Vale of Kent

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The Vale of Kent, located in Kent, England, is the name given to the broad clay vale between the Greensand Ridge and the High Weald. The area is drained by a number of rivers, including the Beult, Eden, Medway, Stour and River Teise. [1]

Principal settlements in the Vale include Ashford and Tonbridge.

Geology

Geology of south-eastern England. The High Weald is in lime green (9a); the Low Weald, darker green (9). Chalk Downs, pale green (6) S East Geology.jpg
Geology of south-eastern England. The High Weald is in lime green (9a); the Low Weald, darker green (9). Chalk Downs, pale green (6)
Geological section from north to south: High and Low Weald shown as one KentGeologyWealdenDomeSimple.svg
Geological section from north to south: High and Low Weald shown as one

The Weald is the eroded remains of a geological structure, an anticline, a dome of layered Lower Cretaceous rocks cut through by erosion to expose the layers as sandstone ridges and clay valleys. The oldest rocks exposed at the centre of the anticline are correlated with the Purbeck Beds of the Upper Jurassic. Above these, the Cretaceous rocks, include the Wealden Group of alternating sands and clays - the Ashdown Sand, Wadhurst Clay, Tunbridge Wells Sand (collectively known as the Hastings Beds) and the Weald Clay. The Wealden Group is overlain by the Lower Greensand and the Gault Formation, consisting of the Gault Clay and the Upper Greensand. [2]

The rocks of the central part of the anticline include hard sandstones, and these form hills now called the High Weald. The peripheral areas are mostly of softer sandstones and clays and these form the gentler rolling landscape of Low Weald, of which the Vale of Kent is a part. [1] The Weald-Artois Anticline continues some 65 km (40 mi) further south-eastwards under the Straits of Dover, and includes the Boulonnais of France.

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The Weald is an area of South East England between the parallel chalk escarpments of the North and the South Downs. It crosses the counties of Hampshire, Surrey, Sussex and Kent. It has three separate parts: the sandstone "High Weald" in the centre; the clay "Low Weald" periphery; and the Greensand Ridge, which stretches around the north and west of the Weald and includes its highest points. The Weald once was covered with forest, and its name, Old English in origin, signifies "woodland". The term is still used today, as scattered farms and villages sometimes refer to the Weald in their names.

Greensand

Greensand or green sand is a sand or sandstone which has a greenish color. This term is specifically applied to shallow marine sediment that contains noticeable quantities of rounded greenish grains. These grains are called glauconies and consist of a mixture of mixed-layer clay minerals, such as smectite and glauconite mica. Greensand is also loosely applied to any glauconitic sediment.

Gault

The Gault Formation is a geological formation of stiff blue clay deposited in a calm, fairly deep-water marine environment during the Lower Cretaceous Period. It is well exposed in the coastal cliffs at Copt Point in Folkestone, Kent, England, where it overlays the Lower Greensand formation, and underlies the Upper Greensand Formation. These represent different facies, with the sandier parts probably being deposited close to the shore and the clay in quieter water further from the source of sediment; both are believed to be shallow-water deposits.

<span class="mw-page-title-main">Geology of Dorset</span> Geological overview of the English county of Dorset

Dorset is a county in South West England on the English Channel coast. Covering an area of 2,653 square kilometres (1,024 sq mi); it borders Devon to the west, Somerset to the north-west, Wiltshire to the north-east, and Hampshire to the east. The great variation in its landscape owes much to the underlying geology, which includes an almost unbroken sequence of rocks from 200 to 40 million years ago (Mya) and superficial deposits from 2 Mya to the present. In general, the oldest rocks appear in the far west of the county, with the most recent (Eocene) in the far east. Jurassic rocks also underlie the Blackmore Vale and comprise much of the coastal cliff in the west and south of the county; although younger Cretaceous rocks crown some of the highpoints in the west, they are mainly to be found in the centre and east of the county.

Wealden Group

The Wealden Group, occasionally also referred to as the Wealden Supergroup, is a group in the lithostratigraphy of southern England. The Wealden group consists of paralic to continental (freshwater) facies sedimentary rocks of Berriasian to Aptian age and thus forms part of the English Lower Cretaceous. It is composed of alternating sands and clays. The sandy units were deposited in a flood plain of braided rivers, the clays mostly in a lagoonal coastal plain.

<span class="mw-page-title-main">Greensand Ridge</span> Range of hills in south east England, UK

The Greensand Ridge, also known as the Wealden Greensand is an extensive, prominent, often wooded, mixed greensand/sandstone escarpment in south-east England. Forming part of the Weald, a former dense forest in Sussex, Surrey and Kent, it runs to and from the East Sussex coast, wrapping around the High Weald and Low Weald. It reaches its highest elevation, 294 metres (965 ft), at Leith Hill in Surrey—the second highest point in south-east England, while another hill in its range, Blackdown, is the highest point in Sussex at 280 metres (919 ft). The eastern end of the ridge forms the northern boundary of Romney Marsh.

Geography of Kent Overview of the geography of Kent

Kent is the south-easternmost county in England. It is bounded on the north by the River Thames and the North Sea, and on the south by the Straits of Dover and the English Channel. The continent of Europe is 21 miles across the straits.

