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34-644: Glen Rock or Glenrock may refer to: Geology [ edit ] Glen Rock (boulder) in Glen Rock, New Jersey Places [ edit ] Australia [ edit ] Glenrock, Queensland , a locality in the South Burnett Region, Queensland United States [ edit ] Glenrock, Nebraska , an unincorporated community in Nemaha County Glen Rock, New Jersey ,

68-835: A borough in Bergen County Glen Rock, Pennsylvania , a borough in York County Glen Rock, Virginia , a neighborhood in Norfolk County Glenrock, Wyoming , a town in Converse County Railway stations [ edit ] Glen Rock–Main Line station , on New Jersey Transit's Main Line Glen Rock–Boro Hall station , on New Jersey Transit's Bergen County Line [REDACTED] Topics referred to by

102-572: A broad textural category for medium- to coarse-grained metamorphic rock that shows poorly developed schistosity, with compositional layering over 5 millimeters (0.20 in) thick and tending to split into plates over 1 centimeter (0.39 in) thick. Neither definition depends on composition or origin, though rocks poor in platy minerals are more likely to produce gneissose texture. Gneissose rocks thus are largely recrystallized but do not carry large quantities of micas, chlorite or other platy minerals. Metamorphic rock showing stronger schistosity

136-515: A committee to raise funds to place a memorial plaque on the Glen Rock to honor the town's veterans of the United States military who had died during World War I . The council had initially attempted to allocate $ 500 towards the project that February, but turned to fundraising efforts in March after they discovered that there were no contingency funds available to spend. The committee, with

170-571: A landmark used in the division of land in West Jersey as early as 1687. The rock served as a key marker for all colonial-era land deeds, composing one of the points used in the eighteenth-century survey of the Ramapo Tract . In 1894, a group of Ridgewood, New Jersey residents seceded from the then-township to form a new municipality, calling it the "Borough of Glen Rock" after the glacial erratic within its newly formed borders. The rock

204-475: Is a gneiss resulting from metamorphism of granite, which contains characteristic elliptic or lenticular shear-bound grains ( porphyroclasts ), normally feldspar , surrounded by finer grained material. The finer grained material deforms around the more resistant feldspar grains to produce this texture. Migmatite is a gneiss consisting of two or more distinct rock types, one of which has the appearance of an ordinary gneiss (the mesosome ), and another of which has

238-488: Is a metamorphic rock composed of mineral grains easily seen with the unaided eye, which form obvious compositional layers, but which has only a weak tendency to fracture along these layers. In Europe, the term has been more widely applied to any coarse, mica -poor, high-grade metamorphic rock. The British Geological Survey (BGS) and the International Union of Geological Sciences (IUGS) both use gneiss as

272-518: Is called gneissic banding. The darker bands have relatively more mafic minerals (those containing more magnesium and iron ). The lighter bands contain relatively more felsic minerals (minerals such as feldspar or quartz , which contain more of the lighter elements, such as aluminium , sodium , and potassium ). The banding is developed at high temperature when the rock is more strongly compressed in one direction than in other directions ( nonhydrostatic stress ). The bands develop perpendicular to

306-449: Is classified as schist, while metamorphic rock devoid of schistosity is called a granofels . Gneisses that are metamorphosed igneous rocks or their equivalent are termed granite gneisses, diorite gneisses, and so forth. Gneiss rocks may also be named after a characteristic component such as garnet gneiss, biotite gneiss, albite gneiss, and so forth. Orthogneiss designates a gneiss derived from an igneous rock , and paragneiss

340-463: Is different from Wikidata All article disambiguation pages All disambiguation pages Glen Rock (boulder) The Glen Rock is a 570-ton boulder located in Glen Rock , New Jersey , United States. The boulder, which is the namesake of the town in which it is located, is the largest glacial erratic found atop Triassic bedrock in the state of New Jersey . The exact origin of

374-539: Is located across from the home of Peter Ebbert, the first resident of the borough to have been killed-in-action during the conflict. Over time, the Glen Rock became a symbol of the Borough of Glen Rock. In 1964, the New Jersey State Office of Historic Sites designated the Glen Rock as a historical landmark and placed a commemorative sign beside the war memorial. In 1969, on the 75th anniversary of

