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Craig Cerrig-gleisiad
Craig Cerrig-gleisiad is a subsidiary summit of Fan Fawr in the Fforest Fawr section of the Brecon Beacons National Park, South Wales. It makes up half of the Craig Cerrig-gleisiad and Fan Frynych National Nature Reserve with its sister peak Fan Frynych. The summit is marked by a pile of stones, and sits on the edge of steep north facing cliffs which provide one of the few habitats for Arctic–alpine plants this far south in the British Isles. To the south-west is Fan Llia. Geology The outstanding feature of the mountain is the L-shaped glacial cwm which faces to the northeast. Its modern form is considered to be the result of a complex history of both glacial action and rock-slope failure, a portion of the west wall having collapsed after the main part of the last ice age. Some of the debris was re-worked during the Loch Lomond Stadial and parts stretch as far as the A470 road.Richard Shakesby, Classic Landforms of the Brecon Beacons, 2002, Geological Association Landform G ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fan Frynych
Fan Frynych is the northernmost peak of the Fforest Fawr massif in the Brecon Beacons National Park, South Wales. It is classed as a subsidiary summit of Fan Fawr and makes up half of the Craig Cerrig-gleisiad and Fan Frynych National Nature Reserve with its sister peak Craig Cerrig-gleisiad. The summit is marked by a trig point, where the northern face of Craig Cerrig-gleisiad can be viewed. Geology The upper parts of the mountain are formed from brown-coloured sandstones of the Senni Formation. At lower level and hence older, and forming the lower northern slopes, though largely unseen, are the mudstones of the St Maughans Formation. Both are units of the Lower Old Red Sandstone of early Devonian age. Though locally variable, the rock strata dip generally towards the southeast. The northeastern flank of the mountain is defined by a NE-SW aligned geological fault, the Cribarth Fault downthrowing to the southeast, which forms a part of the Swansea Valley Disturbance. Large parts ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arctic–alpine
An Arctic–alpine taxon is one whose natural distribution includes the Arctic and more southerly mountain ranges, particularly the Alps. The presence of identical or similar taxa in both the tundra of the far north, and high mountain ranges much further south is testament to the similar environmental conditions found in the two locations. Arctic–alpine plants, for instance, must be adapted to the low temperatures, extremes of temperature, strong winds and short growing season; they are therefore typically low-growing and often form mats or cushions to reduce water loss through evapotranspiration. It is often assumed that an organism which currently has an Arctic–alpine distribution was, during colder periods of the Earth's history (such as during the Pleistocene glaciations), widespread across the area between the Arctic and the Alps. This is known from pollen records to be true for ''Dryas octopetala'', for instance. In other cases, the disjunct distribution may be the result ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mountains And Hills Of Powys
A mountain is an elevated portion of the Earth's crust, generally with steep sides that show significant exposed bedrock. Although definitions vary, a mountain may differ from a plateau in having a limited summit area, and is usually higher than a hill, typically rising at least 300 metres (1,000 feet) above the surrounding land. A few mountains are isolated summits, but most occur in mountain ranges. Mountains are formed through tectonic forces, erosion, or volcanism, which act on time scales of up to tens of millions of years. Once mountain building ceases, mountains are slowly leveled through the action of weathering, through slumping and other forms of mass wasting, as well as through erosion by rivers and glaciers. High elevations on mountains produce colder climates than at sea level at similar latitude. These colder climates strongly affect the ecosystems of mountains: different elevations have different plants and animals. Because of the less hospitable terrain and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peregrine Falcons
The peregrine falcon (''Falco peregrinus''), also known as the peregrine, and historically as the duck hawk in North America, is a cosmopolitan bird of prey (raptor) in the family Falconidae. A large, crow-sized falcon, it has a blue-grey back, barred white underparts, and a black head. The peregrine is renowned for its speed, reaching over during its characteristic hunting stoop (high-speed dive), making it the fastest bird in the world, as well as the fastest member of the animal kingdom. According to a ''National Geographic'' TV program, the highest measured speed of a peregrine falcon is . As is typical for bird-eating raptors, peregrine falcons are sexually dimorphic, with females being considerably larger than males. The peregrine's breeding range includes land regions from the Arctic tundra to the tropics. It can be found nearly everywhere on Earth, except extreme polar regions, very high mountains, and most tropical rainforests; the only major ice-free landmass from w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Old Red Sandstone
The Old Red Sandstone is an assemblage of rocks in the North Atlantic region largely of Devonian age. It extends in the east across Great Britain, Ireland and Norway, and in the west along the northeastern seaboard of North America. It also extends northwards into Greenland and Svalbard. These areas were a part of the ancient continent of Euramerica, Euramerica/Laurussia. In Britain it is a lithostratigraphy, lithostratigraphic unit (a sequence of rock strata) to which Stratigraphy, stratigraphers accord Geological unit#Lithostratigraphic units, supergroup status and which is of considerable importance to early paleontology. For convenience the short version of the term, ORS is often used in literature on the subject. The term was coined to distinguish the sequence from the younger New Red Sandstone which also occurs widely throughout Britain. Sedimentology The Old Red Sandstone describes a suite of sedimentary rocks deposited in a variety of environments during the Devonian ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Devonian
