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Isle Of Gigha
Gigha (; gd, Giogha, italic=yes; sco, Gigha) or the Isle of Gigha (and formerly Gigha Island) is an island off the west coast of Kintyre in Scotland. The island forms part of Argyll and Bute and has a population of 163 people. The climate is mild with higher than average sunshine hours and the soils are fertile. The main settlement is Ardminish. Gigha has been inhabited continuously since Prehistory, prehistoric times. It may have had an important role during the Kingdom of Dalriada and is the ancestral home of Clan MacNeill. It fell under the control of the Norse and the Lords of the Isles before becoming incorporated into modern Scotland and saw a variety of conflicts during the Middle Ages, medieval period. The population of Gigha peaked at over 700 in the eighteenth century, but during the 20th century the island had numerous owners, which caused various problems in developing the island. By the beginning of the 21st century the population had fallen to 98. However a "comm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hákonar Saga Hákonarsonar
''Hákonar saga Hákonarsonar'' ("The Saga of Haakon Haakonarson") or ''Hákonar saga gamla'' ("The Saga of Old Haakon") is an Old Norse Kings' Saga, telling the story of the life and reign of King Haakon Haakonarson of Norway. Content and style The circumstances of the saga's composition are exceptionally well understood, as they are recorded in some detail in '' Sturlunga saga'' (particularly ''Sturlu þáttr''): the saga was written in the 1260s (apparently 1264–65) by the Icelandic historian and chieftain Sturla Þórðarson (nephew of the noted historian Snorri Sturluson). Sturla Þórðarson was at the court of Haakon's son Magnus Lagabøte when Magnus learned of his father's death in Kirkwall in Orkney. Magnus is said to have immediately commissioned Sturla to write his father's saga. This was awkward for Sturla: 'King Hákon had instigated the death of Sturla's uncle, Snorri Sturluson, in 1241. Sturla rightly regarded Hákon as his most dangerous enemy, for he had steadf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Semipelite
A pelite (Greek: ''pelos'', "clay") or metapelite is a metamorphosed fine-grained sedimentary rock, i.e. mudstone or siltstone. The term was earlier used by geologists to describe a clay-rich, fine-grained clastic sediment or sedimentary rock, i.e. mud or a mudstone, the metamorphosed version of which would technically have been a ''metapelite''. It was equivalent to the now little-used Latin-derived term lutite.Potter, P.E., J.B. Maynard, and P.J. Depetris (2005) ''Muds and Mudstones.'' New York, New York, Springer. 279 pp. Neuendorf, K.K.E., J.P. Mehl, Jr., and J.A. Jackson, eds. (2005) ''Glossary of Geology'' (5th ed.). Alexandria, Virginia, American Geological Institute. 779 pp. A semipelite is defined in part as having similar chemical composition but being of a crystalloblastic nature. Pettijohn (1975) gives the following descriptive terms based on grain size, avoiding the use of terms such as clay or argillaceous which carry an implication of chemical composition. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pelite
A pelite (Greek: ''pelos'', "clay") or metapelite is a metamorphosed fine-grained sedimentary rock, i.e. mudstone or siltstone. The term was earlier used by geologists to describe a clay-rich, fine-grained clastic sediment or sedimentary rock, i.e. mud or a mudstone, the metamorphosed version of which would technically have been a ''metapelite''. It was equivalent to the now little-used Latin-derived term lutite.Potter, P.E., J.B. Maynard, and P.J. Depetris (2005) ''Muds and Mudstones.'' New York, New York, Springer. 279 pp. Neuendorf, K.K.E., J.P. Mehl, Jr., and J.A. Jackson, eds. (2005) ''Glossary of Geology'' (5th ed.). Alexandria, Virginia, American Geological Institute. 779 pp. A semipelite is defined in part as having similar chemical composition but being of a crystalloblastic nature. Pettijohn (1975) gives the following descriptive terms based on grain size, avoiding the use of terms such as clay or argillaceous which carry an implication of chemical composition. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grampian Mountains
The Grampian Mountains (''Am Monadh'' in Scottish Gaelic, Gaelic) is one of the three major mountain ranges in Scotland, that together occupy about half of Scotland. The other two ranges are the Northwest Highlands and the Southern Uplands. The Grampian range extends southwest to northeast between the Highland Boundary Fault and the Great Glen. The range includes many of the highest mountains in the British Isles, including Ben Nevis (whose peak contains the highest point in the British Isles at above sea level) and Ben Macdhui (Scotland), Ben Macdui (whose peak contains second-highest at ). A number of rivers and streams rise in the Grampians, including the River Tay, Tay, River Spey, Spey, Cowie Water, Burn of Muchalls, Burn of Pheppie, Burn of Elsick, Cairnie Burn, River Don, Aberdeenshire, Don, River Dee, Aberdeenshire, Dee and River South Esk, Esk. The area is generally sparsely populated. There is some ambiguity about the extent of the range, and until the nineteenth c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dalradian
The Dalradian Supergroup (informally and traditionally the Dalradian) is a stratigraphic unit (a sequence of rock strata) in the lithostratigraphy of the Grampian Highlands of Scotland and in the north and west of Ireland. The diverse assemblage of rocks which constitute the supergroup extend across Scotland from Islay in the west to Fraserburgh in the east and are confined by the Great Glen Fault to the northwest and the Highland Boundary Fault to the southeast. Much of Shetland east of the Walls Boundary Fault is also formed from Dalradian rocks. Dalradian rocks extend across the north of Ireland from County Antrim in the north east to Clifden on the Atlantic coast, although obscured by later Palaeogene lavas and tuffs or Carboniferous rocks in large sections. Historical The land to the southeast of the Great Glen was the old Celtic region of Dál Riata (Dalriada), and in 1891 Archibald Geikie proposed the name Dalradian as a convenient provisional designation for the complic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Argyll Group
