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110-718: Shenandoah National Park / ˈ ʃ ɛ n ə n ˌ d oʊ ə / (often / ˈ ʃ æ n ə n ˌ d oʊ ə / ) is a national park of the United States that encompasses part of the Blue Ridge Mountains in Virginia . The park is long and narrow, with the Shenandoah River and its broad valley to the west, and the rolling hills of the Virginia Piedmont to the east. Skyline Drive is

220-553: A temperate broadleaf and mixed forest . Pines predominate on the southwestern faces of some of the southernmost hillsides, where an occasional prickly pear cactus may also grow naturally. In contrast, some of the northeastern aspects are most likely to have small but dense stands of moisture loving hemlocks and mosses in abundance. Other commonly found plants include oak, hickory , chestnut , maple , tulip poplar , mountain laurel , milkweed , daisies , and many species of ferns . The once predominant American chestnut tree

330-523: A 70 ft (21 m) cascade . The distance from the trailhead to the base of the falls is 0.7 mi (1.1 km), although the trail continues beyond that point, crossing the creek and connecting with the Rose River fire road. Various fauna can be viewed along the trail, including occasional sightings of black bears and timber rattlesnakes . While the trail is relatively short, parts of it are steep and may prove challenging to some visitors. There

440-453: A broad range of opportunities for public enjoyment, recreation, inspiration, and stewardship. The park encompasses parts of eight counties. On the west side of Skyline Drive they are, from northeast to southwest, Warren , Page , Rockingham , and Augusta counties. On the east side of Skyline Drive they are Rappahannock , Madison , Greene , and Albemarle counties. The park stretches for 105 miles (169 km) along Skyline Drive from near

550-448: A concessionaire in 1937. Carson also donated significant land; a mountain in the park is now named in his honor and signs acknowledge his contributions. The last grandmother resident was Annie Lee Bradley Shenk. NPS employees had watched and cared for her since 1950; she died in 1979 at age 92. Most others left quietly. 85-year-old Hezekiah Lam explained, "I ain't so crazy about leavin' these hills but I never believed in bein' ag'in (against)

660-593: A cover sequence of metamorphosed Neoproterozoic (570–550 million years old) sedimentary and volcanic rocks of the Swift Run and Catoctin formations . Columns of Catoctin Formation metamorphosed basalt can be seen at Compton Peak. Clastic rocks of the Chilhowee Group are of early Cambrian age (542–520 million years old). Quaternary surficial deposits are common and cover much of

770-552: A descendant's organization known as the Children of Shenandoah, which resulted in the removal of questionable interpretive displays. Hikes and tours that explained the social history of the displaced mountain people began. The park is best known for Skyline Drive, a 105-mile (169 km) road that runs the length of the park along the ridge of the mountains. 101 miles (163 km) of the Appalachian Trail are also in

880-588: A dissected limestone pavement . This process is most effective along the joints, widening and deepening them. In unpolluted environments, the pH of rainwater due to dissolved carbon dioxide is around 5.6. Acid rain occurs when gases such as sulfur dioxide and nitrogen oxides are present in the atmosphere. These oxides react in the rain water to produce stronger acids and can lower the pH to 4.5 or even 3.0. Sulfur dioxide , SO 2 , comes from volcanic eruptions or from fossil fuels, and can become sulfuric acid within rainwater, which can cause solution weathering to

990-412: A maximum of 521,000 acres (814.1 sq mi; 2,108.4 km) to form Shenandoah National Park, and also authorized creation of Great Smoky Mountains National Park . However, the legislation also required that no federal funds would be used to acquire the land. Thus, Virginia needed to raise private funds, and could also authorize state funds and use its eminent domain (condemnation) power to acquire

1100-691: A mineral crystal exposes ions whose electrical charge attracts water molecules. Some of these molecules break into H+ that bonds to exposed anions (usually oxygen) and OH- that bonds to exposed cations. This further disrupts the surface, making it susceptible to various hydrolysis reactions. Additional protons replace cations exposed on the surface, freeing the cations as solutes. As cations are removed, silicon-oxygen and silicon-aluminium bonds become more susceptible to hydrolysis, freeing silicic acid and aluminium hydroxides to be leached away or to form clay minerals. Laboratory experiments show that weathering of feldspar crystals begins at dislocations or other defects on

1210-418: A more humid chemical microenvironment. The attachment of these organisms to the rock surface enhances physical as well as chemical breakdown of the surface microlayer of the rock. Lichens have been observed to pry mineral grains loose from bare shale with their hyphae (rootlike attachment structures), a process described as plucking , and to pull the fragments into their body, where the fragments then undergo

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1320-570: A popular comic strip Li'l Abner and his fictional community, Dogpatch . In 1933, Sherman and journalist Thomas Henry published Hollow Folk drawing pitying eyes to local conditions and "hillbillies." As in many rural areas of the time, most remote homesteads in the Shenandoah lacked electricity and often running water, as well as access to schools and health facilities during many months. However, Hoover had hired experienced rural teacher Christine Vest to teach near his summer home (and who believed

1430-403: A process of chemical weathering not unlike digestion. On a larger scale, seedlings sprouting in a crevice and plant roots exert physical pressure as well as providing a pathway for water and chemical infiltration. Most rock forms at elevated temperature and pressure, and the minerals making up the rock are often chemically unstable in the relatively cool, wet, and oxidizing conditions typical of

