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Purcell Knob
Purcell Knob is a spur of the Blue Ridge Mountain in Loudoun County, Virginia. The peak is just northeast of the main ridge at Keyes Gap and southeast of the village of Neersville. Purcell Knob is notable for exposure of the sericitic phyllite base of the Paleozoic The Paleozoic (or Palaeozoic) Era is the earliest of three geologic eras of the Phanerozoic Eon. The name ''Paleozoic'' ( ;) was coined by the British geologist Adam Sedgwick in 1838 by combining the Greek words ''palaiós'' (, "old") and ' ... Loudoun Formation in its antiformal syncline. References Mountains of Virginia Mountains of Loudoun County, Virginia Blue Ridge Mountains {{LoudounCountyVA-geo-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 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. This 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 Ridge prov ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Appalachian Mountains
The Appalachian Mountains, often called the Appalachians, (french: Appalaches), are a system of mountains in eastern to northeastern North America. The Appalachians first formed roughly 480 million years ago during the Ordovician Period. They once reached elevations similar to those of the Alps and the Rocky Mountains before experiencing natural erosion. The Appalachian chain is a barrier to east–west travel, as it forms a series of alternating ridgelines and valleys oriented in opposition to most highways and railroads running east–west. Definitions vary on the precise boundaries of the Appalachians. The United States Geological Survey (USGS) defines the ''Appalachian Highlands'' physiographic division as consisting of 13 provinces: the Atlantic Coast Uplands, Eastern Newfoundland Atlantic, Maritime Acadian Highlands, Maritime Plain, Notre Dame and Mégantic Mountains, Western Newfoundland Mountains, Piedmont, Blue Ridge, Valley and Ridge, St. Lawrence Valley, A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Loudoun County, Virginia
Loudoun County () is in the northern part of the Commonwealth of Virginia in the United States. In 2020, the census returned a population of 420,959, making it Virginia's third-most populous county. Loudoun County's seat is Leesburg. Loudoun County is part of the Washington–Arlington–Alexandria, DC–VA–MD–WV Metropolitan Statistical Area. As of 2020, Loudoun County had a median household income of $147,111. Since 2008, the county has been ranked first in the U.S. in median household income among jurisdictions with a population of 65,000 or more. Between 1952 and 2008, Loudoun was a Republican-leaning county. However, this has changed in recent years with Democrats winning Loudoun in all statewide campaigns after 2014 and Democrats holding a two-thirds majority on the county Board of Supervisors, reflective of an ongoing realignment of affluent and college-educated voters towards the party. __TOC__ History Loudoun County was established in 1757 from Fairfax Co ... [...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 Atlantic Coast and the Appalachian Mountains. The geography and climate of the 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 Beach is the most-populous city, and 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 several indigenous groups, including the Powhatan. In 1607, the London Company established the Colony of Virginia as the first permanent English colony in the New World. Virginia's state nickname, the Old Dominion, is a reference to this status. Slave labor and land acquired from displaced native tribes fueled the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territories, nine Minor Outlying Islands, and 326 Indian reservations. The United States is also in free association with three Pacific Island sovereign states: the Federated States of Micronesia, the Marshall Islands, and the Republic of Palau. It is the world's third-largest country by both land and total area. It shares land borders with Canada to its north and with Mexico to its south and has maritime borders with the Bahamas, Cuba, Russia, and other nations. With a population of over 333 million, it is the most populous country in the Americas and the third most populous in the world. The national capital of the United States is Washington, D.C. and its most populous city and principal financial center is New York City. Paleo-Americ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blue Ridge Mountain
Blue Ridge Mountain, also known as Blue Mountain, is the colloquial name of the westernmost ridge of the Blue Ridge Mountains in northern Virginia and the Eastern Panhandle of West Virginia. The Appalachian Trail traverses the entire length of the mountain along its western slope and crest. Geography The mountain extends from the Potomac River in the north to Chester Gap in the south. Along this section of the Blue Ridge Mountains, Blue Ridge Mountain comprises the sole ridge of the chain in the immediate vicinity and contains few spur ridges or peaks. The notable exceptions are the Bull Run and Catoctin mountains, which lie approximately to the east across the Loudoun Valley, and Short Hill Mountain, located to the east, which runs parallel to the Blue Ridge for near its northern terminus. To the west of the mountain is the lower Shenandoah Valley. Blue Ridge Mountain is noticeably lower in elevation than other sections of the Blue Ridge Mountains in Virginia. The southe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Keyes Gap
