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Priddy Caves
Priddy Caves () is an Area: 67.6 hectare (167.0 acre) geological Site of Special Scientific Interest at Priddy in the Mendip Hills, Somerset, notified in 1965. The entrance to St Cuthbert's Swallet is incorporated in the adjacent Priddy Pools SSSI. The Priddy Caves System contains about 16 km of surveyed cave passages divided between a number of major and minor networks. All the caves are sink hole systems, fed by sink holes at the ground surface. In all the caves, the detailed disposition and form of the passages can be seen clearly to have followed marked lines of natural weakness in the rocks. The three largest networks, Swildon's Hole, St Cuthbert's Swallet and Eastwater Cavern exceed 100 metres in depth. Swildon's Hole is a world-famous example of a shallow depth phreatic cave, which shows a very well developed dendritic pattern of drainage and contains extensive clastic and stalagmite fills. Hunter's Hole is an excellent example of a shaft complex draining ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hectare
The hectare (; SI symbol: ha) is a non-SI metric unit of area equal to a square with 100-metre sides (1 hm2), or 10,000 m2, and is primarily used in the measurement of land. There are 100 hectares in one square kilometre. An acre is about and one hectare contains about . In 1795, when the metric system was introduced, the ''are'' was defined as 100 square metres, or one square decametre, and the hectare ("hecto-" + "are") was thus 100 ''ares'' or km2 (10,000 square metres). When the metric system was further rationalised in 1960, resulting in the International System of Units (), the ''are'' was not included as a recognised unit. The hectare, however, remains as a non-SI unit accepted for use with the SI and whose use is "expected to continue indefinitely". Though the dekare/decare daa (1,000 m2) and are (100 m2) are not officially "accepted for use", they are still used in some contexts. Description The hectare (), although not a unit of SI, i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phreatic
''Phreatic'' is a term used in hydrology to refer to aquifers, in speleology to refer to cave passages, and in volcanology to refer to a type of volcanic eruption. Hydrology The term phreatic (the word originates from the Greek , meaning "well" or "spring") is used in hydrology and the earth sciences to refer to matters relating to ground water (an aquifer) below the water table. The term 'phreatic surface' indicates the location where the pore water pressure is under atmospheric conditions (i.e. the pressure head is zero). This surface normally coincides with the water table. The slope of the phreatic surface is assumed to indicate the direction of ground water movement in an unconfined aquifer. The phreatic zone, below the phreatic surface where rock and soil is saturated with water, is the counterpart of the vadose zone, or unsaturated zone, above. Unconfined aquifers are also referred to as phreatic aquifers because their upper boundary is provided by the phreatic surface ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sites Of Special Scientific Interest In Somerset
__NOTOC__ This is a list of the Sites of Special Scientific Interest (SSSIs) in Somerset, England, United Kingdom. In England the body responsible for designating SSSIs is Natural England Natural England is a non-departmental public body in the United Kingdom sponsored by the Department for Environment, Food and Rural Affairs. It is responsible for ensuring that England's natural environment, including its land, flora and fauna, ..., which chooses a site because of its fauna, plant, flora, geology, geological or physiographical features. There are 127 sites designated in this Area of Search, of which 83 have been designated due to their biological interest, 35 due to their geological interest, and 9 for both. Natural England took over the role of designating and managing SSSIs from English Nature in October 2006 when it was formed from the amalgamation of English Nature, parts of the Countryside Agency and the Rural Development Service. Natural England, like its predecessor, u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caves Of The Mendip Hills
The caves of the Mendip Hills are formed by the particular geology of the Mendip Hills: large areas of limestone worn away by water makes it a national centre for caving. The hills conceal the largest underground river system in Britain. Geology The hills consist of anticlines of Carboniferous Limestone lying over Devonian Old Red Sandstone, with the sandstone exposed on the summits. When a surface stream running off the sandstone reaches the limestone it sinks below ground through a " swallet", (also known locally as a "slocker"), continuing on its way down towards sea level by enlarging existing cracks in the rock to form caves, and reappearing at the base of the limestone outcrop. As the water changes route within the hill some caves (or parts of caves) are left dry. There is a characteristic type of Mendip cave, in which there is an initially steep descent, and then a more level stretch ending in a "sump" as the cave reaches and descends below the prevailing water table. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ice Ages
An ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages and greenhouse periods, during which there are no glaciers on the planet. Earth is currently in the Quaternary glaciation. Individual pulses of cold climate within an ice age are termed ''glacial periods'' (or, alternatively, ''glacials, glaciations, glacial stages, stadials, stades'', or colloquially, ''ice ages''), and intermittent warm periods within an ice age are called ''interglacials'' or ''interstadials''. In glaciology, ''ice age'' implies the presence of extensive ice sheets in both northern and southern hemispheres. By this definition, Earth is currently in an interglacial period—the Holocene. The amount of anthropogenic greenhouse gases emitted into Earth's oceans and atmosphere is predicted to prevent the next glacial period for the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geologist