1540-478: A report about the conditions in which they lived. Although later discredited, the report depicted the local population as very poor and inbred and was soon used to support forcible evictions and burning of former cabins so residents would not sneak back. University of Chicago sociologists Fay-Cooper Cole and Mandel Sherman described how the small valley communities or hollows had existed "without contact with law or government" for centuries, which some analogized to

1650-477: A result, thermal stress weathering is sometimes called insolation weathering , but this is misleading. Thermal stress weathering can be caused by any large change of temperature, and not just intense solar heating. It is likely as important in cold climates as in hot, arid climates. Wildfires can also be a significant cause of rapid thermal stress weathering. The importance of thermal stress weathering has long been discounted by geologists, based on experiments in

1760-407: A slower reaction kinetics , this process is thermodynamically favored at low temperature, because colder water holds more dissolved carbon dioxide gas (due to the retrograde solubility of gases). Carbonate dissolution is therefore an important feature of glacial weathering. Carbonate dissolution involves the following steps: Carbonate dissolution on the surface of well-jointed limestone produces

1870-469: A threat to the environment and occupant safety. Design strategies can moderate the impact of environmental effects, such as using of pressure-moderated rain screening, ensuring that the HVAC system is able to effectively control humidity accumulation and selecting concrete mixes with reduced water content to minimize the impact of freeze-thaw cycles. Granitic rock, the most abundant crystalline rock exposed at

1980-583: A vacation fishing camp near the headwaters of the Rapidan River (and would ultimately donate it to the park as he left office; it remains as Rapidan Camp ). The commonwealth of Virginia slowly acquired the land through eminent domain , eventually giving it to the U.S. federal government to establish the national park. Carson's brother suggested that Virginia's legislature authorize condemnation by counties (followed by arbitration for individual parcels) rather than condemn each parcel. Some families accepted

2090-540: Is Gateway Arch National Park , Missouri , at 192.83 acres (0.7804 km ). The total area protected by national parks is approximately 52.4 million acres (212,000 km ), for an average of 833 thousand acres (3,370 km ) but a median of only 220 thousand acres (890 km ). The national parks set a visitation record in 2021, with more than 92 million visitors. Great Smoky Mountains National Park in North Carolina and Tennessee has been

2200-426: Is acid hydrolysis , in which protons (hydrogen ions), which are present in acidic water, attack chemical bonds in mineral crystals. The bonds between different cations and oxygen ions in minerals differ in strength, and the weakest will be attacked first. The result is that minerals in igneous rock weather in roughly the same order in which they were originally formed ( Bowen's Reaction Series ). Relative bond strength

2310-550: Is 14 megapascals (2,000 psi). This is still much greater than the tensile strength of granite, which is about 4 megapascals (580 psi). This makes frost wedging, in which pore water freezes and its volumetric expansion fractures the enclosing rock, appear to be a plausible mechanism for frost weathering. Ice will simply expand out of a straight open fracture before it can generate significant pressure. Thus, frost wedging can only take place in small tortuous fractures. The rock must also be almost completely saturated with water, or

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2420-476: Is 6a with an average annual extreme minimum temperature of -7.1 °F (-21.7 °C). The climate of the park and its flora and fauna are typical for mountainous regions of the eastern Mid-Atlantic woodland, while a large portion of common species are also typical of ecosystems at lower altitudes. A. W. Kuchler 's potential natural vegetation type for the park is Appalachian oak ( 104 ) within an eastern hardwood forest vegetation form ( 25 ), also known as

2530-403: Is a less well characterized mechanism of physical weathering. It takes place because ice grains always have a surface layer, often just a few molecules thick, that resembles liquid water more than solid ice, even at temperatures well below the freezing point. This premelted liquid layer has unusual properties, including a strong tendency to draw in water by capillary action from warmer parts of

2640-603: Is a result of differential erosion during the Cenozoic , although some post-Paleozoic tectonic activity occurred in the region. Legislation to create a national park in the Appalachian mountains was first introduced by freshman Virginia congressman Henry D. Flood in 1901, but despite the support of President Theodore Roosevelt , failed to pass. The first national park was Yellowstone, in Wyoming, Montana, and Idaho. It

2750-440: Is also important, acting to oxidize many minerals, as is carbon dioxide, whose weathering reactions are described as carbonation . The process of mountain block uplift is important in exposing new rock strata to the atmosphere and moisture, enabling important chemical weathering to occur; significant release occurs of Ca and other ions into surface waters. Dissolution (also called simple solution or congruent dissolution )

2860-715: Is also known as sheeting . As with thermal weathering, pressure release is most effective in buttressed rock. Here the differential stress directed toward the unbuttressed surface can be as high as 35 megapascals (5,100 psi), easily enough to shatter rock. This mechanism is also responsible for spalling in mines and quarries, and for the formation of joints in rock outcrops. Retreat of an overlying glacier can also lead to exfoliation due to pressure release. This can be enhanced by other physical wearing mechanisms. Salt crystallization (also known as salt weathering , salt wedging or haloclasty ) causes disintegration of rocks when saline solutions seep into cracks and joints in

2970-612: Is chemically weathered to iron(II) sulfate and gypsum , which then crystallize as salt lenses. Salt crystallization can take place wherever salts are concentrated by evaporation. It is thus most common in arid climates where strong heating causes strong evaporation and along coasts. Salt weathering is likely important in the formation of tafoni , a class of cavernous rock weathering structures. Living organisms may contribute to mechanical weathering, as well as chemical weathering (see § Biological weathering below). Lichens and mosses grow on essentially bare rock surfaces and create