Keyes Gap or Keyes' Gap is a wind gap in the Blue Ridge Mountain on the border of Loudoun County, Virginia and Jefferson County, West Virginia. The gap is traversed by Virginia State Route 9/ West Virginia Route 9. The Appalachian Trail also crosses the gap. History Originally known as Vestal's Gap, the gap is one of the lowest crossings of the Blue Ridge in Virginia. During the colonial period the main road between Alexandria and Winchester ran through the gap. As such, part of General Edward Braddock's army under George Washington crossed through the gap on their way to Fort Duquesne during the French and Indian War. By 1820, the main route west became the newly completed Snickers Gap Turnpike which crossed the Blue Ridge to the south at Snickers Gap, and Keyes Gap lost its prominence. Despite this, Keyes Gap was still of strategic importance during the American Civil War, as it provided an alternate "back route" from Virginia to the key point of Harpers Ferry. Se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neersville, Virginia
Neersville is an unincorporated community in northwestern Loudoun County, Virginia, United States. It is located in the Between the Hills area of the Loudoun Valley on Harpers Ferry Road (Virginia Secondary Route 671) at the foot of Short Hill Mountain. It is notable for being the birthplace of Confederate guerrilla John Mobberly. History Neersville derives its name from the Neer brothers, Conrad and William, who were in the 1770s the first to lease and later own the land around the present village .Mary Fishback, Thomas Balch: Loudoun County: 250 Years of Towns and Villages, Library Commission · 1999, pp. 111-11/ref> Their land deeds began in 1786. The village began to coalesce around the dependencies of the Near farms in 1834 when the Lutheran Church was given a half acre on which they constructed St. Paul's Church. Within five years, the post office established a branch in the village which they christened Neersville and, with it, the "Capitol City" of Between the Hills was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phyllite
Phyllite ( ) is a type of foliated metamorphic rock created from slate that is further metamorphosed so that very fine grained white mica achieves a preferred orientation.Stephen Marshak ''Essentials of Geology'', 3rd ed. It is primarily composed of quartz, sericite mica, and chlorite. Phyllite has fine-grained mica flakes, whereas slate Slate is a fine-grained, foliated, homogeneous metamorphic rock derived from an original shale-type sedimentary rock composed of clay or volcanic ash through low-grade regional metamorphism. It is the finest grained foliated metamorphic rock. ... has extremely fine mica flakes, and schist has large mica flakes, all mica flakes of which have achieved a preferred orientation. Among foliated metamorphic rocks, it represents a gradation in the degree of metamorphism between slate and schist. The minute crystals of graphite, sericite, or chlorite, or the translucent fine-grained white mica, impart a silky, sometimes golden sheen to the surfa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paleozoic
The Paleozoic (or Palaeozoic) Era is the earliest of three geologic eras of the Phanerozoic Eon. The name ''Paleozoic'' ( ;) was coined by the British geologist Adam Sedgwick in 1838 by combining the Greek words ''palaiós'' (, "old") and ''zōḗ'' (), "life", meaning "ancient life" ). It is the longest of the Phanerozoic eras, lasting from , and is subdivided into six geologic periods (from oldest to youngest): # Cambrian # Ordovician # Silurian # Devonian # Carboniferous # Permian The Paleozoic comes after the Neoproterozoic Era of the Proterozoic Eon and is followed by the Mesozoic Era. The Paleozoic was a time of dramatic geological, climatic, and evolutionary change. The Cambrian witnessed the most rapid and widespread diversification of life in Earth's history, known as the Cambrian explosion, in which most modern phyla first appeared. Arthropods, molluscs, fish, amphibians, reptiles, and synapsids all evolved during the Paleozoic. Life began in the oc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chilhowee Group
The Chilhowee Group is a sedimentary body composed of early Cambrian siliciclastic sedimentary rocks which crop out along the eastern margin of the Blue Ridge province in Alabama, Maryland, Tennessee, North Carolina, Virginia, and West Virginia. They represent a rift to passive margin sequence, with mostly coarse, feldspathic sandstones and conglomerates in the lower member and shales and phyllite Phyllite ( ) is a type of foliated metamorphic rock created from slate that is further metamorphosed so that very fine grained white mica achieves a preferred orientation.Stephen Marshak ''Essentials of Geology'', 3rd ed. It is primarily compo ... in the upper members. The Chilhowee Group contains four formations; the Loudoun Formation, Weverton Formation, Harpers Formation and Antietam Formation. Another name for the Harpers formations is the Hampton formation, and the Antietam Formation is also known as the Erwin Formation. The Hampton Formation has minor economic importance ... [...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 Interst ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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