Топ-100 ★ Free online encyclopedia. Did you know? page 239

★ Free online encyclopedia. Did you know? page 239



                                               

Quartzolite

Quartzolite or silexite is an intrusive igneous rock, in which the mineral quartz is more than 90% of the rocks felsic mineral content, with feldspar at up to 10%. Typically, quartz forms more than 60% of the rock, the rest being mostly feldspar ...

                                               

Iron meteorite

Iron meteorites, also known as siderites, or ferrous meteorites, are a type of meteorites that consist overwhelmingly of an iron–nickel alloy known as meteoric iron that usually consists of two mineral phases: kamacite and taenite. Iron meteorite ...

                                               

CM chondrite

CM chondrites are a group of chondritic meteorites which resemble their type specimen, the Mighei meteorite. The CM is the most commonly recovered group of the carbonaceous chondrite class of meteorites, though all are rarer in collections than o ...

                                               

Carbonaceous chondrite

Carbonaceous chondrites or C chondrites are a class of chondritic meteorites comprising at least 8 known groups and many ungrouped meteorites. They include some of the most primitive known meteorites. The C chondrites represent only a small propo ...

                                               

Enstatite chondrite

Enstatite chondrites are a rare form of meteorite thought to comprise only about 2% of the chondrites that fall on Earth. Only about 200 E-Type chondrites are currently known.

                                               

Mesosiderite

Mesosiderites are a class of stony–iron meteorites consisting of about equal parts of metallic nickel-iron and silicate. They are breccias with an irregular texture, silicates and metal occur often in lumps or pebbles as well as in fine-grained i ...

                                               

Nonmagmatic meteorite

Nonmagmatic meteorite is a deprecated term formerly used in meteoritics to describe iron meteorites that were originally thought to have not formed by igneous processes, to differentiate them from the magmatic meteorites, produced by the crystall ...

                                               

Ordinary chondrite

The ordinary chondrites are a class of stony chondritic meteorites. They are by far the most numerous group and comprise about 87% of all finds. Hence, they have been dubbed "ordinary". The ordinary chondrites are thought to have originated from ...

                                               

Pallasite

It consists of centimeter-sized olivine crystals of peridot quality in an iron-nickel matrix. Coarser metal areas develop Widmanstatten patterns upon etching. Minor constituents are schreibersite, troilite, chromite, pyroxenes, and phosphates.

                                               

Pyroxene pallasite grouplet

The pyroxene pallasite grouplet is a subdivision of the pallasite meteorites. In a grouplet called "pyroxene pallasites", because they are the only pallasites, which contain pyroxene. In the grouplet was proposed in 1995. She currently has only 2 ...

                                               

CI chondrite

CI chondrites, sometimes C1 chondrites, are a group of rare stony meteorites belonging to the carbonaceous chondrites. Samples have been discovered in France, Canada, India, and Tanzania. Compared to all the meteorites found so far, their chemica ...

                                               

H chondrite

The H type ordinary chondrites are the most common type of meteorite, accounting for approximately 40% of all those catalogued, 46% of the ordinary chondrites, and 44% of the chondrites. The ordinary chondrites are thought to have originated from ...

                                               

IIAB meteorites

IIAB meteorites are a group of iron meteorites. Their structural classification ranges from hexahedrites to octahedrites. IIABs have the lowest concentration of nickel of all iron meteorite groups. All iron meteorites are derived from the metalli ...

                                               

IIG meteorite

IIG meteorites are a group of iron meteorites. The group currently has six members. They are hexahedrites with large amounts of schreibersite. The meteoric iron is composed of kamacite.

                                               

IVB meteorite

IVB meteorites are a group of ataxite iron meteorites classified as achondrites. The IVB group has the most extreme chemical compositions of all iron meteorites, meaning that examples of the group are depleted in volatile elements and enriched in ...

                                               

L chondrite

The L type ordinary chondrites are the second most common group of meteorites, accounting for approximately 35% of all those catalogued, and 40% of the ordinary chondrites. The ordinary chondrites are thought to have originated from three parent ...

                                               

LL chondrite

The LL chondrites are a group of stony meteorites, the least abundant group of the ordinary chondrites, accounting for about 10–11% of observed ordinary-chondrite falls and 8–9% of all meteorite falls. The ordinary chondrites are thought to have ...

                                               

Ataxite

Ataxites are a structural class of iron meteorites with a high nickel content and show no Widmanstatten patterns upon etching.