Weald–Artois Anticline Geologic structure in southern England and northern France

The Weald–Artois Anticline, or Wealden Anticline, is a large anticline, a geological structure running between the regions of the Weald in southern England and Artois in northern France. The fold formed during the Alpine orogeny, from the late Oligocene to middle Miocene as an uplifted form of the Weald basin through inversion of the basin. The folding resulted in uplift of about 180 metres (590 ft), though concurrent erosion may have substantially reduced the actual height of the resulting chalk ridges.

London Basin

The London Basin is an elongated, roughly triangular sedimentary basin approximately 250 kilometres (160 mi) 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.

Vale of Holmesdale

Holmesdale, also known as the Vale of Holmesdale, is a valley in South-East England that falls between the hill ranges of the North Downs and the Greensand Ridge of the Weald, in the counties of Kent and Surrey. It stretches from Folkestone on the Kent coast, through Ashford, Harrietsham, Maidstone, Riverhead/Sevenoaks, Westerham, Oxted, Godstone, Redhill, Reigate, Dorking, Gomshall, and Guildford – west of which it is also called by the local name of "Puttenham Vale" – as it continues through the village of Puttenham, to the market town of Farnham.

Geography of Sussex Overview of the geography of Sussex

Sussex is a historic county and cultural region in the south of England corresponding roughly in area to the ancient Kingdom of Sussex. It is bounded on the north by Surrey, north-east by Kent, south by the English Channel, and west by Hampshire, and is divided for local government into West Sussex and East Sussex and the city of Brighton and Hove. The city of Brighton & Hove was created a unitary authority in 1997, and was granted City status in 2000. Until then Chichester had been Sussex's only city. By convention, Chichester is Sussex's capital city and Lewes is Sussex's county town.

Lower Greensand Group Geological unit

The Lower Greensand Group is a geological unit present across large areas of Southern England. It was deposited during the Aptian and Albian stages of the Early Cretaceous. It predominantly consists of sandstone and unconsolidated sand that were deposited in shallow marine conditions.

Geology of East Sussex Overview of the geology of East Sussex

The geology of East Sussex is defined by the Weald–Artois anticline, a 60 kilometres (37 mi) wide and 100 kilometres (62 mi) long fold within which caused the arching up of the chalk into a broad dome within the middle Miocene, which has subsequently been eroded to reveal a lower Cretaceous to Upper Jurassic stratigraphy. East Sussex is best known geologically for the identification of the first dinosaur by Gideon Mantell, near Cuckfield, to the famous hoax of the Piltdown man near Uckfield.

Tunbridge Wells Sand Formation

The Tunbridge Wells Sand Formation is a geological unit which forms part of the Wealden Group and the uppermost and youngest part of the unofficial Hastings Beds. These geological units make up the core of the geology of the Weald in the English counties of West Sussex, East Sussex and Kent.

Wadhurst Clay Formation

The Wadhurst Clay Formation is a geological unit which forms part of the Wealden Group and the middle part of the now unofficial Hastings Beds. These geological units make up the core of the geology of the High Weald in the English counties of West Sussex, East Sussex and Kent.

Geology of the Isle of Wight

The geology of the Isle of Wight is dominated by sedimentary rocks of Cretaceous and Paleogene age. This sequence was affected by the late stages of the Alpine Orogeny, forming the Isle of Wight monocline, the cause of the steeply-dipping outcrops of the Chalk Group and overlying Paleogene strata seen at The Needles, Alum Bay and Whitecliff Bay.

The geology of Kent in southeast England largely consists of a succession of northward dipping late Mesozoic and Cenozoic sedimentary rocks overlain by a suite of unconsolidated deposits of more recent origin.

The geology of West Sussex in southeast England comprises a succession of sedimentary rocks of Cretaceous age overlain in the south by sediments of Palaeogene age. The sequence of strata from both periods consists of a variety of sandstones, mudstones, siltstones and limestones. These sediments were deposited within the Hampshire and Weald basins. Erosion subsequent to large scale but gentle folding associated with the Alpine Orogeny has resulted in the present outcrop pattern across the county, dominated by the north facing chalk scarp of the South Downs. The bedrock is overlain by a suite of Quaternary deposits of varied origin. Parts of both the bedrock and these superficial deposits have been worked for a variety of minerals for use in construction, industry and agriculture.

Geology of Surrey

The geology of Surrey is dominated by sedimentary strata from the Cretaceous, overlaid by clay and superficial deposits from the Cenozoic.

The geology of the South Downs National Park in South East England comprises a gently folded succession of sedimentary rocks from the Cretaceous and early Palaeogene periods overlain in places by a range of superficial deposits from the last 2.6 million years. Whereas the South Downs are formed from the Late Cretaceous age chalk, the South Downs National Park extends into the Weald to the north of the range and thereby includes older rock strata dating from the Early Cretaceous including sandstones and mudstones. The youngest solid rocks are found on the southern fringes of the National Park in the eastern extension of the Hampshire Basin and include sand, silt and clay deposited during the Palaeocene and Eocene epochs.

References

  1. 1 2 John Taylor. "Kent Geology". Kgg.org.uk. Retrieved 8 May 2016.
  2. Gallois R.W. & Edmunds M.A. (4th Ed 1965), The Wealden District, British Regional Geology series, British Geological Survey, ISBN   0-11-884078-9

Coordinates: 51°12′09″N0°31′04″E / 51.2024°N 0.5177°E / 51.2024; 0.5177