3080-577: Is in equilibrium with kaolinite. Soil formation requires between 100 and 1,000 years, a brief interval in geologic time. As a result, some formations show numerous paleosol (fossil soil) beds. For example, the Willwood Formation of Wyoming contains over 1,000 paleosol layers in a 770 meters (2,530 ft) section representing 3.5 million years of geologic time. Paleosols have been identified in formations as old as Archean (over 2.5 billion years in age). They are difficult to recognize in

3190-472: Is likely the more important mechanism in nature. Geomorphologists have begun to reemphasize the importance of thermal stress weathering, particularly in cold climates. Pressure release or unloading is a form of physical weathering seen when deeply buried rock is exhumed . Intrusive igneous rocks, such as granite , are formed deep beneath the Earth's surface. They are under tremendous pressure because of

3300-530: Is no view from the brink of the falls, and slippery rocks make it inadvisable to leave the trail. According to the Köppen climate classification system, Shenandoah National Park has a humid continental climate with warm summers and no dry season ( Dfb ). According to the United States Department of Agriculture , the plant hardiness zone at Big Meadows Visitor Center (3514 ft / 1071 m)

3410-484: Is relatively poor in potassium, the basalt weathers directly to potassium-poor montmorillonite , then to kaolinite . Where leaching is continuous and intense, as in rain forests, the final weathering product is bauxite , the principal ore of aluminium. Where rainfall is intense but seasonal, as in monsoon climates, the final weathering product is iron- and titanium-rich laterite . Conversion of kaolinite to bauxite occurs only with intense leaching, as ordinary river water

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3520-449: Is shown in the following table: This table is only a rough guide to order of weathering. Some minerals, such as illite , are unusually stable, while silica is unusually unstable given the strength of the silicon–oxygen bond . Carbon dioxide that dissolves in water to form carbonic acid is the most important source of protons, but organic acids are also important natural sources of acidity. Acid hydrolysis from dissolved carbon dioxide

3630-421: Is sometimes described as carbonation , and can result in weathering of the primary minerals to secondary carbonate minerals. For example, weathering of forsterite can produce magnesite instead of brucite via the reaction: Carbonic acid is consumed by silicate weathering, resulting in more alkaline solutions because of the bicarbonate . This is an important reaction in controlling the amount of CO 2 in

3740-410: Is the class of processes that causes the disintegration of rocks without chemical change. Physical weathering involves the breakdown of rocks into smaller fragments through processes such as expansion and contraction, mainly due to temperature changes. Two types of physical breakdown are freeze-thaw weathering and thermal fracturing. Pressure release can also cause weathering without temperature change. It

3850-417: Is the process in which a mineral dissolves completely without producing any new solid substance. Rainwater easily dissolves soluble minerals, such as halite or gypsum , but can also dissolve highly resistant minerals such as quartz , given sufficient time. Water breaks the bonds between atoms in the crystal: [REDACTED] The overall reaction for dissolution of quartz is The dissolved quartz takes

3960-431: Is usually much less important than chemical weathering, but can be significant in subarctic or alpine environments. Furthermore, chemical and physical weathering often go hand in hand. For example, cracks extended by physical weathering will increase the surface area exposed to chemical action, thus amplifying the rate of disintegration. Frost weathering is the most important form of physical weathering. Next in importance

4070-426: Is wedging by plant roots, which sometimes enter cracks in rocks and pry them apart. The burrowing of worms or other animals may also help disintegrate rock, as can "plucking" by lichens. Frost weathering is the collective name for those forms of physical weathering that are caused by the formation of ice within rock outcrops. It was long believed that the most important of these is frost wedging , which results from

4180-638: The Blue Ridge Mountains in eight Virginia counties. Although the Skyline Drive right-of-way was purchased from owners without condemnation, the costs of the acreage purchased trebled over initial estimates and the acreage decreased to what Carson called a "fish-bone" shape and others a "shoestring". Although Byrd and Carson convinced Congress to reduce the minimum size of Shenandoah Park to just over 160,000 acres (250.0 sq mi; 647.5 km) to eliminate some high-priced lands, in 1933 newly elected President Franklin D. Roosevelt decided to also create

4290-613: The Blue Ridge Parkway that Byrd wanted. President Franklin Delano Roosevelt formally opened Shenandoah National Park on July 3, 1936. Eventually, about 40 people (on the "Ickes list") were allowed to live out their lives on land that became the park. One of them was George Freeman Pollock, whose residence Killahevlin was later listed on the National Register, and whose Skyland Resort reopened under

4400-488: The Blue Ridge Parkway to connect to then-under-construction Skyline Drive on the Shenandoah National Park ridgeline, which required additional condemnations. When many families continued to refuse to sell their land in 1932 and 1933, proponents changed tactics. Freeman hired social worker Miriam Sizer to teach at a summer school he had set up near one of his workers' communities and asked her to write

4510-421: The campgrounds are open from April to October–November. There are five major campgrounds: There are several lodges/cabins in the park: Lodges are located at Skyland and Big Meadows . The park's Harry F. Byrd Visitor Center is also located at Big Meadows. Another visitor center is located at Dickey Ridge. Campgrounds are located at Mathews Arm, Big Meadows, Lewis Mountain, and Loft Mountain. Rapidan Camp ,

