periglacial

Carbon forms more than 50 percent by weight and more than 70 percent by volume of coal (this includes inherent moisture). This is dependent on coal rank, with higher rank coals containing less hydrogen, oxygen and nitrogen, until 95% purity of carbon is achieved at Anthracite rank and above. Graphite formed from coal is the end-product of the thermal and diagenetic conversion of plant matter (50% b ...

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Coal, Coal - Etymology and folklore, Coal - Composition, Coal - Creation, Coal - Types of coal, Coal - Uses, Coal - Coal as fuel, Coal - Coking and use of coke, Coal - Harmful effects of coal burning, Coal - Coal fires, Coal - World coal reserves

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It has been estimated that, as of 1996, there is around one exagram (1 × 1015 kg) of total coal reserves accessible using current mining technology, approximately half of it being hard coal. The energy value of all the world's coal is well over 100,000 quadrillion Btu (100 zettajoules). There probably is enough coal to last for 300 years. However, this estimate assumes no rise in population, and no increased use of coal to attempt to compensate for the depletion of natural gas and petroleum. A recent (2003) study by scientist Gre ...

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Coal, Coal - Etymology and folklore, Coal - Composition, Coal - Creation, Coal - Types of coal, Coal - Uses, Coal - Coal as fuel, Coal - Coking and use of coke, Coal - Harmful effects of coal burning, Coal - Coal fires, Coal - World coal reserves

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In the early nineteenth century, the A151 would have been called a cross-road2 since it runs across the pattern of these radial routes. As originally designated, it ran from the A15 at Bourne Market Place (TF095201), eastwards to Fleet Hargate, three kilometres east of Holbeach (TF393250), on the A17. Its present western section, between Colsterworth and Bourne, was part of the B676 road3. Road building and re-thinking of the road system have meant that nowadays, its western end is o ...

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A151 road, A151 road - The British Road Numbering System, A151 road - The A151: Summary, A151 road - Turnpike roads, A151 road - Toll gates, A151 road - The Condition of the turnpike roads, A151 road - The Terrain, A151 road - Description, A151 road - The Western End., A151 road - Corby Glen, A151 road - Edenham, A151 road - Bourne, A151 road - Pinchbeck, A151 road - In the Townlands, A151 road - Footnotes

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Stonehenge's fame has led to numerous efforts to recreate it, using a variety of different materials, around the world. Some have been carefully built as astronomically-aligned models whilst others have been examples of artistic expression or tourist attractions. There is a full-size replica of Stonehenge as it would have been before decay at Maryhill in Washington State, built by Sam Hill as a war memorial. It is even aligned to the midsummer sunrise, but to the true position of the sun at the virtual horizon, rather than the apparen ...

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Stonehenge, Stonehenge - Etymology, Stonehenge - Development of Stonehenge, Stonehenge - Before the monument, Stonehenge - Stonehenge 1, Stonehenge - Stonehenge 2, Stonehenge - Stonehenge 3i, Stonehenge - Stonehenge 3ii, Stonehenge - Stonehenge 3iii, Stonehenge - Stonehenge 3iv, Stonehenge - Stonehenge 3v, Stonehenge - Stonehenge 3vi, Stonehenge - After the monument, Stonehenge - Theories about Stonehenge, Stonehenge - Early interpretations, Stonehenge - Archaeoastronomy and Stonehenge, Stonehenge - The bluestones, Stonehenge - Stonehenge as part of a ritual landscape, Stonehenge - Construction techniques and design, Stonehenge - Alternative views, Stonehenge - Excavations at Stonehenge, Stonehenge - Myths and legends, Stonehenge - Recent history, Stonehenge - Laser scanning the Bronze Age dagger and axes at Stonehenge, Stonehenge - Replicas and derivative names

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Friar's Heel: The Heel Stone was once known as "Friar's Heel." A folk tale, which cannot be dated earlier than the seventeenth century, relates the origin of the name of this stone: The Devil bought the stones from a woman in Ireland, wrapped them up, and brought them to Salisbury plain. One of the stones fell into the Avon, the rest were carried to the plain. The Devil then cried out, "No-one will ever find out how these stones came here." A friar replied, "That's what you think!," whereupon the Devil threw one of the stones at him and struck him on the heel. The s ...