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408-517: Is one from a sedimentary rock . Both the BGS and the IUGS use gneissose to describe rocks with the texture of gneiss, though gneissic also remains in common use. For example, a gneissose metagranite or a gneissic metagranite both mean a granite that has been metamorphosed and thereby acquired gneissose texture. The minerals in gneiss are arranged into layers that appear as bands in cross section. This

442-510: Is subjected to extreme temperature and pressure and is composed of alternating layers of sandstone (lighter) and shale (darker), which is metamorphosed into bands of quartzite and mica. Another cause of banding is "metamorphic differentiation", which separates different materials into different layers through chemical reactions, a process not fully understood. Augen gneiss , from the German : Augen [ˈaʊɡən] , meaning "eyes",

476-646: Is the largest glacial erratic found atop Triassic bedrock in the state of New Jersey. The boulder, a large glacial erratic, is not native to the Newark Basin . Its exact location of origin is uncertain. A 1971 report by the New Jersey Geological Survey found that the rock was carried between ten and twenty miles from the New Jersey Highlands to its current location in Glen Rock, New Jersey as glaciers receded during

510-488: The First World War , a memorial plaque was installed on the rock to honor veterans who had died during the conflict. In 1964, the New Jersey State Office of Historic Sites designated the Glen Rock as a state landmark. The Glen Rock is composed of gneiss , though the rock has granitic aspects. The Glen Rock measures forty-four feet wide, twenty-two feet high, and twelve feet long. The boulder weights 570 tons and

544-655: The end of the last Ice Age , while a 2009 report by the Borough of Glen Rock finds that the most likely origin of the rock are the southeastern areas of the Hudson Highlands located in New York State , citing the boulder's rounded shape and the Hudson Highlands' bedrock composition. The boulder is located in the center of a former glacial lake; the boulder may have floated upon an iceberg and subsequently sank into its current location. Prior to

578-527: The Borough of Glen Rock's founding, a time capsule to be opened in 2044 was buried in the ground beside the Glen Rock. By the mid-1970s, the sign provided by the Office of Historic Sites had disappeared, having been stolen from its location next to the glacial erratic. A replica of the original sign, which contained information on the boulder's history, was created and screwed onto a seven-foot-tall pole constructed to deter vandals in 1985. The replacement sign

612-458: The amphibolite or granulite facies. These form most of the exposed rock in Archean cratons . Gneiss domes are common in orogenic belts (regions of mountain formation). They consist of a dome of gneiss intruded by younger granite and migmatite and mantled with sedimentary rock. These have been interpreted as a geologic record of two distinct mountain-forming events, with the first producing

646-538: The appearance of an intrusive rock such pegmatite , aplite , or granite the ( leucosome ). The rock may also contain a melanosome of mafic rock complementary to the leucosome. Migmatites are often interpreted as rock that has been partially melted, with the leucosome representing the silica-rich melt, the melanosome the residual solid rock left after partial melting, and the mesosome the original rock that has not yet experienced partial melting. Gneisses are characteristic of areas of regional metamorphism that reaches

680-405: The arrival of European settlers, Native Americans used the Glen Rock as a trail marker as well as a place to build signal fires. The Lenape , who were natives of the region, referred to the boulder as Pamackapuka (also transliterated Pammackapuka ). The meaning of the name is disputed; some translate the name of the rock as "stone from heaven" or "stone from the sky", while others translate

714-416: The bottom of the deck in the other direction. These forces stretch out the rock like a plastic , and the original material is spread out into sheets. Per the polar decomposition theorem , the deformation produced by such shearing force is equivalent to rotation of the rock combined with shortening in one direction and extension in another. Some banding is formed from original rock material (protolith) that

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748-421: The boulder. The soil removal revealed the boulder's massive size. In 1912, the Glen Rock was threatened with destruction due to the ongoing roadwork in the borough. Developers initially desired to destroy the boulder, though they faced public outcry from borough residents who felt that the rock had substantial historical value. Later, they decided to construct the road to go around the landmark rock and to transfer

782-497: The deed for the land on which the rock resides to the borough. In October of that year, work was undertaken to support the base of the Glen Rock with additional stonework and wide cement walkway was added to improve the quality of the area. The Paterson Morning Call described the rock as having "considerable historic value" and commented approvingly on the renovations. In 1921, the Borough Council of Glen Rock created

