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River Bulbourne
The River Bulbourne is a small river in Dacorum, Hertfordshire, England. The word bourne derives from the Anglo-Saxon word for a stream. It is an unnavigable tributary of the River Gade, which flows into the River Colne, which in turn is a tributary of the River Thames. The Bulbourne is an example of a chalk stream, which is a watercourse that flows from chalk-fed groundwater. Chalk streams are a very rare habitat globally, with more than 85% of all the 210 chalk streams in the world are found in England. The river is reduced in size, due to human activity, the main one being the building of the London to Birmingham Grand Union Canal through the narrow valley which takes most of the river's water. Geography The Bulbourne flows in the Chiltern Hills, part of a system of chalk downlands throughout eastern and southern England, which formed between 84 and 100 million years ago in the Cretaceous Period when the area was a chalk-depositing marine environment. The valley is at the sou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grand Union Canal
The Grand Union Canal in England is part of the British canal system. It is the principal navigable waterway between London and the Midlands. Starting in London, one arm runs to Leicester and another ends in Birmingham, with the latter stretching for with 166 locks from London. The Birmingham line has a number of short branches to places including Slough, Aylesbury, Wendover, and Northampton. The Leicester line has two short arms of its own, to Market Harborough and Welford. It has links with other canals and navigable waterways, including the River Thames, the Regent's Canal, the River Nene and River Soar, the Oxford Canal, the Stratford-upon-Avon Canal, the Digbeth Branch Canal and the Birmingham and Fazeley Canal. The canal south of Braunston to the River Thames at Brentford in London is the original Grand Junction Canal. At Braunston the latter met the Oxford Canal linking back to the Thames to the south and to Coventry to the north via the Coventry Canal. "Grand ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chalk Streams
Chalk streams are rivers that rise from springs in landscapes with chalk bedrock. Since chalk is permeable, water percolates easily through the ground to the water table and chalk streams therefore receive little surface runoff. As a result, the water in the streams contains little organic matter and sediment and is generally very clear. The beds of the rivers are generally composed of clean, compacted gravel and flints, which are good spawning areas for Salmonidae fish species. Since they are fed primarily by aquifers, the flow rate, mineral content and temperature range of chalk streams exhibit less seasonal variation than other rivers. They are mildly alkaline and contain high levels of nitrate, phosphate, potassium and silicate. In addition to algae and diatoms, the streams provide a suitable habitat for macrophytes (including water crowfoot) and oxygen levels are generally supportive of coarse fish populations. Of the 210 rivers classified as chalk streams glob ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boxmoor
Boxmoor is part of Hemel Hempstead in Hertfordshire. It is within the district of Dacorum and comprises mainly 19th-century housing and meadowland, with transport links from London to the Midlands. At the 2011 Census, the population of Boxmoor was included in the Dacorum ward of Bovingdon, Flaunden and Chipperfield. History The name Boxmoor derives from the box tree, a bushy inhabitant of the chalky hills that surround the location. This is linked together with the word 'mor', which signifies a marshy spot; Boxmoor's ancient watermeadows are still a major feature of the locality. A mesolithic camp site was discovered in 1975 on the site of what is now Boxmoor trout fishery, close to Fisheries wharf. Finds include 'pot boiler' stones, bones of the wild ox, Bos Primigenius and a hand-crafted grinding quern made of the hard local rock known as Hertfordshire puddingstone. All were dated to around 1500 BCE. An even older stone axe head dated to 6000 BCE was also discovered. The rem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bourne End, Hertfordshire
Bourne End is a village in Hertfordshire, England. It is situated on the ancient Roman Akeman Street between Berkhamsted and Hemel Hempstead, on the former A41 London-Liverpool Trunk Route, on the Grand Union Canal that runs between London and Birmingham and at the confluence of the Chiltern chalk stream, the Bourne Gutter and the River Bulbourne. It is in the Dacorum Ward of Bovingdon, Flaunden and Chipperfield. History Bourne End formerly lay within the extended parish of Northchurch (Berkhamsted St. Mary). It was then known as the hamlet of Broadway. In 1909 the south-eastern part of Northchurch was separated into a new parish consisting of the hamlets of Sunnyside and Broadway. Bourne End/Broadway became a separate parish in 1915. Bourne End derives its name as it lies at the end of the Bourne Gutter, an irregularly flowing stream, at its confluence with the River Bulbourne. According to local tradition the Bourne Gutter is a Woe Water that only flows at times of tragedy. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Berkhamsted
