The Winchester-King's Somborne Syncline is one of a series of parallel east-west trending folds in the Cretaceous chalk of Hampshire. It lies at the western end of the South Downs, immediately to the north of the Winchester-East Meon Anticline and east of Salisbury Plain.
In structural geology, geological fold occurs when one or a stack of originally flat and planar surfaces, such as sedimentary strata, are bent or curved as a result of permanent deformation. Synsedimentary folds are those due to slumping of sedimentary material before it is lithified. Folds in rocks vary in size from microscopic crinkles to mountain-sized folds. They occur singly as isolated folds and in extensive fold trains of different sizes, on a variety of scales.
The Cretaceous is a geologic period and system that spans 79 million years from the end of the Jurassic Period 145 million years ago (mya) to the beginning of the Paleogene Period 66 mya. It is the last period of the Mesozoic Era, and the longest period of the Phanerozoic Eon. The Cretaceous Period is usually abbreviated K, for its German translation Kreide.
Chalk is a soft, white, porous, sedimentary carbonate rock, a form of limestone composed of the mineral calcite. Calcite is an ionic salt called calcium carbonate or CaCO3. It forms under reasonably deep marine conditions from the gradual accumulation of minute calcite shells (coccoliths) shed from micro-organisms called coccolithophores. Flint (a type of chert) is very common as bands parallel to the bedding or as nodules embedded in chalk. It is probably derived from sponge spicules or other siliceous organisms as water is expelled upwards during compaction. Flint is often deposited around larger fossils such as Echinoidea which may be silicified (i.e. replaced molecule by molecule by flint).
The fold axis runs for around 40 kilometres (25 mi) from north of East Tytherley in the west, between Winchester and Kings Worthy, towards Four Marks in the east. [1] [2] To the north-east of Winchester the fold axis is followed by the valley of the River Itchen, which turns abruptly south to cut across the structure and the Winchester-East Meon Anticline to the south.
East Tytherley is a small village in Hampshire, England.
Winchester is a city and the county town of Hampshire, England. The city lies at the heart of the wider City of Winchester, a local government district, and is located at the western end of the South Downs National Park, along the course of the River Itchen. It is situated 60 miles (97 km) south-west of London and 13.6 miles (21.9 km) from Southampton, its closest city. At the time of the 2011 Census, Winchester had a population of 45,184. The wider City of Winchester district which includes towns such as Alresford and Bishop's Waltham has a population of 116,800.
Kings Worthy is a village and civil parish in Hampshire, England, approximately two miles north-east of Winchester. Kings Worthy was a tithing of Barton Stacey when the Domesday Book was written.
Parallel folds to the north include the Stockbridge Anticline and the Micheldever Syncline. To the south-west across the River Test is the similar Alderbury-Mottisfont Syncline. As with other nearby folds, the structure is controlled by movement of fault blocks within the Jurassic strata below. [3]
The Stockbridge Anticline is one of a series of parallel east-west trending folds in the Cretaceous chalk of Hampshire. It lies at the western end of the South Downs, immediately to the north of the Winchester-King's Somborne Syncline and east of Salisbury Plain.
The Micheldever Syncline is one of a series of parallel east-west trending folds in the Cretaceous chalk of Hampshire. It lies at the western end of the South Downs, immediately to the north of the Stockbridge Anticline and east of Salisbury Plain.
The River Test is a river in Hampshire, England. It has a total length of 40 miles (64 km) and it flows through downland from its source near Ashe to its estuary at Southampton, where it converges with the River Itchen to form Southampton Water. In its upper reaches it is a chalk stream, and is used for fly fishing for trout.
The geology of Hampshire in southern England broadly comprises a gently folded succession of sedimentary rocks dating from the Cretaceous and Palaeogene periods. The lower (early) Cretaceous rocks are sandstones and mudstones whilst those of the upper (late) Cretaceous are the various formations which comprise the Chalk Group and give rise to the county's downlands. Overlying these rocks are the less consolidated Palaeogene clays, sands, gravels and silts of the Lambeth, Thames and Bracklesham Groups which characterise the Hampshire Basin.
In structural geology, an anticline is a type of fold that is an arch-like shape and has its oldest beds at its core. A typical anticline is convex up in which the hinge or crest is the location where the curvature is greatest, and the limbs are the sides of the fold that dip away from the hinge. Anticlines can be recognized and differentiated from antiforms by a sequence of rock layers that become progressively older toward the center of the fold. Therefore, if age relationships between various rock strata are unknown, the term antiform should be used.
Twyford is a village and civil parish in Hampshire, England, approximately three miles south of Winchester and near the M3 motorway and Twyford Down. In 2001, the population of the parish was 1,456. The village and parish are on the left bank of the Itchen, which passes through nearby watermeadows, and has been important economically for its residents.
Beacon Hill, Warnford, Hampshire is a chalk hill in the South Downs on the boundary of the parishes of Warnford and Exton. Part of the hill is a national nature reserve and 44.8 hectares biological SSSI, first notified in 1979.
Chilcomb is a small village and civil parish in the English county of Hampshire 3 miles (4.8 km) east of Winchester and includes the South Downs Way long distance footpath.
Upham is a small village and civil parish in the south of England located in Hampshire approximately 7 miles south-east of Winchester.
St. Catherine's Hill is a small but dramatic chalk hill to the south east of Winchester in Hampshire, England. Rising steeply some 67 metres (220 ft) from the water meadows of the River Itchen, the summit of the hill at 97 metres (318 ft) provides a fine view over Winchester.
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.
The Hampshire Basin is a geological basin of Palaeogene age in southern England, underlying parts of Hampshire, the Isle of Wight, Dorset, and Sussex. Like the London Basin to the northeast, it is filled with sands and clays of Paleocene and younger ages and it is surrounded by a broken rim of chalk hills of Cretaceous age.
The Dent Fault is a major fault zone on the boundary between the counties of Cumbria and North Yorkshire in northern England. It is named after the village of Dent in Dentdale, on the western margin of the Yorkshire Dales.
Henwood Down is one of the highest points in the county of Hampshire, England, and in the South Downs, reaching a height of 201 metres (659 ft) above sea level. Its prominence of 64 metres qualifies it as a Tump.
The Winchester-East Meon Anticline is one of a series of parallel east-west trending folds in the Cretaceous chalk of Hampshire. It lies at the western end of the South Downs, immediately to the north of the Hampshire Basin and south-east of Salisbury Plain.
The Dean Hill Anticline is an east-west trending fold in the Cretaceous chalk of Hampshire. It lies immediately to the north of the Hampshire Basin and south of Salisbury Plain.
The Alderbury-Mottisfont Syncline is an east-west trending fold in the Cretaceous chalk of Hampshire. It lies to the north of the Dean Hill Anticline and south of Salisbury Plain.
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.
The Portsdown Anticline is a north-facing geological fold of Tertiary age affecting rocks in Hampshire, southern England. This upfold of the local sedimentary rock sequence is paralleled by the Bere Forest/Chichester Syncline (downfold) about 2km to its north and a postulated deep fault to the north again. Further west, this major east-west structure adopts more of a NW - SE alignment. At the surface the Portsdown Anticline is seen to affect the Chalk rocks of Late Cretaceous age at Ports Down though it is known to also affect the underlying Jurassic strata.
The Exmoor Group is a late Devonian to early Carboniferous lithostratigraphic group in southwest England whose outcrop extends from Croyde in north Devon east across Exmoor to Minehead in west Somerset. The group comprises the following formations the:
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