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4620-602: The territories of American Samoa and the U.S. Virgin Islands . The state with the most national parks is California with nine, followed by Alaska with eight, Utah with five, and Colorado with four. The largest national park is Wrangell–St. Elias in Alaska: at over 8 million acres (32,375 km ), it is larger than each of the nine smallest states . The next three largest parks are also in Alaska. The smallest park

4730-548: The 1940s and made them available to overnight hikers. Some displaced residents (and their descendants) created the Children of the Shenandoah to lobby for more balanced presentations. In the 1990s, the park hired cultural resource specialists and conducted an archeological inventory of existing structures, the Survey of Rural Mountain Settlement. Eventually, the park's new focus on cultural resources coincided with agitation from

4840-479: The 500 miles of trails of the Shenandoah National Park. Streams and rivers in the park are very popular with fly fisherman for native brook trout . Many waterfalls are located within the park boundaries. Below is a list of significant falls. Beginning at mile 50.7 of the Skyline Drive near the Byrd Visitor Center, Dark Hollow Falls Trail leads downhill beside Hogcamp Branch to Dark Hollow Falls,

4950-408: The Earth's surface, begins weathering with the destruction of hornblende . Biotite then weathers to vermiculite , and finally oligoclase and microcline are destroyed. All are converted into a mixture of clay minerals and iron oxides. The resulting soil is depleted in calcium, sodium, and ferrous iron compared with the bedrock, and magnesium is reduced by 40% and silicon by 15%. At the same time,

5060-411: The Earth's surface. Chemical weathering takes place when water, oxygen, carbon dioxide, and other chemical substances react with rock to change its composition. These reactions convert some of the original primary minerals in the rock to secondary minerals, remove other substances as solutes, and leave the most stable minerals as a chemically unchanged resistate . In effect, chemical weathering changes

5170-601: The Government. I signed everythin' they asked me." In the early 1930s, the National Park Service began planning the park facilities and envisioned separate provisions for blacks and whites. At that time, in Jim Crow Virginia, racial segregation was the order of the day. In its transfer of the parkland to the federal government, Virginia initially attempted to ban African Americans entirely from

5280-595: The Interior Department was increasingly anxious to eliminate segregation from all parks. Pinnacles picnic ground was selected to be the initial integrated site in the Shenandoah, but Virginia Sky-Line Company continued to balk, and distributed maps showing Lewis Mountain as the only site for African Americans. During World War II, concessions closed, and park usage plunged. But once the War ended, in December 1945,

5390-991: The Looking Glass Art Gallery in the historic Hawley Silk Mill , in Hawley, Pennsylvania . List of national parks of the United States The United States has 63 national parks , which are congressionally designated protected areas operated by the National Park Service , an agency of the Department of the Interior . National parks are designated for their natural beauty, unique geological features, diverse ecosystems, and recreational opportunities, typically "because of some outstanding scenic feature or natural phenomena." While legislatively all units of

5500-448: The NPS mandated that all concessions in all national parks were to be desegregated. In October 1947 the dining rooms of Lewis Mountain and Panorama were integrated and by early 1950, the mandate was fully accomplished. Particularly after the 1960s, park operations broadened from nature-focused to include social history. The Potomac Appalachian Trail Club had restored some cabins beginning in

5610-535: The National Park Service "to conserve the scenery and the natural and historic objects and wildlife therein, and to provide for the enjoyment of the same in such manner and by such means as will leave them unimpaired for the enjoyment of future generations." Many current national parks had been previously protected as national monuments by the president under the Antiquities Act or as other designations created by Congress before being redesignated by Congress;

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5720-665: The National Park System are considered equal with the same mission, national parks are generally larger and more of a destination, and hunting and extractive activities are prohibited. National monuments , on the other hand, are also frequently protected for their historical or archaeological significance. Eight national parks (including six in Alaska ) are paired with a national preserve , areas with different levels of protection that are administered together but considered separate units and whose areas are not included in

5830-409: The affected rocks a reddish-brown coloration on the surface which crumbles easily and weakens the rock. Many other metallic ores and minerals oxidize and hydrate to produce colored deposits, as does sulfur during the weathering of sulfide minerals such as chalcopyrites or CuFeS 2 oxidizing to copper hydroxide and iron oxides . Mineral hydration is a form of chemical weathering that involves

5940-466: The atmosphere and can affect climate. Aluminosilicates containing highly soluble cations, such as sodium or potassium ions, will release the cations as dissolved bicarbonates during acid hydrolysis: Within the weathering environment, chemical oxidation of a variety of metals occurs. The most commonly observed is the oxidation of Fe ( iron ) by oxygen and water to form Fe oxides and hydroxides such as goethite , limonite , and hematite . This gives

6050-493: The backcountry, campers must use a " Leave No Trace " policy that includes burying excrement and not building campfires. Backcountry campers must also be careful of wildlife such as bears and venomous snakes. Campers must suspend their food from trees while not in use in "bear bags" or park-approved bear canisters to prevent unintentionally feeding the bears, who then become habituated to humans and their food and therefore dangerous. All animals are protected by federal law. Most of

6160-539: The bedrock throughout the park. The park is located along the western part of the Blue Ridge anticlinorium , a regional-scale Paleozoic structure at the eastern margin of the Appalachian fold and thrust belt . Rocks within the park were folded , faulted , distorted, and metamorphosed during the late Paleozoic Alleghanian orogeny (325 to 260 million years ago). The rugged topography of Blue Ridge Mountains

