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Otter Hole
Otter Hole is perhaps one of the best decorated caves in Britain. Located on the Wales–England border just north of Chepstow, the cave runs from the banks of the tidal River Wye under the Chepstow Racecourse and onwards through various chambers, each rich with cave formations. Because of its importance as one of the finest examples of decorated caverns in Europe, access is restricted and is managed by the Royal Forest of Dean Caving Club on behalf of the landowner. Description The entrance to the cave is on the banks of the Wye through a gated doorway at the foot of a bluff. This is locked as a precaution against illegal entry to the cave, to protect the rare forms inside the cave and to prevent anyone wandering into the cave and being trapped accidentally as the cave floods with the tide. After a short crawl with few squeezes the passage opens out to a 'beach' where the tidal sump blocks access. At low tide this sump drains quickly and noisily, becoming passable as a 'd ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
St Arvans
St. Arvans (Welsh: ''Sain Arfan'' or ''Llanarfan'') is a village and community (parish) in Monmouthshire, south east Wales, United Kingdom. It is located two miles north west of Chepstow, close to Chepstow Racecourse, Piercefield House and the Wye Valley AONB. Connected by a Segregated Bicycle Path to the edge of Chepstow. History and amenities The village church is named after St. Arvan. According to tradition he was a 9th-century hermit who supported himself by fishing for salmon in the River Wye, and drowned when his coracle capsized. The circular nature of the churchyard suggests that the church may be a Celtic foundation. There are remains of a Celtic cross of the period, and also part of an apparently Saxon doorway, but essentially the original church was late Norman in date. By 1254 it belonged to the small priory of St. Kingsmark or Cynmarch. It was enlarged between 1813 and 1823, and extensive restoration work was carried out in the 1880s and again in the 1980s. The oc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Estuarine Mud
Bay mud consists of thick deposits of soft, unconsolidated silty clay, which is saturated with water; these soil layers are situated at the bottom of certain estuaries, which are normally in temperate regions that have experienced cyclical glacial cycles. Example locations are Cape Cod Bay, Chongming Dongtan Reserve in Shanghai, China, Banc d'Arguinpreserve in Mauritania, The Bristol Channel in the United Kingdom, Mandø Island in the Wadden Sea in Denmark, Florida Bay, San Francisco Bay, Bay of Fundy, Casco Bay, Penobscot Bay, and Morro Bay. Bay mud manifests low shear strength, high compressibility and low permeability, making it hazardous to build upon in seismically active regions like the San Francisco Bay Area. Typical bulk density of bay mud is approximately 1.3 grams per cubic centimetre. Bay muds often have a high organic content, consisting of decayed organisms at lower depths, but may also contain living creatures when they occur at the upper soil layer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Landforms Of Monmouthshire
A landform is a natural or anthropogenic land feature on the solid surface of the Earth or other planetary body. Landforms together make up a given terrain, and their arrangement in the landscape is known as topography. Landforms include hills, mountains, canyons, and valleys, as well as shoreline features such as bays, peninsulas, and seas, including submerged features such as mid-ocean ridges, volcanoes, and the great ocean basins. Physical characteristics Landforms are categorized by characteristic physical attributes such as elevation, slope, orientation, stratification, rock exposure and soil type. Gross physical features or landforms include intuitive elements such as berms, mounds, hills, ridges, cliffs, valleys, rivers, peninsulas, volcanoes, and numerous other structural and size-scaled (e.g. ponds vs. lakes, hills vs. mountains) elements including various kinds of inland and oceanic waterbodies and sub-surface features. Mountains, hills, plateaux, and plains are the fou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caves Of Wales
A cave or cavern is a natural void in the ground, specifically a space large enough for a human to enter. Caves often form by the weathering of rock and often extend deep underground. The word ''cave'' can refer to smaller openings such as sea caves, rock shelters, and grottos, that extend a relatively short distance into the rock and they are called ''exogene'' caves. Caves which extend further underground than the opening is wide are called ''endogene'' caves. Speleology is the science of exploration and study of all aspects of caves and the cave environment. Visiting or exploring caves for recreation may be called ''caving'', ''potholing'', or ''spelunking''. Formation types The formation and development of caves is known as ''speleogenesis''; it can occur over the course of millions of years. Caves can range widely in size, and are formed by various geological processes. These may involve a combination of chemical processes, erosion by water, tectonic forces, microorganism ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Site Of Special Scientific Interest
A Site of Special Scientific Interest (SSSI) in Great Britain or an Area of Special Scientific Interest (ASSI) in the Isle of Man and Northern Ireland is a conservation designation denoting a protected area in the United Kingdom and Isle of Man. SSSI/ASSIs are the basic building block of site-based nature conservation legislation and most other legal nature/geological conservation designations in the United Kingdom are based upon them, including national nature reserves, Ramsar sites, Special Protection Areas, and Special Areas of Conservation. The acronym "SSSI" is often pronounced "triple-S I". Selection and conservation Sites notified for their biological interest are known as Biological SSSIs (or ASSIs), and those notified for geological or physiographic interest are Geological SSSIs (or ASSIs). Sites may be divided into management units, with some areas including units that are noted for both biological and geological interest. Biological Biological SSSI/ASSIs may ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helictite