The Argyll Group is a thick sequence of metamorphosed Neoproterozoic sedimentary rocks that outcrop across the Central Highlands of Scotland, east of the Great Glen, as well as appearing in the north of Ireland. It is a subdivision of the Dalradian Supergroup and is itself divided into four units; from oldest to youngest these are the Islay, Easdale, Crinan and Tayvallich subgroups. Islay Subgroup The lower boundary of the Islay Subgroup and hence the Argyll Group as a whole is defined at the base of the Port Askaig tillite, a diamictite which displays limestone clasts overlain by quartzite and granite clasts. The tillite is thickest in its type area and on the Garvellachs. The Schiehallion Boulder Bed of the eastern Grampians correlates with this tillite. The tillite is overlain by the Bonahaven Dolomite and then the Jura Quartzite which can reach up to 5 km thick but which is more typically between 500 and 1000m thick. Psammites and pelites occur within the sequence in t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neoproterozoic
The Neoproterozoic Era is the unit of geologic time from 1 billion to 538.8 million years ago. It is the last era of the Precambrian Supereon and the Proterozoic Eon; it is subdivided into the Tonian, Cryogenian, and Ediacaran periods. It is preceded by the Mesoproterozoic Era and succeeded by the Paleozoic Era of the Phanerozoic Eon. The most severe glaciation known in the geologic record occurred during the Cryogenian, when ice sheets may have reached the equator and formed a " Snowball Earth". The earliest fossils of complex multicellular life are found in the Ediacaran Period. These organisms make up the Ediacaran biota, including the oldest definitive animals in the fossil record. According to Rino and co-workers, the sum of the continental crust formed in the Pan-African orogeny and the Grenville orogeny makes the Neoproterozoic the period of Earth's history that has produced most continental crust. Geology At the onset of the Neoproterozoic the supercontine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metasedimentary Rock
In geology, metasedimentary rock is a type of metamorphic rock. Such a rock was first formed through the deposition and solidification of sediment Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sand an .... Then, the rock was buried underneath subsequent rock and was subjected to high pressures and temperatures, causing the rock to recrystallize. The overall composition of a metasedimentary rock can be used to identify the original sedimentary rock, even where they have been subject to high-grade metamorphism and intense deformation. Types of metasedimentary rocks See also * References Metamorphic petrology {{petrology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sill (geology)
In geology, a sill is a tabular sheet intrusion that has intruded between older layers of sedimentary rock, beds of volcanic lava or tuff, or along the direction of foliation in metamorphic rock. A ''sill'' is a ''concordant intrusive sheet'', meaning that a sill does not cut across preexisting rock beds. Stacking of sills builds a sill complex . and a large magma chamber at high magma flux. In contrast, a dike is a discordant intrusive sheet, which does cut across older rocks. Sills are fed by dikes, except in unusual locations where they form in nearly vertical beds attached directly to a magma source. The rocks must be brittle and fracture to create the planes along which the magma intrudes the parent rock bodies, whether this occurs along preexisting planes between sedimentary or volcanic beds or weakened planes related to foliation in metamorphic rock. These planes or weakened areas allow the intrusion of a thin sheet-like body of magma paralleling the existing bedding pla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metamorphism
Metamorphism is the transformation of existing rock (the protolith) to rock with a different mineral composition or texture. Metamorphism takes place at temperatures in excess of , and often also at elevated pressure or in the presence of chemically active fluids, but the rock remains mostly solid during the transformation. Metamorphism is distinct from weathering or diagenesis, which are changes that take place at or just beneath Earth's surface. Various forms of metamorphism exist, including regional, contact, hydrothermal, shock, and dynamic metamorphism. These differ in the characteristic temperatures, pressures, and rate at which they take place and in the extent to which reactive fluids are involved. Metamorphism occurring at increasing pressure and temperature conditions is known as ''prograde metamorphism'', while decreasing temperature and pressure characterize ''retrograde metamorphism''. Metamorphic petrology is the study of metamorphism. Metamorphic petrologists re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Igneous Rock
Igneous rock (derived from the Latin word ''ignis'' meaning fire), or magmatic rock, is one of the three main The three types of rocks, rock types, the others being Sedimentary rock, sedimentary and metamorphic rock, metamorphic. Igneous rock is formed through the cooling and solidification of magma or lava. The magma can be derived from Partial melting, partial melts of existing rocks in either a Terrestrial planet, planet's mantle (geology), mantle or crust (geology), crust. Typically, the melting is caused by one or more of three processes: an increase in temperature, a decrease in pressure, or a change in composition. Solidification into rock occurs either below the surface as intrusive rocks or on the surface as extrusive (geology), extrusive rocks. Igneous rock may form with crystallization to form granular, crystalline rocks, or without crystallization to form Volcanic glass, natural glasses. Igneous rocks occur in a wide range of geological settings: shields, platforms ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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