6270-463: The breakdown of rocks and soils through such mechanical effects as heat, water, ice and wind. The latter covers reactions to water, atmospheric gases and biologically produced chemicals with rocks and soils. Water is the principal agent behind both kinds, though atmospheric oxygen and carbon dioxide and the activities of biological organisms are also important. Biological chemical weathering is also called biological weathering. The materials left after

6380-819: The carbon dioxide level to 30% of all soil gases, aided by adsorption of CO 2 on clay minerals and the very slow diffusion rate of CO 2 out of the soil. The CO 2 and organic acids help break down aluminium - and iron -containing compounds in the soils beneath them. Roots have a negative electrical charge balanced by protons in the soil next to the roots, and these can be exchanged for essential nutrient cations such as potassium. Decaying remains of dead plants in soil may form organic acids which, when dissolved in water, cause chemical weathering. Chelating compounds, mostly low molecular weight organic acids, are capable of removing metal ions from bare rock surfaces, with aluminium and silicon being particularly susceptible. The ability to break down bare rock allows lichens to be among

6490-530: The early 20th century that seemed to show that its effects were unimportant. These experiments have since been criticized as unrealistic, since the rock samples were small, were polished (which reduces nucleation of fractures), and were not buttressed. These small samples were thus able to expand freely in all directions when heated in experimental ovens, which failed to produce the kinds of stress likely in natural settings. The experiments were also more sensitive to thermal shock than thermal fatigue, but thermal fatigue

6600-429: The existing facilities and add new lodges, cabins, and other amenities, including Big Meadows Lodge . Under their plan, all the sites in the parks, save one, were for "whites only". Their plan included a separate facility for African Americans at Lewis Mountain—a picnic ground, a smaller lodge, cabins and a campground. The site opened in 1939, and it was substantially inferior to the other park facilities. By then, however,

6710-427: The expansion of pore water when it freezes. A growing body of theoretical and experimental work suggests that ice segregation, whereby supercooled water migrates to lenses of ice forming within the rock, is the more important mechanism. When water freezes, its volume increases by 9.2%. This expansion can theoretically generate pressures greater than 200 megapascals (29,000 psi), though a more realistic upper limit

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6820-404: The expense of silica, titanium, aluminum, ferrous iron, and calcium. Buildings made of any stone, brick or concrete are susceptible to the same weathering agents as any exposed rock surface. Also statues , monuments and ornamental stonework can be badly damaged by natural weathering processes. This is accelerated in areas severely affected by acid rain . Accelerated building weathering may be

6930-540: The field. In 2014, under the leadership of Superintendent Jim Northup, Shenandoah National Park established an Artist-in-Residence Program that is administered by the Shenandoah National Park Trust, the park's philanthropic partner. Photographer Sandy Long was selected as the park's first artist-in-residence. The results of Long's residency were featured in the photography exhibit "Wild Beauty: The Artful Nature of Shenandoah National Park" held at

7040-552: The figures below. The 431 units of the National Park System can be broadly referred to as national parks, but most have other formal designations. A bill creating the first national park, Yellowstone , was signed into law by President Ulysses S. Grant in 1872, followed by Mackinac National Park in 1875 (decommissioned in 1895), and then Rock Creek Park (later merged into National Capital Parks ), Sequoia and Yosemite in 1890. The Organic Act of 1916 created

7150-488: The first colonizers of dry land. The accumulation of chelating compounds can easily affect surrounding rocks and soils, and may lead to podsolisation of soils. The symbiotic mycorrhizal fungi associated with tree root systems can release inorganic nutrients from minerals such as apatite or biotite and transfer these nutrients to the trees, thus contributing to tree nutrition. It was also recently evidenced that bacterial communities can impact mineral stability leading to

7260-463: The form of silicic acid . A particularly important form of dissolution is carbonate dissolution, in which atmospheric carbon dioxide enhances solution weathering. Carbonate dissolution affects rocks containing calcium carbonate , such as limestone and chalk . It takes place when rainwater combines with carbon dioxide to form carbonic acid , a weak acid , which dissolves calcium carbonate (limestone) and forms soluble calcium bicarbonate . Despite

7370-669: The geologic record. Indications that a sedimentary bed is a paleosol include a gradational lower boundary and sharp upper boundary, the presence of much clay, poor sorting with few sedimentary structures, rip-up clasts in overlying beds, and desiccation cracks containing material from higher beds. The degree of weathering of soil can be expressed as the chemical index of alteration , defined as 100 Al 2 O 3 /(Al 2 O 3 + CaO + Na 2 O + K 2 O) . This varies from 47 for unweathered upper crust rock to 100 for fully weathered material. Wood can be physically and chemically weathered by hydrolysis and other processes relevant to minerals and

7480-439: The ice will simply expand into the air spaces in the unsaturated rock without generating much pressure. These conditions are unusual enough that frost wedging is unlikely to be the dominant process of frost weathering. Frost wedging is most effective where there are daily cycles of melting and freezing of water-saturated rock, so it is unlikely to be significant in the tropics, in polar regions or in arid climates. Ice segregation

7590-573: The land to create Shenandoah National Park. Virginia's Democratic gubernatorial candidate (and the late Congressman Flood's nephew), Harry F. Byrd supported the creation of Shenandoah National Park, as did his friend William E. Carson , a businessman who had become Virginia's first chairman of the Commission on Conservation and Development. Development of the western national parks had assisted tourism, which produced jobs, which Byrd and local politicians supported. The land that became Shenandoah park