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Stonehenge, Stonehenge - Etymology, Stonehenge - Development of Stonehenge, Stonehenge - Before the monument, Stonehenge - Stonehenge 1, Stonehenge - Stonehenge 2, Stonehenge - Stonehenge 3i, Stonehenge - Stonehenge 3ii, Stonehenge - Stonehenge 3iii, Stonehenge - Stonehenge 3iv, Stonehenge - Stonehenge 3v, Stonehenge - Stonehenge 3vi, Stonehenge - After the monument, Stonehenge - Theories about Stonehenge, Stonehenge - Early interpretations, Stonehenge - Archaeoastronomy and Stonehenge, Stonehenge - The bluestones, Stonehenge - Stonehenge as part of a ritual landscape, Stonehenge - Construction techniques and design, Stonehenge - Alternative views, Stonehenge - Excavations at Stonehenge, Stonehenge - Myths and legends, Stonehenge - Recent history, Stonehenge - Laser scanning the Bronze Age dagger and axes at Stonehenge, Stonehenge - Replicas and derivative names

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By the beginning of the 20th century many of the bluestones were leaning precariously, probably due to the increase in curious visitors clambering on them during the nineteenth century. Additionally two of the trilithons had fallen over during the modern era. Three phases of conservation work were undertaken which righted unstable or fallen stones and carefully replaced them in their original positions using information from antiquarian drawings. If nothing else, this means that Stonehenge is not quite as timeless as its tourist publicity would suggest and that as with most historic monu ...

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Stonehenge, Stonehenge - Etymology, Stonehenge - Development of Stonehenge, Stonehenge - Before the monument, Stonehenge - Stonehenge 1, Stonehenge - Stonehenge 2, Stonehenge - Stonehenge 3i, Stonehenge - Stonehenge 3ii, Stonehenge - Stonehenge 3iii, Stonehenge - Stonehenge 3iv, Stonehenge - Stonehenge 3v, Stonehenge - Stonehenge 3vi, Stonehenge - After the monument, Stonehenge - Theories about Stonehenge, Stonehenge - Early interpretations, Stonehenge - Archaeoastronomy and Stonehenge, Stonehenge - The bluestones, Stonehenge - Stonehenge as part of a ritual landscape, Stonehenge - Construction techniques and design, Stonehenge - Alternative views, Stonehenge - Excavations at Stonehenge, Stonehenge - Myths and legends, Stonehenge - Recent history, Stonehenge - Laser scanning the Bronze Age dagger and axes at Stonehenge, Stonehenge - Replicas and derivative names

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Christopher Chippendale's Stonehenge Complete gives the derivation of Stonehenge as being from the Old English words "stān" meaning "stone", and either "hencg" meaning "hinge" (because the stone lintels hinge on the upright stones) or "hen(c)en" meaning "gallows" or "instrument of torture". Medieval gallows consisted of two uprights with a lintel joining them like Stonehenge's trilithons rather than t ...

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Stonehenge, Stonehenge - Etymology, Stonehenge - Development of Stonehenge, Stonehenge - Before the monument, Stonehenge - Stonehenge 1, Stonehenge - Stonehenge 2, Stonehenge - Stonehenge 3i, Stonehenge - Stonehenge 3ii, Stonehenge - Stonehenge 3iii, Stonehenge - Stonehenge 3iv, Stonehenge - Stonehenge 3v, Stonehenge - Stonehenge 3vi, Stonehenge - After the monument, Stonehenge - Theories about Stonehenge, Stonehenge - Early interpretations, Stonehenge - Archaeoastronomy and Stonehenge, Stonehenge - The bluestones, Stonehenge - Stonehenge as part of a ritual landscape, Stonehenge - Construction techniques and design, Stonehenge - Alternative views, Stonehenge - Excavations at Stonehenge, Stonehenge - Myths and legends, Stonehenge - Recent history, Stonehenge - Laser scanning the Bronze Age dagger and axes at Stonehenge, Stonehenge - Replicas and derivative names

Read more here: » Stonehenge: Encyclopedia II - Stonehenge - Etymology

The first recorded excavations at Stonehenge were carried out by William Cunnington and Richard Colt Hoare. In 1798, Cunnington investigated the pit beneath a recently fallen trilithon and in 1810, both men dug beneath the fallen Slaughter Stone and concluded that it had once stood up. They may have also excavated one of the Aubrey Holes beneath it. In 1839, one Captain Beamish dug around the Altar Stone and a little later Charles Darwin was granted permission by the Antrobus family who owned Stonehenge to hold a small excavation to test his ...