                                               

Hexahedrite

Hexahedrites are a structural class of iron meteorite. They are composed almost exclusively of the nickel–iron alloy kamacite and are lower in nickel content than the octahedrites. The nickel concentration in hexahedrites is always below 5.8% and ...

                                               

Octahedrite

Octahedrites are the most common structural class of iron meteorites. The structures occur because the meteoric iron has a certain nickel concentration that leads to the exsolution of kamacite out of taenite while cooling.

                                               

Stony-iron meteorite

Stony-iron meteorites or siderolites are meteorites that consist of nearly equal parts of meteoric iron and silicates. This distinguishes them from the stony meteorites, that are mostly silicates, and the iron meteorites, that are mostly meteoric ...

                                               

Barkway Chalk Pit

Barkway Chalk Pit is a small nature reserve in Barkway in North Hertfordshire. It was managed by the Herts and Middlesex Wildlife Trust. In February 2016 HMWT announced that three sites, Barkway Chalk Pit, Hill End Pit and Pryors Wood, which HMWT ...

                                               

Grays Thurrock Chalk Pit

Grays Thurrock Chalk Pit is a 17.3 hectare Site of Special Scientific Interest in Grays in Essex. It is part of Chafford Gorges Nature Park, which is managed by the Essex Wildlife Trust. Production of chalk was completed in 1920-ies, and since th ...

                                               

Hill End Pit

Hill End Pit is a 0.7 hectare a nature reserve on the site of a former chalk pit, in St Pauls Walden in North Hertfordshire. It was formerly managed by the Herts and Middlesex Wildlife Trust. In February 2016 HMWT announced that three sites, Bark ...

                                               

Winterbourne Chalk Pit

Winterbourne Chalk Pit is a 0.05-hectare geological Site of Special Scientific Interest west of Winterbourne in Berkshire. It is a Geological Conservation Review site. It is located within the North Wessex Downs. Chalk deposits belong to the late ...

                                               

Aventurine

Aventurine is a form of quartz, characterised by its translucency and the presence of platy mineral inclusions that give a shimmering or glistening effect termed aventurescence. The most common color of aventurine is green, but it can also be ora ...

                                               

Chrome chalcedony

Chrome chalcedony is a green variety of the mineral chalcedony, colored by small quantities of chromium. It is most commonly found in Zimbabwe, where it is known as Mtorolite, Mtorodite, or Matorolite.

                                               

Heliotrope (mineral)

The mineral aggregate heliotrope, also known as bloodstone, is a cryptocrystalline mixture of quartz that occurs mostly as jasper or sometimes as chalcedony. The "classic" bloodstone is opaque green jasper with red inclusions of hematite. Red blo ...

                                               

Jasper

Jasper, an aggregate of microgranular quartz and/or chalcedony and other mineral phases, is an opaque, impure variety of silica, usually red, yellow, brown or green in color, and rarely blue. The common red color is due to iron inclusions. The mi ...

                                               

Biggs jasper

Biggs jasper is a variety of the mineral jasper. It is a "picture jasper" – a jasper that exhibits particular patterns and colors – and is used as an opaque gemstone. It exhibits intricate, shell- or layer-like patterns in shades of brown ranging ...

                                               

Pachycostasaurus

The type species, P. dawni, is represented by a single near complete specimen PETMG R338 which was approximately 3.1 metres in length. It had a robust barrel shaped torso, a relatively short neck and small flippers, indicating that it was not an ...

                                               

Dolmen de Bagneux

The dolmen in Bagneux is probably one of the most majestic French dolmens and the largest of the 4.500 dolmens spread out on about 60 French departments. Although some portal dolmens in Gironde or in Brittany might be a little longer, such as the ...

                                               

La Roche-aux-Fees

La Roche-aux-Fees is a Neolithic gallery grave, or dolmen located in the commune of Esse, in the French department of Ille-et-Vilaine in Brittany. Its name comes from a legend that claims that the stones were placed by fairies. The dolmen consist ...

                                               

Dohnsen-Siddernhausen Dolmen

The dolmen on a low elevation between the villages of Dohnsen and Siddernhausen near the town of Bergen in North Germany, was originally 500 m further north. It was excavated in 1977 and reconstructed in its present location. This dolmen from the ...