7700-757: The main park road, generally traversing along the ridgeline of the mountains. Almost 40% of the park's land—79,579 acres (124 sq mi; 322 km)—has been designated as wilderness areas and is protected as part of the National Wilderness Preservation System . The highest peak is Hawksbill Mountain at 4,051 feet (1,235 m). As stated in the foundation document: Shenandoah National Park preserves and protects nationally significant natural and cultural resources, scenic beauty, and congressionally designated wilderness within Virginia’s northern Blue Ridge Mountains, and provides

7810-546: The most effective biological agents of chemical weathering. For example, an experimental study on hornblende granite in New Jersey, US, demonstrated a 3x – 4x increase in weathering rate under lichen covered surfaces compared to recently exposed bare rock surfaces. The most common forms of biological weathering result from the release of chelating compounds (such as certain organic acids and siderophores ) and of carbon dioxide and organic acids by plants. Roots can build up

7920-661: The most-visited park since 1944, and had almost 13 million visitors in 2022. In contrast, only about 9,500 people visited the remote Gates of the Arctic National Park and Preserve in Alaska in 2022. Download coordinates as: The following table includes the 30 states and two territories that have national parks. Exclusive parks refer to parks entirely within one state or territory. Shared parks refer to parks in multiple states. Territories are set in italics . Differential erosion Weathering processes are either physical or chemical. The former involves

8030-513: The moths would primarily consume the leaves of oak trees. Though the gypsy moths seem to have abated, they continue to affect the forest and have destroyed almost ten percent of the oak groves. Mammals include black bear , coyote , striped skunk , spotted skunk , raccoon , beaver , river otter , opossum , woodchuck , bobcat , two species of foxes , white-tailed deer , and eastern cottontail rabbit . Though unsubstantiated, there have been some reported sightings of cougar in remote areas of

8140-431: The national park selection committee. However, many local families who had lived in the area for generations (especially people over 60 years old) did not want to sell their land, and some refused to sell at any price. Carson promised that if they sold to the commonwealth, they could still live on their homesteads for the rest of their lives. Carson also lobbied the new president, Herbert Hoover , who bought land to establish

8250-708: The new Skyline Drive not be evicted. When evictions kept creating negative publicity in 1935, photographer Arthur Rothstein coordinated with the Hollow Folk authors and then went to document the conditions they claimed. The creation of the park had immediate benefits to some Virginians. During the Great Depression , many young men received training and jobs through the Civilian Conservation Corps (CCC). The first CCC camp in Virginia

8360-472: The newest national park is New River Gorge , previously a National River, and the most recent entirely new park is National Park of American Samoa . A few former national parks are no longer designated as such , or have been disbanded. Fourteen national parks are designated UNESCO World Heritage Sites (WHS), and 21 national parks are named UNESCO Biosphere Reserves (BR), with eight national parks in both programs. Thirty states have national parks, as do

8470-551: The original set of minerals in the rock into a new set of minerals that is in closer equilibrium with surface conditions. True equilibrium is rarely reached, because weathering is a slow process, and leaching carries away solutes produced by weathering reactions before they can accumulate to equilibrium levels. This is particularly true in tropical environments. Water is the principal agent of chemical weathering, converting many primary minerals to clay minerals or hydrated oxides via reactions collectively described as hydrolysis . Oxygen

8580-558: The other hand, CCC crews were assigned to burn and destroy some cabins in the park, to prevent residents from coming back. Also, U.S. Secretary of the Interior Harold Ickes who had jurisdiction over the NPS and partial jurisdiction over the CCC, tried to use his authority to force Byrd to cooperate on other New Deal projects. Shenandoah National Park was finally established on December 26, 1935, and soon construction began on

8690-506: The other reports exaggerated, as did Episcopal missionary teachers in other Blue Ridge areas). Carson had had ambitions to become governor in 1929 and 1933, but Byrd instead selected George C. Peery of Virginia's southwestern region to succeed easterner Pollard. After winning the election, Peery and Carson's successor would establish Virginia's state park system, although plans to relocate reluctant residents kept changing and basically failed. Carson had hoped to head that new state agency but

8800-443: The overlying rock material. When erosion removes the overlying rock material, these intrusive rocks are exposed and the pressure on them is released. The outer parts of the rocks then tend to expand. The expansion sets up stresses which cause fractures parallel to the rock surface to form. Over time, sheets of rock break away from the exposed rocks along the fractures, a process known as exfoliation . Exfoliation due to pressure release

8910-506: The park but settled for enforcing its segregation laws in the park's facilities. By the 1930s, there were several concessions operated by private firms within the area that would become the park, some going back to the late 19th century. These early private facilities at Skyland Resort, Panorama Resort , and Swift Run Gap were operated only for whites. By 1937, the Park Service accepted a bid from Virginia Sky-Line Company to take over

9020-472: The park, including brook trout , longnose and eastern blacknose dace , and the bluehead chub . Park rangers organize several programs from spring to fall. These include ranger-led hikes, as well as discussions of the history, flora, and fauna. Shenandoah Live is an online series where listeners may chat live with rangers and learn about some of the park's features. Rangers discuss a wide range of topics while answering questions and talking with experts from