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Stonehenge, Stonehenge - Etymology, Stonehenge - Development of Stonehenge, Stonehenge - Before the monument, Stonehenge - Stonehenge 1, Stonehenge - Stonehenge 2, Stonehenge - Stonehenge 3i, Stonehenge - Stonehenge 3ii, Stonehenge - Stonehenge 3iii, Stonehenge - Stonehenge 3iv, Stonehenge - Stonehenge 3v, Stonehenge - Stonehenge 3vi, Stonehenge - After the monument, Stonehenge - Theories about Stonehenge, Stonehenge - Early interpretations, Stonehenge - Archaeoastronomy and Stonehenge, Stonehenge - The bluestones, Stonehenge - Stonehenge as part of a ritual landscape, Stonehenge - Construction techniques and design, Stonehenge - Alternative views, Stonehenge - Excavations at Stonehenge, Stonehenge - Myths and legends, Stonehenge - Recent history, Stonehenge - Laser scanning the Bronze Age dagger and axes at Stonehenge, Stonehenge - Replicas and derivative names

Read more here: » Stonehenge: Encyclopedia II - Stonehenge - Excavations at Stonehenge

Coal is formed from plant remains that have been compacted, hardened, chemically altered, and metamorphosed by heat and pressure over geologic time. Coal was formed in swamp ecosystems which persisted in lowland sedimentary basins similar to the peat swamps of Borneo and Kalimantan today. These swamp environments were formed during slow subsidence of passive continental margins, and most seem to have formed adjacent to estuarine and marine sediments suggesting that they may have ...

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Coal, Coal - Etymology and folklore, Coal - Composition, Coal - Creation, Coal - Types of coal, Coal - Uses, Coal - Coal as fuel, Coal - Coking and use of coke, Coal - Harmful effects of coal burning, Coal - Coal fires, Coal - World coal reserves

Read more here: » Coal: Encyclopedia II - Coal - Creation

At present the surface of the planet Mars is too cold to permit pooling of liquid water on the surface. However geologic evidence appears to confirm that ancient lakes once formed on the surface. It is also possible that volcanic activity on Mars will occasionally melt the subsurface ice, forming large lakes. Under current conditions this water will quickly evaporate or freeze unless insulated in som ...

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Lake, Lake - Origin of natural lakes, Lake - Characteristics, Lake - Types of lakes, Lake - Artificial lakes, Lake - Abiotic and biotic limnology, Lake - How lakes disappear, Lake - Extraterrestrial lakes, Lake - Notable lakes

Read more here: » Lake: Encyclopedia II - Lake - Extraterrestrial lakes

A lake may be infilled with deposited sediment, and gradually, the lake becomes a wetland, such as a swamp or marsh. An important difference exists between lowland and highland lakes: lowland lakes are more placid, are less rocky/more sedimentary, have a less sloping bottom, and generally contain more plant life. Large water plants (typically reeds) accelerate this closing process significantly because they trap sediment. Turbid lakes, and lakes with much plant-eating fish, tend to disappear slower. A "disappearing" lake (barely noticeable o ...

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Lake, Lake - Origin of natural lakes, Lake - Characteristics, Lake - Types of lakes, Lake - Artificial lakes, Lake - Abiotic and biotic limnology, Lake - How lakes disappear, Lake - Extraterrestrial lakes, Lake - Notable lakes

Read more here: » Lake: Encyclopedia II - Lake - How lakes disappear

Most lakes are young, as the natural results of erosion will tend to wear away one of the basin sides containing the lake. There are a number of natural processes that can form lakes. A recent tectonic uplift of a mountain range can create bowl-shaped depressions that accumulate water and form lakes. The advance and retreat of glaciers can scrape depressions in the surface where lakes accumulate. Such lake ...