                                               

Sieben Steinhauser

The Sieben Steinhauser is a group of five dolmens on the Luneburg Heath in the NATO training area of Bergen-Hohne, in the state of Lower Saxony in northern Germany. The stones are considered to be part of the funnelbeaker culture. The gravesite w ...

                                               

Ballynageeragh Portal Tomb

Dolmens were constructed in Ireland in the 4th millennium BC. Investigations in the late 1930s revealed cremated bone, flint and charcoal in the chamber. The tomb was clumsily reconstructed in 1940.

                                               

Brennanstown Portal Tomb

Brennanstown Portal Tomb, also called Glendruid Dolmen or Cabinteely Dolmen, is a dolmen constructed in Prehistoric Ireland and located in County Dublin. It is a National Monument.

                                               

Brownshill dolmen

Brownshill Dolmen is a very large megalithic portal tomb situated 3 km east of Carlow, in County Carlow, Ireland. Its capstone weighs an estimated 100 metric tons, and is reputed to be the heaviest in Europe. The tomb is listed as a National Monu ...

                                               

Gaulstown Portal Tomb

The Gaulstown Portal Tomb or Gaulstown Dolmen is a megalithic portal tomb situated in Gaulstown, Butlerstown in County Waterford in the Republic of Ireland. It lies about 7 km south west of Waterford City.

                                               

Kilmogue Portal Tomb

Most dolmens were built c. 3000 BC, i.e. in the Neolithic. They may not have been graves, their exact purpose is unknown. The name "Kilmogue" got its name from the Irish Mhog Sill, "the Mogs of the Church", referring to the Celtic deity Mogons, a ...

                                               

Kiltiernan Tomb

The dolmen is sited on a small ledge, close to one of the head waters of the Loughlinstown River on a gentle west-facing slope. The capstone measures 6.5 metres 21 ft in length, 5.3 metres 17 ft in width and 1.55 metres 5.1 ft in depth, weighing ...

                                               

Meehambee Dolmen

The Meehambee Dolmen is a megalithic portal tomb dating from about 3500 BC located in County Roscommon, Ireland. He was discovered by two local children in the 1960-ies, which found two stone axes. Originally supported on 6 upright portals, 2.3 m ...

                                               

Poulnabrone dolmen

Poulnabrone dolmen is an unusually large dolmen or portal tomb located in the Burren, County Clare, Ireland. Situated on one of the most desolate and highest points of the region, it comprises three standing portal stones supporting a heavy horiz ...

                                               

Proleek Dolmen

The dolmen dates to the Neolithic, around 3000 BC. It was used for interments in which the cremated remains were placed in the tomb, often accompanied by grave goods, including tools, beads and pottery. The tomb may be aligned so that its portal ...

                                               

Beenalaght

Beenalaght is an alignment of six standing stones located on a flat pasture in Reanthesure, 0.5km west of the village of Bweeng, County Cork, Ireland. It is 13.6km south-west of Mallow, on a hill to the west of the Mallow-Coachford Road. Beenalag ...

                                               

Carricknagat Megalithic Tombs

Carricknagat tombs were built c. 4000–2500 BC, in the Neolithic. The name means "cat stone" or "stone marten," ancient monuments often say that it is home to wild animals, perhaps representing spirits of the dead.

                                               

Carrigaphooca Stone Circle

Carrigaphooca Stone Circle is situated 4.4 km 2.7 mi west of Macroom, immediately east of Carrigaphooca Castle, north of the N22, and near the confluence of the River Sullane and River Foherish.

                                               

Clodagh Standing Stones

The stones probably date to the Bronze Age period. The purpose of standing stones is unclear, they may have served as boundary markers, ritual or ceremonial sites, burial sites or astrological alignment.

                                               

Coolcoulaghta Standing Stones

The stones probably date to the Bronze Age period. It points towards Dunbeacon stone circle 400 m ¼ mile to the west and the stones may have been used for astronomical observation. They were removed in 1980, but the stones were replaced in 1983 b ...

                                               

Craigs Dolmen

Craigs Dolmen is situated three miles north of Rasharkin, County Antrim, Northern Ireland, close to a minor road, at a height of 200m on the Long Mountain. Craigs Dolmen passage tomb is a State Care Historic Monument in the townland of Craigs, in ...

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Pino - logical board game which is based on tactics and strategy. In general this is a remix of chess, checkers and corners. The game develops imagination, concentration, teaches how to solve tasks, plan their own actions and of course to think logically. It does not matter how much pieces you have, the main thing is how they are placement!

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