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Mahantango Formation
The Devonian Mahantango Formation is a mapped bedrock unit in Pennsylvania, West Virginia, and Maryland. It is named for the North branch of the Mahantango Creek in Perry and Juniata counties in Pennsylvania. It is a member of the Hamilton Group, along with the underlying the Marcellus Formation Shale. South of Tuscarora Mountain in south central Pennsylvania, the lower members of this unit were also mapped as the Montebello Formation. Details of the type section and of stratigraphic nomenclature for this unit as used by the U.S. Geological Survey are available on-line at the National Geologic Map Database. Description The Mahantango Formation is a gray, brown, and olive siltstone and shale, characterized by coarsening-upward cycles. Stratigraphic Setting The Mahantango Formation is typically found conformally overlying the Marcellus Formation, and underlying the Tully Limestone (where present). The Mahantango has been divided into four members: *Tully Limestone: a fossili ... [...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] |
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 fifth-most populous state in the nation with over 13 million residents as of 2020. It is the 33rd-largest state by area and ranks ninth among all states in population density. The southeastern Delaware Valley metropolitan area comprises and surrounds Philadelphia, the state's largest and nation's sixth most populous city. Another 2.37 million reside in Greater Pittsburgh in the southwest, centered around Pittsburgh, the state's second-largest and Western Pennsylvania's largest city. The state's su ... [...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] |
USGS 2006 1237 Table2 Stratigraphy Middle Devonian
The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, and the natural hazards that threaten it. The organization's work spans the disciplines of biology, geography, geology, and hydrology. The USGS is a fact-finding research organization with no regulatory responsibility. The agency was founded on March 3, 1879. The USGS is a bureau of the United States Department of the Interior; it is that department's sole scientific agency. The USGS employs approximately 8,670 people and is headquartered in Reston, Virginia Reston is a census-designated place in Fairfax County, Virginia and a principal city of the Washington metropolitan area. As of the 2020 U.S. Census, Reston's population was 63,226. Founded in 1964, Reston was influenced by the Garden City movem .... The USGS also has major offices n ... [...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] |
Siltstone
Siltstone, also known as aleurolite, is a clastic sedimentary rock that is composed mostly of silt. It is a form of mudrock with a low clay mineral content, which can be distinguished from shale by its lack of fissility.Blatt ''et al.'' 1980, pp.381-382 Although its permeability and porosity is relatively low, siltstone is sometimes a tight gas reservoir rock, an unconventional reservoir for natural gas that requires hydraulic fracturing for economic gas production. Siltstone was prized in ancient Egypt for manufacturing statuary and cosmetic palettes. The siltstone quarried at Wadi Hammamat was a hard, fine-grained siltstone that resisted flaking and was almost ideal for such uses. Description There is not complete agreement on the definition of siltstone. One definition is that siltstone is mudrock ( clastic sedimentary rock containing at least 50% clay and silt) in which at least 2/3 of the clay and silt fraction is composed of silt-sized particles. Silt is defined a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Geological Survey
The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, and the natural hazards that threaten it. The organization's work spans the disciplines of biology, geography, geology, and hydrology. The USGS is a fact-finding research organization with no regulatory responsibility. The agency was founded on March 3, 1879. The USGS is a bureau of the United States Department of the Interior; it is that department's sole scientific agency. The USGS employs approximately 8,670 people and is headquartered in Reston, Virginia. The USGS also has major offices near Lakewood, Colorado, at the Denver Federal Center, and Menlo Park, California. The current motto of the USGS, in use since August 1997, is "science for a changing world". The agency's previous slogan, adopted on the occasion of its hundredt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pennsylvania Geological Survey