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Lake, Lake - Origin of natural lakes, Lake - Characteristics, Lake - Types of lakes, Lake - Artificial lakes, Lake - Abiotic and biotic limnology, Lake - How lakes disappear, Lake - Extraterrestrial lakes, Lake - Notable lakes

Read more here: » Lake: Encyclopedia II - Lake - Origin of natural lakes

Limnology divides lakes in three zones: littoral zone, which is a sloped area that is close to land; open-water zone, where sunlight is abundant; and deep-water zone, where little sunlight can reach. The depth which light can reach in lakes depends on the density and motion of particles. These particles can be sedimentary or biological in origin and are responsible for the color of the water. Decaying plant matter for instance is responsible for a yellow or brown color, while algae result in greenish water. In very shallow water bodies, iron ...

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Lake, Lake - Origin of natural lakes, Lake - Characteristics, Lake - Types of lakes, Lake - Artificial lakes, Lake - Abiotic and biotic limnology, Lake - How lakes disappear, Lake - Extraterrestrial lakes, Lake - Notable lakes

Read more here: » Lake: Encyclopedia II - Lake - Abiotic and biotic limnology

There are hundreds of coal fires burning around the world.[8] Those burning underground can be difficult to locate and many can not be extinguished. Fires can cause the ground above to subside, combustion gases are dangerous to life, and breaking out to the surface can initiate surface wildfires. Coal seams can be set on fire by spontaneous combustion or contact with a mine fire or surface fire. A grass fire in a coal area can ...

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Coal, Coal - Etymology and folklore, Coal - Composition, Coal - Creation, Coal - Types of coal, Coal - Uses, Coal - Coal as fuel, Coal - Coking and use of coke, Coal - Harmful effects of coal burning, Coal - Coal fires, Coal - World coal reserves

Read more here: » Coal: Encyclopedia II - Coal - Coal fires

Carbon forms more than 50 percent by weight and more than 70 percent by volume of coal (this includes inherent moisture). This is dependant on coal rank, with higher rank coals containing less hydrogen, oxygen and nitrogen, until 95% purity of carbon is achieved at Anthracite rank and above. Graphite formed from coal is the end-product of the thermal and diagenetic conversion of plant matter (50% b ...

See also:

Coal, Coal - Etymology and folklore, Coal - Composition, Coal - Creation, Coal - Types of coal, Coal - Uses, Coal - Coal as fuel, Coal - Coking and use of coke, Coal - Harmful effects of coal burning, Coal - Coal fires, Coal - World coal reserves

Read more here: » Coal: Encyclopedia II - Coal - Composition

Weathering - Carbonation-solution. Carbonation occurs on rocks which contain calcium carbonate such as limestone and chalk. This takes place when rain combines with carbon dioxide or an organic acid to form a weak carbonic acid which reacts with calcium carbonate and forms calcium bicarbonate. The reactions as follows: CO2 + H2O ⇌ H2CO3 carbon dioxide + water ⇌ carbonic acid H2See also:

Weathering, Weathering - Mechanical Physical Weathering, Weathering - Exfoliation, Weathering - Freeze-thaw, Weathering - Pressure release, Weathering - Salt-crystal growth, Weathering - Organic Activity, Weathering - Abrasion, Weathering - Chemical Weathering, Weathering - Carbonation-solution, Weathering - Hydration, Weathering - Hydrolysis, Weathering - Oxidation, Weathering - Acids rain and plants

Read more here: » Weathering: Encyclopedia II - Weathering - Chemical Weathering

Measurements of oxygen isotopes from the GISP2 ice core suggest the ending of the Younger Dryas took place over just 40 - 50 years in three discrete steps, each lasting five years. Other proxy data, such as dust concentration, and snow accumulation, suggest an even more rapid transition, requiring a ~7 °C warming in just a few years [2],[3],[6],[7], [8]. The end of the Younger Dryas has been dated to around 9600 BC (11550 calendar years BP, occurring at 10000 radiocarbon years BP, a "radiocarbon plateau") by a variety of methods, wit ...

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Younger Dryas, Younger Dryas - Abrupt climate change, Younger Dryas - Was the Younger Dryas global?, Younger Dryas - Causes of the Younger Dryas, Younger Dryas - The end of the Younger Dryas, Younger Dryas - The Younger Dryas and the beginning of agriculture

Read more here: » Younger Dryas: Encyclopedia II - Younger Dryas - The end of the Younger Dryas