The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, where rocks from this period were first studied. The first significant adaptive radiation of life on dry land occurred during the Devonian. Free-sporing vascular plants began to spread across dry land, forming extensive forests which covered the continents. By the middle of the Devonian, several groups of plants had evolved leaves and true roots, and by the end of the period the first seed-bearing plants appeared. The arthropod groups of myriapods, arachnids and hexapods also became well-established early in this period, after starting their expansion to land at least from the Ordovician period. Fish reached substantial diversity during this time, leading the Devonian to often be dubbed the Age of Fishes. The placoderms began dominating ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Loch Lomond Stadial
The Younger Dryas (c. 12,900 to 11,700 years BP) was a return to glacial conditions which temporarily reversed the gradual climatic warming after the Last Glacial Maximum (LGM, c. 27,000 to 20,000 years BP). The Younger Dryas was the last stage of the Pleistocene epoch (c. 2,580,000 to 11,700 years BP) and it preceded the current, warmer Holocene epoch. The Younger Dryas was the most severe and long lasting of several interruptions to the warming of the Earth's climate, and it was preceded by the Late Glacial Interstadial (c. 14,670 to 12,900 BP). The change was relatively sudden, taking place in decades, and it resulted in a decline of temperatures in Greenland by 4~10 °C (7.2~18 °F), and advances of glaciers and drier conditions over much of the temperate Northern Hemisphere. A number of theories have been put forward about the cause, and the most widely supported by scientists is that the Atlantic meridional overturning circulation, which transports warm water fro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glacial
A glacial period (alternatively glacial or glaciation) is an interval of time (thousands of years) within an ice age that is marked by colder temperatures and glacier advances. Interglacials, on the other hand, are periods of warmer climate between glacial periods. The Last Glacial Period ended about 15,000 years ago. The Holocene is the current interglacial. A time with no glaciers on Earth is considered a greenhouse climate state. Quaternary Period Within the Quaternary, which started about 2.6 million years before present, there have been a number of glacials and interglacials. At least eight glacial cycles have occurred in the last 740,000 years alone. Penultimate Glacial Period The Penultimate Glacial Period (PGP) is the glacial period that occurred before the Last Glacial Period. It began about 194,000 years ago and ended 135,000 years ago, with the beginning of the Eemian interglacial. Last Glacial Period The last glacial period was the most recent glacial period ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cirque
A (; from the Latin word ') is an amphitheatre-like valley formed by glacial erosion. Alternative names for this landform are corrie (from Scottish Gaelic , meaning a pot or cauldron) and (; ). A cirque may also be a similarly shaped landform arising from fluvial erosion. The concave shape of a glacial cirque is open on the downhill side, while the cupped section is generally steep. Cliff-like slopes, down which ice and glaciated debris combine and converge, form the three or more higher sides. The floor of the cirque ends up bowl-shaped, as it is the complex convergence zone of combining ice flows from multiple directions and their accompanying rock burdens. Hence, it experiences somewhat greater erosion forces and is most often overdeepened below the level of the cirque's low-side outlet (stage) and its down-slope (backstage) valley. If the cirque is subject to seasonal melting, the floor of the cirque most often forms a tarn (small lake) behind a dam, which marks the down ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Craig Cerrig Gleisiad National Nature Reserve
__NOTOC__ Craig may refer to: Geology *Craig (landform), a rocky hill or mountain often having large casims or sharp intentations. People (and fictional characters) *Craig (surname) *Craig (given name) Places Scotland *Craig, Angus, aka Barony of Craigie United States *Craig, Alaska, a city *Craig, Colorado, a city *Craig, Indiana, an unincorporated place *Craig, Iowa, a city *Craig, Missouri, a city *Craig, Montana, an unincorporated place *Craig, Nebraska, a village *Craig, Ohio, an unincorporated community *Craig County, Virginia *Craig County, Oklahoma *Craig Township (other) (two places) Other uses *Craig (song) *Craig Electronics, a consumer electronics company * Craig Broadcast Systems, later Craig Media and finally Craig Wireless, a defunct Canadian media and communication company *Clan Craig, a Scottish clan *Craig tube, a piece of scientific apparatus See also *''Craig v. Boren'', a U.S. Supreme Court case * Justice Craig (other) *Craic ''Crai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fan Llia
Fan Llia is a subsidiary summit of Fan Fawr in the Fforest Fawr section of the Brecon Beacons National Park, Wales. In common with other peaks in the Fforest Fawr uplands it lies within the county of Powys. The hill has the form of a broad ridge aligned south-south-west to north-north-east peaking at an altitude of 632 m. It has a subsidiary top to the north which is known as Fan Dringarth and which attains a height of 617 m. Its broad northern ridge is eventually truncated by the cliffs of Craig Cwm-du. A number of features of archaeological interest are to be found on its flanks including several house platforms. Geology The hill is formed largely from sandstones of the Brownstones Formation of the Old Red Sandstone dating from the Devonian period. Its southernmost slopes (around Cefn Perfedd) are formed in Plateau Beds Formation sandstones and an area in the north-east is underlain by sandstones and mudstones of the Senni Beds Formation. Rock exposures are infrequent − ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
British Isles
The British Isles are a group of islands in the North Atlantic Ocean off the north-western coast of continental Europe, consisting of the islands of Great Britain, Ireland, the Isle of Man, the Inner and Outer Hebrides, the Northern Isles, and over six thousand smaller islands."British Isles", ''Encyclopædia Britannica''. They have a total area of and a combined population of almost 72 million, and include two sovereign states, the Republic of Ireland (which covers roughly five-sixths of Ireland), and the United Kingdom of Great Britain and Northern Ireland. The Channel Islands, off the north coast of France, are normally taken to be part of the British Isles, even though they do not form part of the archipelago. The oldest rocks are 2.7 billion years old and are found in Ireland, Wales and the northwest of Scotland. During the Silurian period, the north-western regions collided with the south-east, which had been part of a separate continental landmass. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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