Berkhamsted ( ) is a historic market town in Hertfordshire, England, in the Bulbourne valley, north-west of London. The town is a civil parish with a town council within the borough of Dacorum which is based in the neighbouring large new town of Hemel Hempstead. Berkhamsted, along with the adjoining village of Northchurch, is encircled by countryside, much of it in the Chiltern Hills which is an Area of Outstanding Natural Beauty (AONB). The High Street is on a pre-Roman route known by its Saxon name: Akeman Street. The earliest written reference to Berkhamsted was in 970. The settlement was recorded as a ''Burbium'' (ancient borough) in the Domesday Book in 1086. The most notable event in the town's history occurred in December 1066. After William the Conqueror defeated King Harold's Anglo-Saxon army at the Battle of Hastings, the Anglo-Saxon leadership surrendered to the Norman encampment at Berkhamsted. The event was recorded in the Anglo-Saxon Chronicle. From 1066 to 149 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alluvium
Alluvium (from Latin ''alluvius'', from ''alluere'' 'to wash against') is loose clay, silt, sand, or gravel that has been deposited by running water in a stream bed, on a floodplain, in an alluvial fan or beach, or in similar settings. Alluvium is also sometimes called alluvial deposit. Alluvium is typically geologically young and is not consolidated into solid rock. Sediments deposited underwater, in seas, estuaries, lakes, or ponds, are not described as alluvium. Floodplain alluvium can be highly fertile, and supported some of the earliest human civilizations. Definitions The present consensus is that "alluvium" refers to loose sediments of all types deposited by running water in floodplains or in alluvial fans or related landforms. However, the meaning of the term has varied considerably since it was first defined in the French dictionary of Antoine Furetière, posthumously published in 1690. Drawing upon concepts from Roman law, Furetière defined ''alluvion'' (the F ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
London Basin
The London Basin is an elongated, roughly triangular sedimentary basin approximately long which underlies London and a large area of south east England, south eastern East Anglia and the adjacent North Sea. The basin formed as a result of compressional tectonics related to the Alpine orogeny during the Palaeogene period and was mainly active between 40 and 60 million years ago. Boundaries and shape Spatial boundaries The generally accepted boundaries are the Late Cretaceous Chalk Group's escarpments of the Chilterns and Marlborough Downs to the north and the North Downs and Berkshire Downs to the south. To the south lie the Weald and Salisbury Plain and to the north is the Vale of Aylesbury. The approximate western limit is in the Marlborough area of Wiltshire. The eastern end merges with the North Sea Basin, extending on land along the north Kent coast to Reculver and up the east coast of Essex and into Suffolk, where it is overlain by Pleistocene 'Crag' deposits which cover ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Syncline
In structural geology, a syncline is a fold with younger layers closer to the center of the structure, whereas an anticline is the inverse of a syncline. A synclinorium (plural synclinoriums or synclinoria) is a large syncline with superimposed smaller folds. Synclines are typically a downward fold (synform), termed a synformal syncline (i.e. a trough), but synclines that point upwards can be found when strata have been overturned and folded (an antiformal syncline). Characteristics On a geologic map, synclines are recognized as a sequence of rock layers, with the youngest at the fold's center or ''hinge'' and with a reverse sequence of the same rock layers on the opposite side of the hinge. If the fold pattern is circular or elongate, the structure is a basin. Folds typically form during crustal deformation as the result of compression that accompanies orogenic mountain building. Notable examples * Powder River Basin, Wyoming, US * Sideling Hill roadcut along Interstate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chalk Group
The Chalk Group (often just called the Chalk) is the lithostratigraphic unit (a certain number of rock strata) which contains the Upper Cretaceous limestone succession in southern and eastern England. The same or similar rock sequences occur across the wider northwest European chalk 'province'. It is characterised by thick deposits of chalk, a soft porous white limestone, deposited in a marine environment. Chalk is a limestone that consists of coccolith biomicrite. A biomicrite is a limestone composed of fossil debris ("bio") and calcium carbonate mud ("micrite"). Most of the fossil debris in chalk consists of the microscopic plates, which are called coccoliths, of microscopic green algae known as coccolithophores. In addition to the coccoliths, the fossil debris includes a variable, but minor, percentage of the fragments of foraminifera, ostracods and mollusks. The coccolithophores lived in the upper part of the water column. When they died, the microscopic calcium carbonate p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cretaceous Period
The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of the entire Phanerozoic. The name is derived from the Latin ''creta'', "chalk", which is abundant in the latter half of the period. It is usually abbreviated K, for its German translation ''Kreide''. The Cretaceous was a period with a relatively warm climate, resulting in high eustatic sea levels that created numerous shallow inland seas. These oceans and seas were populated with now-extinct marine reptiles, ammonites, and rudists, while dinosaurs continued to dominate on land. The world was ice free, and forests extended to the poles. During this time, new groups of mammals and birds appeared. During the Early Cretaceous, flowering plants appeared and began to rapidly diversify, becoming the dominant group of plants across the Earth by t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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