9130-598: The park. In total, there are over 500 miles (800 km) of trails within the park. There is also horseback riding, camping, bicycling , and a number of waterfalls . The Skyline Drive is the first National Park Service road east of the Mississippi River listed as a National Historic Landmark on the National Register of Historic Places. It is also designated as a National Scenic Byway . Shenandoah National Park offers 196,000 acres (306.2 sq mi; 793.2 km) of backcountry and wilderness camping. While in

9240-428: The park. Over 200 species of birds make their home in the park for at least part of the year. About thirty live in the park year-round, including the barred owl , Carolina chickadee , red-tailed hawk , and wild turkey . The peregrine falcon was reintroduced into the park in the mid-1990s and by the end of the 20th century there were numerous nesting pairs in the park. Thirty-two species of fish have been documented in

9350-565: The payments because they needed the money and wanted to escape the subsistence lifestyle. Nearly 90 percent of the inhabitants worked the land for a living: selling timber, charcoal, or crops. They had previously been able to earn money to buy supplies by harvesting the now-rare chestnuts, by working during the apple and peach harvest season (but the drought of 1930 devastated those crops and killed many fruit trees), or by selling handmade textiles and crafts (displaced by factories) and moonshine (illegal after Prohibition started). However, Carson and

9460-440: The permit process arbitrary. Businessman Robert H. Via filed suit against the condemnations in 1934 but did not prevail (and ended up moving to Pennsylvania and never cashed his condemnation check). Carson announced his resignation from his unpaid job effective in December 1934. As one of his final acts, Carson wrote the new NPS director, Arno B. Cammerer , urging that 60 people over 60 years of age whose plots were not visible from

9570-526: The politicians did not seek citizen input early in the process, nor convince residents that they could live better in a tourist economy. Instead, they started with an advertising campaign to raise the funds, and courthouse property evaluations and surveys. Upon Mather's death in 1929, the new NPS director, Horace M. Albright also decided that the federal agency would only accept vacant land, so even elderly residents would be forced to leave. Thus, many families and entire communities were forced to vacate portions of

9680-402: The production of weathering agents, such as protons, organic acids and chelating molecules. Weathering of basaltic oceanic crust differs in important respects from weathering in the atmosphere. Weathering is relatively slow, with basalt becoming less dense, at a rate of about 15% per 100 million years. The basalt becomes hydrated, and is enriched in total and ferric iron, magnesium, and sodium at

9790-597: The range divides the Shenandoah River drainage basin , part of the Potomac River drainage, on the west side, from the James and Rappahannock River drainage basins on the east side. Some of the rocks exposed in the park date to over one billion years in age, making them among the oldest in Virginia. Bedrock in the park includes Grenville-age granitic basement rocks (1.2–1.0 billion years old) and

9900-416: The release of inorganic nutrients. A large range of bacterial strains or communities from diverse genera have been reported to be able to colonize mineral surfaces or to weather minerals, and for some of them a plant growth promoting effect has been demonstrated. The demonstrated or hypothesised mechanisms used by bacteria to weather minerals include several oxidoreduction and dissolution reactions as well as

10010-538: The restored presidential fishing retreat Herbert Hoover built on the Rapidan River in 1929, is accessed by a 4.1-mile (6.6 km) round-trip hike on Mill Prong Trail, which begins on the Skyline Drive at Milam Gap (Mile 52.8). The NPS also offers guided van trips that leave from the Byrd Center at Big Meadows. Shenandoah National Park is one of the most dog-friendly in the national park system. The campgrounds all allow dogs, and dogs are allowed on almost all of

10120-448: The rigid attachment of water molecules or H+ and OH- ions to the atoms and molecules of a mineral. No significant dissolution takes place. For example, iron oxides are converted to iron hydroxides and the hydration of anhydrite forms gypsum . Bulk hydration of minerals is secondary in importance to dissolution, hydrolysis, and oxidation, but hydration of the crystal surface is the crucial first step in hydrolysis. A fresh surface of

10230-472: The rock breaks down combine with organic material to create soil . Many of Earth's landforms and landscapes are the result of weathering, erosion and redeposition. Weathering is a crucial part of the rock cycle ; sedimentary rock , the product of weathered rock, covers 66% of the Earth's continents and much of the ocean floor . Physical weathering , also called mechanical weathering or disaggregation ,

10340-455: The rock surface, which gradually pry the rock apart. Thermal stress weathering results from the expansion and contraction of rock due to temperature changes. Thermal stress weathering is most effective when the heated portion of the rock is buttressed by surrounding rock, so that it is free to expand in only one direction. Thermal stress weathering comprises two main types, thermal shock and thermal fatigue . Thermal shock takes place when

10450-413: The rock. This results in growth of the ice grain that puts considerable pressure on the surrounding rock, up to ten times greater than is likely with frost wedging. This mechanism is most effective in rock whose temperature averages just below the freezing point, −4 to −15 °C (25 to 5 °F). Ice segregation results in growth of ice needles and ice lenses within fractures in the rock and parallel to

10560-408: The rocks and evaporate, leaving salt crystals behind. As with ice segregation, the surfaces of the salt grains draw in additional dissolved salts through capillary action, causing the growth of salt lenses that exert high pressure on the surrounding rock. Sodium and magnesium salts are the most effective at producing salt weathering. Salt weathering can also take place when pyrite in sedimentary rock