A helictite is a speleothem (cave-formed mineral) found in a limestone cave that changes its axis from the vertical at one or more stages during its growth. Helictites have a curving or angular form that looks as if they were grown in zero gravity. They are most likely the result of capillary forces acting on tiny water droplets, a force often strong enough at this scale to defy gravity. Helictites are, perhaps, the most delicate of cave formations. They are usually made of needle-form calcite and aragonite. Helictite forms have been described in several types: ribbon helictites, saws, rods, butterflies, "hands", curly-fries, and "clumps of worms". They typically have radial symmetry. They can be easily crushed or broken by the slightest touch. Because of this, helictites are rarely seen within arm's reach in tourist caves. Timpanogos Cave National Monument in Utah has one of the largest collections of these formations in the world. Large numbers are also in the Jenolan Caves ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Soda Straw
A soda straw (or simply straw) is a speleothem in the form of a hollow mineral cylindrical tube. They are also known as tubular stalactites. Soda straws grow in places where water leaches slowly through cracks in rock, such as on the roofs of caves. Soda straws in caves rarely grow more than a few millimetres per year and may average one tenth of a millimetre per year.Hill, C A, and Forti, P, (1997). "Speleothem Growth Rates", Cave Minerals of the World, (2nd edition). untsville, Alabama: National Speleological Society Inc.pp 285 - 287 A soda straw can turn into a stalactite if the hole at the bottom is blocked, or if the water begins flowing on the outside surface of the hollow tube. Soda straws can also form outside the cave environment on exposed concrete surfaces as a type of calthemite, growing significantly faster than those formed on rock. Formation These tubes form when calcium carbonate or calcium sulfate dissolved in the water comes out of solution and is deposi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arsenic
Arsenic is a chemical element with the symbol As and atomic number 33. Arsenic occurs in many minerals, usually in combination with sulfur and metals, but also as a pure elemental crystal. Arsenic is a metalloid. It has various allotropes, but only the gray form, which has a metallic appearance, is important to industry. The primary use of arsenic is in alloys of lead (for example, in car batteries and ammunition). Arsenic is a common n-type dopant in semiconductor electronic devices. It is also a component of the III-V compound semiconductor gallium arsenide. Arsenic and its compounds, especially the trioxide, are used in the production of pesticides, treated wood products, herbicides, and insecticides. These applications are declining with the increasing recognition of the toxicity of arsenic and its compounds. A few species of bacteria are able to use arsenic compounds as respiratory metabolites. Trace quantities of arsenic are an essential dietary element in rats, ham ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stalagmites
A stalagmite (, ; from the Greek , from , "dropping, trickling") is a type of rock formation that rises from the floor of a cave due to the accumulation of material deposited on the floor from ceiling drippings. Stalagmites are typically composed of calcium carbonate, but may consist of lava, mud, peat, pitch, sand, sinter, and amberat (crystallized urine of pack rats). The corresponding formation hanging down from the ceiling of a cave is a stalactite. Mnemonics have been developed for which word refers to which type of formation; one is that ''stalactite'' has a C for "ceiling", and ''stalagmite'' has a G for "ground", another is that, as with ants in the pants, the mites go up and the tights (tites) come down. Formation and type Limestone stalagmites The most common stalagmites are speleothems, which usually form in limestone caves. Stalagmite formation occurs only under certain pH conditions within the cavern. They form through deposition of calcium carbonate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boulder Choke
A boulder choke is a collection of large rocks or rubble that obstructs a shaft or passage in a cave or mine. In order to progress through passages cavers often need to negotiate or clear boulder chokes. Boulder chokes can be formed by rockfall, stream deposition, or mining debris. Due to the nature of their formation boulder chokes may be unstable and can prove difficult to navigate and map due to their complexity. In order to clear a boulder choke the rocks obstructing the passage may need to be removed, often requiring breaking up first either mechanically or using a small explosive. The Three Counties System became the longest cave in the UK when cavers succeeded in clearing a route through a boulder choke for to connect two known cave systems, an exercise that took three years. Boulder chokes can be hazardous, as unstable boulders can unexpectedly move, potentially crushing or trapping cavers. In May 1988, for example, three cavers were killed in a boulder choke in Ease Gil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sump (cave)
A sump, or siphon, is a passage in a cave that is submerged under water. A sump may be static, with no inward or outward flow, or active, with continuous through-flow. Static sumps may also be connected underwater to active stream passage. When short in length, a sump may be called a duck, however this can also refer to a section or passage with some (minimal) airspace above the water. Depending on hydrological factors specific to a cave – such as the sea tide, changes in river flow, or the relationship with the local water table – sumps and ducks may fluctuate in water level and depth (and sometimes in length, due to the shape of adjacent passage). Exploration past a sump Diving Short sumps may be passed simply by holding one's breath while ducking through the submerged section (for example, Sump 1 in Swildon's Hole). This is known as "free diving" and can only be attempted if the sump is known to be short and not technically difficult (e.g. constricted or requiring nav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monmouthshire
Monmouthshire ( cy, Sir Fynwy) is a county in the south-east of Wales. The name derives from the historic county of the same name; the modern county covers the eastern three-fifths of the historic county. The largest town is Abergavenny, with other towns and large villages being: Caldicot, Chepstow, Monmouth, Magor and Usk. It borders Torfaen, Newport and Blaenau Gwent to the west; Herefordshire and Gloucestershire to the east; and Powys to the north. Historic county The historic county of Monmouthshire was formed from the Welsh Marches by the Laws in Wales Act 1535 bordering Gloucestershire to the east, Herefordshire to the northeast, Brecknockshire to the north, and Glamorgan to the west. The Laws in Wales Act 1542 enumerated the counties of Wales and omitted Monmouthshire, implying that the county was no longer to be treated as part of Wales. However, for all purposes Wales had become part of the Kingdom of England, and the difference had little practical effect. F ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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