A geologist is a scientist who studies the solid, liquid, and gaseous matter that constitutes Earth and other terrestrial planets, as well as the processes that shape them. Geologists usually study geology, earth science, or geophysics, although backgrounds in physics, chemistry, biology, and other sciences are also useful. Field research (field work) is an important component of geology, although many subdisciplines incorporate laboratory and digitalized work. Geologists can be classified in a larger group of scientists, called geoscientists. Geologists work in the energy and mining sectors searching for natural resources such as petroleum, natural gas, precious and base metals. They are also in the forefront of preventing and mitigating damage from natural hazards and disasters such as earthquakes, volcanoes, tsunamis and landslides. Their studies are used to warn the general public of the occurrence of these events. Geologists are also important contributors to climate ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hunter's Hole
Hunter's Hole (or Hunters' Hole) is a cave in the Mendip Hills in Somerset, England. It is behind a pub, known as the Hunters Lodge Inn just outside Priddy where visitors can park. It is accessed via a permanent ladder, about 100m behind the pub in a small dip between some trees. The main cave was first entered after digging by Wessex and BEC cavers in 1954. The cave itself consists of a series of shafts down into the main chamber, named the "railway tunnel". Due to the cave mainly being the ascent and descent, it is used to practise single rope technique (SRT). It is part of the Priddy Caves Site of Special Scientific Interest and described as "an excellent example of a shaft complex draining a closed depression. The roof of the main shaft shows a variety of features such as soil and boulder bridges and scalloped and speleothem lined rifts, all draining the surface depression. This cave differs from the others at Priddy in apparently not having formed as a stream swallet." ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stalagmite
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] |
Clastic
Clastic rocks are composed of fragments, or clasts, of pre-existing minerals and rock. A clast is a fragment of geological detritus,Essentials of Geology, 3rd Ed, Stephen Marshak, p. G-3 chunks, and smaller grains of rock broken off other rocks by physical weathering.Essentials of Geology, 3rd Ed, Stephen Marshak, p. G-5 Geologists use the term clastic to refer to sedimentary rocks and particles in sediment transport, whether in suspension or as bed load, and in sediment deposits. Sedimentary clastic rocks Clastic sedimentary rocks are rocks composed predominantly of broken pieces or ''clasts'' of older weathered and eroded rocks. Clastic sediments or sedimentary rocks are classified based on grain size, clast and cementing material (matrix) composition, and texture. The classification factors are often useful in determining a sample's environment of deposition. An example of clastic environment would be a river system in which the full range of grains being transported by th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dendritic
Dendrite derives from the Greek word "dendron" meaning ( "tree-like"), and may refer to: Biology *Dendrite, a branched projection of a neuron *Dendrite (non-neuronal), branching projections of certain skin cells and immune cells Physical * Dendrite (metal), a characteristic tree-like structure of crystals growing as molten metal freezes *Dendrite (mathematics), a locally connected continuum that contains no simple closed curves *Dendrite (crystal), a crystal that develops with a typical multi-branching tree-like form *Dendrimer, a repetitively branched molecule Software * Dendrite (matrix), a server for the matrix protocol written in Go Brand *Dendrite (adhesive) Dendrite is a contact adhesive and rubber cement brand marketed in South Asia, mainly in Northeast India, Bangladesh and Bhutan. Products The adhesive is marketed in glue sticks, glue tubes and in cans. Dendrite holds 80% of the market share ..., a brand of contact cement from India and South Asia See also ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eastwater Cavern
Eastwater Cavern is a cave near Priddy in the limestone of the Mendip Hills, in Somerset, England. It is also known as Eastwater Swallet. It was first excavated in April 1902 by a team led by Herbert E. Balch composed of paid labourers and volunteers from the Wells Natural History Society. Progress was initially slow, but by February 1903 Balch and Willcox had discovered substantial passage, following the streamway down to the bottom of the cave. Dolphin Pot was dug in 1940 by the Wessex Cave Club, with Primrose Pot following in 1950. West End series was the most recent significant discovery, in 1983. On 28 August 1910 severe flooding rendered the boulder ruckles unstable, and the bottom of the cave was not reached again for another three years. The cavern was the site of a fatal accident in 1960, when Alan Hartnell was hit by rock-fall. Several areas of the boulder chokes remain unstable. Dolphin ladder pitch also suffered a rock fall and was blocked by a sofa-sized boul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geological 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 b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