10670-425: The rocks on which it falls. Hydrolysis (also called incongruent dissolution ) is a form of chemical weathering in which only part of a mineral is taken into solution. The rest of the mineral is transformed into a new solid material, such as a clay mineral . For example, forsterite (magnesium olivine ) is hydrolyzed into solid brucite and dissolved silicic acid: Most hydrolysis during weathering of minerals

10780-536: The soil is enriched in aluminium and potassium by at least 50%; by titanium, whose abundance triples, and ferric iron, whose abundance increases by an order of magnitude compared with the bedrock. Basaltic rock is more easily weathered than granitic rock due to its formation at higher temperatures and drier conditions. The fine grain size and presence of volcanic glass also hasten weathering. In tropical settings, it rapidly weathers to clay minerals, aluminium hydroxides, and titanium-enriched iron oxides. Because most basalt

10890-482: The southern end where residents could see tourism's benefits at Thomas Jefferson's Monticello since the 1920s, as well as the jobs available in the Shenandoah and new Blue Ridge projects. In 1931 and 1932, residents were allowed to petition the state agency to stay another year to gather crops, etc. However, some refused to cooperate to any extent, others wanted to continue to use resources now protected (including timber or homes and gardens vacated by others), and many found

11000-419: The stresses are so great that the rock cracks immediately, but this is uncommon. More typical is thermal fatigue, in which the stresses are not great enough to cause immediate rock failure, but repeated cycles of stress and release gradually weaken the rock. Thermal stress weathering is an important mechanism in deserts , where there is a large diurnal temperature range, hot in the day and cold at night. As

11110-454: The surface of the crystal, and that the weathering layer is only a few atoms thick. Diffusion within the mineral grain does not appear to be significant. Mineral weathering can also be initiated or accelerated by soil microorganisms. Soil organisms make up about 10 mg/cm of typical soils, and laboratory experiments have demonstrated that albite and muscovite weather twice as fast in live versus sterile soil. Lichens on rocks are among

11220-591: The town of Front Royal in the northeast to near the city of Waynesboro in the southwest. The park headquarters are located in Luray . Shenandoah National Park lies along the Blue Ridge Mountains in north-central Virginia. These mountains form a distinct highland rising to elevations above 4,000 feet (1,200 m). Local topographic relief between the Blue Ridge Mountains and Shenandoah Valley exceeds 3,000 feet (900 m) at some locations. The crest of

11330-592: The trails including the Appalachian Trail, if kept on leash (6 feet or shorter). Dogs are not allowed on ten trails: Fox Hollow Trail, Stony Man Trail, Limberlost Trail, Post Office Junction to Old Rag Shelter, Old Rag Ridge Trail, Old Rag Saddle Trail, Dark Hollow Falls Trail, Story of the Forest Trail, Bearfence Mountain Trail, Frazier Discovery Trail. These ten trails fall short of a total of 20 miles of

11440-485: The western mold, becoming the first eastern national park. It was also based on donations from wealthy private landowners. Stephen Mather , the first NPS director, saw a need for a national park in the southern states, and solicited proposals in his 1923 year-end report. In May 1926, Congress and President Calvin Coolidge authorized the NPS to acquire a minimum of 250,000 acres (390.6 sq mi; 1,011.7 km) and

11550-537: Was Byrd's law partner) tried to figure out who owned the land. They found that it consisted of more than 5,000 parcels, some of them inhabited by tenant farmers or squatters (who were ineligible to receive compensation). Some landowners, including wealthy resort owner George Freeman Pollock and Luray Realtor and developer L. Ferdinand Zerkel, had long wanted the park created and had formed the Northern Virginia Park Association to win over

11660-404: Was effectively brought to extinction by a fungus known as the chestnut blight during the 1930s; though the tree continues to grow in the park, it does not reach maturity and dies back before it can reproduce. Various species of oaks superseded the chestnuts and became the dominant tree species. Gypsy moth infestations beginning in the early 1990s began to erode the dominance of the oak forests as

11770-550: Was established in the George Washington National Forest near Luray , and Governor Pollard quickly filled his initial quota of 5,000 workers. About 1,000 men and boys worked on Skyline Drive, and about 100,000 worked in Virginia during the agency's existence. In Shenandoah Park, CCC crews removed many of the dead chestnut trees whose skeletons marred views in the new park, as well as constructed trails and facilities. Tourism revenues also skyrocketed. On

11880-427: Was not selected because of his growing differences with Byrd, over fees owed his brother and especially over the evictions that began in late 1933 against his advice but pursuant to new federal policies and that garnered much negative publicity. Most of the reluctant families came from the park's central counties ( Madison , Page , and Rappahannock ), not the northern counties nearest Byrd's and Carson's bases, or from

11990-501: Was scenic, mountainous, and had also lost about half of its trees to the Chestnut blight (which was incurable and affected trees as they reached maturity). However, it had been held as private property for over a century, so many farms and orchards existed. After Byrd became governor and convinced the legislature to appropriate $ 1 million for land acquisition and other work, Carson and his teams (including surveyors and his brother Kit who

12100-433: Was signed into law in 1872. Yosemite National Park was created in 1890. When Congress created the National Park Service (NPS) in 1916, additional parks had maintained the western pattern ( Crater Lake in 1902, Wind Cave in 1903, Mesa Verde in 1906, then Denali in 1917). Grand Canyon , Zion and Acadia were all created in 1919 during the administration of Virginia-born president Woodrow Wilson . Acadia finally broke

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