borders with Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; and Delaware and the Atlantic Ocean to its east. Baltimore is the largest city in the state, and the capital is Annapolis, Maryland, Annapolis. Among its occasional nicknames are ''Maryland 400, Old Line State'', the ''Free State'', and the ''Chesapeake Bay State''. It is named after Henrietta Maria, the French-born queen of England, Scotland, and Ireland, who was known then in England as Mary. Before its coastline was explored by Europeans in the 16th century, Maryland was inhabited by several groups of Native Americans – mostly by Algonquian peoples and, to a lesser degree, Iroquoian peoples, Iroquoian and Siouan languages, Siouan. As one of the original Thirteen Colonies of England, Maryland was founded by George Calvert, 1st Baron Ba ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
London Conglomerate
London is the capital and List of urban areas in the United Kingdom, largest city of England and the United Kingdom, with a population of just under 9 million. It stands on the River Thames in south-east England at the head of a estuary down to the North Sea, and has been a major settlement for two millennia. The City of London, its ancient core and financial centre, was founded by the Roman Empire, Romans as ''Londinium'' and retains its medieval boundaries.See also: Independent city#National capitals, Independent city § National capitals The City of Westminster, to the west of the City of London, has for centuries hosted the national Government of the United Kingdom, government and Parliament of the United Kingdom, parliament. Since the 19th century, the name "London" has also referred to the metropolis around this core, historically split between the Counties of England, counties of Middlesex, Essex, Surrey, Kent, and Hertfordshire, which largely comprises Greater London ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Harpers Formation
The Harpers Formation is a geologic formation in Maryland, Pennsylvania, Virginia, and West Virginia, consisting of schist, phyllite, and shale. It dates back to the early Cambrian period. It is considered part of the Chilhowee Group. Notable exposures The type section is in gorges of the Potomac River and the Shenandoah River at Harpers Ferry, West Virginia. The Harpers Formation overlies the Ledger Formation ( dolomite) due to a thrust fault in small roadside quarry (currently overgrown) on Pottery Hill, southwest of York, Pennsylvania. A. J. Stose and G. W. Stose, 1944. ''Geology of the Hanover-York district'', U. S. Geological Survey Professional paper 204. Gallery File:Quartzite (Harpers Formation, Lower Cambrian; Verona, Virginia, USA).jpg, Quartzite sample of Harpers Formation from near Verona, Virginia File:Jefferson Rock, Harpers Ferry, WV - area view.jpg, Harpers Shale by Jefferson Rock in Harpers Ferry, West Virginia Harpers Phyllite Pottery Hill outcrop 2022.jpg, S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