816-402: The direction of greatest compression, also called the shortening direction, as platy minerals are rotated or recrystallized into parallel layers. A common cause of nonhydrodynamic stress is the subjection of the protolith (the original rock material that undergoes metamorphism) to extreme shearing force, a sliding force similar to the pushing of the top of a deck of cards in one direction, and

850-595: The granite basement and the second deforming and melting this basement to produce the domes. However, some gneiss domes may actually be the cores of metamorphic core complexes , regions of the deep crust brought to the surface and exposed during extension of the Earth's crust . The word gneiss has been used in English since at least 1757. It is borrowed from the German word Gneis , formerly also spelled Gneiss , which

884-487: The help of the local Boy Scouts , successfully raised enough funds for the project to be completed; the bronze plaque was subsequently installed and was unveiled at a ceremony held on May 30 of that year. The plaque fixed on the rock bears the names of five individuals from the borough who died during the First World War, as well as the names of eighty-nine others who honorably served in combat. The Glen Rock

918-521: The middle amphibolite to granulite metamorphic facies . In other words, the rock was metamorphosed at a temperature in excess of 600 °C (1,112 °F) at pressures between about 2 to 24 kbar . Many different varieties of rock can be metamorphosed to gneiss, so geologists are careful to add descriptions of the color and mineral composition to the name of any gneiss, such as garnet-biotite paragneiss or grayish-pink orthogneiss . Continental shields are regions of exposed ancient rock that make up

952-426: The name of the rock as " sweat house ". The large rock was also used by indigenous chieftains as a throne when presiding over meetings with members of their tribe and served as the location of several inter-tribal meetings among natives. Later, as colonists arrived to the region, they used the rock as a landmark for their trails. The rock, referred to as "Big Rock at Small Lots" by early colonists, began serving as

986-464: The rock as a trail marker, a location to build signal fires, and as a throne for chiefs used when presiding over meetings. Later, beginning in colonial times, European settlers to the region used the rock as a landmark on trails and as a marker for land deeds. The Glen Rock, which had been largely submerged under soil, was excavated during road work in 1912; supporting structures were added to the rock during that time to prevent it from collapsing. Following

1020-466: The rock is uncertain, though studies alternatively place its origin in New York State's Hudson Highlands and the New Jersey Highlands . The Glen Rock, which is composed of gneiss , is located in the center of a former glacial lake. The cultural history of the Glen Rock predates the settlement of New Jersey by European colonists. The Lenape , who referred to the boulder as Pamackapuka , used

1054-427: The same term This disambiguation page lists articles about distinct geographical locations with the same name. If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=Glen_Rock&oldid=1062904069 " Category : Place name disambiguation pages Hidden categories: Short description

Glen Rock - Misplaced Pages Continue

1088-596: The stable cores of continents. The rock exposed in the oldest regions of shields, which is of Archean age (over 2500 million years old), mostly belong to granite-greenstone belts. The greenstone belts contain metavolcanic and metasedimentary rock that has undergone a relatively mild grade of metamorphism, at temperatures of 350–500 °C (662–932 °F) and pressures of 200–500 MPa (2,000–5,000 bar). The greenstone belts are surrounded by high-grade gneiss terrains showing highly deformed low-pressure, high-temperature (over 500 °C (932 °F)) metamorphism to

1122-707: Was stolen in April 1986, recovered by Glen Rock police in October 1986, and subsequently welded to the pole to discourage future sign thieves. Gneiss Gneisses are common in the ancient crust of continental shields . Some of the oldest rocks on Earth are gneisses, such as the Acasta Gneiss . In traditional English and North American usage, a gneiss is a coarse-grained metamorphic rock showing compositional banding ( gneissic banding ) but poorly developed schistosity and indistinct cleavage . In other words, it

1156-464: Was used as a reference point in Native American land deeds that were still on the books as late as 1912. As of 1928, the rock was the only remaining fixed marker that had been used to delineate the colonial boundary dividing East Jersey from West Jersey. About half of the Glen Rock remained submerged under soil until 1910, when soil was gradually excavated to properly grade streets near

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