The Pennsylvania Geological Survey or Bureau of Topographic and Geologic Survey (BTGS), is a geological survey enacted by the Pennsylvania General Assembly "to serve the citizens of Pennsylvania by collecting, preserving, and disseminating impartial information on the Commonwealth's geology, geologic resources, and topography in order to contribute to the understanding, wise use, and conservation of its land and included resources." The geological survey operates under the Pennsylvania Department of Conservation and Natural Resources. History In total, four surveys have been conducted in the commonwealth. The first survey was created in 1836, making it one of the oldest geological survey A geological survey is the systematic investigation of the geology beneath a given piece of ground for the purpose of creating a geological map or model. Geological surveying employs techniques from the traditional walk-over survey, studying outc ...s in the United States. It was followed by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tuscarora Mountain
Tuscarora Mountain is a mountain ridge of the Appalachian Mountains in the Ridge and Valley province in central Pennsylvania. It reaches its highest point on Big Mountain (Pennsylvania) at above sea level. The mountain is named after the Tuscarora people. The mountain runs from northeast to southwest, extending from the Juniata River at Millerstown in the north to the end of Cove Mountain at Cowans Gap in the south. Part of it forms the border between Fulton and Franklin counties. Much of Pennsylvania State Game Lands 124 lies on Tuscarora Mountain.http://www.pgc.state.pa.us/pgc/lib/pgc/counties/maps/124.pdf Just north of Cowans Gap, the Pennsylvania Turnpike The Pennsylvania Turnpike (Penna Turnpike or PA Turnpike) is a toll highway operated by the Pennsylvania Turnpike Commission (PTC) in the U.S. state of Pennsylvania. A controlled-access highway, it runs for across the state. The turnpike's we ... traverses the ridge through the Tuscarora Mountain Tunnel. G ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Juniata County
Juniata County is a county in the Commonwealth of Pennsylvania. As of the 2020 census, the population was 23,509. Its county seat is Mifflintown. The county was created on March 2, 1831, from part of Mifflin County and named for the Juniata River. Mountains in Juniata County include Tuscarora Mountain and Shade Mountain. Agricultural land and forested land make up most of the county's area. Major rivers and creeks in the county include the Susquehanna River, the Juniata River, Tuscarora Creek, and West Branch Mahantango Creek. It borders seven other counties. The county lies over 16 different rock formations (which are from the Ordovician, Silurian, and Devonian) and 51 different soils. Juniata County has a relatively low population density. The most population-dense parts of the county are the boroughs of Mifflintown and Mifflin. The main roads in Juniata County are Pennsylvania Route 235, Pennsylvania Route 35, Pennsylvania Route 104, U.S. Route 11/U.S. Route 15, U.S. Ro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perry County, Pennsylvania
Perry County is a county in the Commonwealth of Pennsylvania. As of the 2020 census, the population was 45,842. The county seat is New Bloomfield. The county was created on March 22, 1820, and was named for Oliver Hazard Perry, a hero of the War of 1812, who had recently died. It was originally part of Cumberland County and was created in part because residents did not want to travel over the mountain to Carlisle, the county seat of Cumberland County. Landisburg became the temporary county seat before New Bloomfield was ultimately chosen. Perry County is included in the Harrisburg-Carlisle, PA Metropolitan Statistical Area. The county is served by the 717/223 area codes. In 2010, the center of population of Pennsylvania was located in the eastern end of Perry County. Green Park, an unincorporated village located in northeastern Tyrone Township, serves as Perry County's midpoint between the Conococheague Mountain in the west and the Susquehanna River to the east. Geogra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Devonian
The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, where rocks from this period were first studied. The first significant adaptive radiation of life on dry land occurred during the Devonian. Free-sporing vascular plants began to spread across dry land, forming extensive forests which covered the continents. By the middle of the Devonian, several groups of plants had evolved leaves and true roots, and by the end of the period the first seed-bearing plants appeared. The arthropod groups of myriapods, arachnids and hexapods also became well-established early in this period, after starting their expansion to land at least from the Ordovician period. Fish reached substantial diversity during this time, leading the Devonian to often be dubbed the Age of Fishes. The placoderms began dominating ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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