The Bytham River is said to have been one of the great Pleistocene rivers of central and eastern England until it was destroyed by the advancing ice sheets of the Anglian Glaciation around 450,000 years ago. The river is named after Castle Bytham in Lincolnshire, where the watercourse is said to have crossed the Lincolnshire limestone hills in a valley now buried by Anglian till. West of that location, its catchment area included much of Warwickshire, Leicestershire and Derbyshire. East of that location, the Bytham flowed across what is now the Fen Basin to Shouldham, then southward to Mildenhall, then eastward across East Anglia. It met the Proto-Thames in a delta near what is now the Norfolk/Suffolk border and flowed into the North Sea. Britain was then joined to the Continent by a land bridge and the Bytham joined the North Sea somewhere beyond the northern end of that land bridge. [1] [2] [3]
Chris Stringer writes: "As the Bytham River slowed past Warren Hill [in Norfolk] towards its delta on what is now the East Anglian coast, it deposited sediments on the edge of the huge north-facing bay, into which the Rhine also flowed. The sites of Norton Subcourse in Norfolk and nearby Pakefield, just over the border in Suffolk, were probably both related to the Bytham, and they record a time when the climate of Britain was balmy and Mediterranean, and this part of East Anglia was a fertile estuarine plain." [4]
The Anglian ice advance which followed, with its ice front reaching at least as far south as London and Birmingham, overrode all or most of the Bytham's catchment area. The course of the river was severed in the region of the Fen Basin. Following the ice retreat, the Bytham's remaining western section became part of the Trent catchment, and its remaining eastern section became a precursor of the Waveney river, running across East Anglia. [5]
In the mid-2010s the existence of the Bytham was disputed. It was argued that an eastern section of the supposed river, flowing across central East Anglia, was indeed part of a pre-Anglian watercourse, but one which came from the north-west, through the Ancaster Gap in Lincolnshire. That "proto-Trent" river was severely disrupted by the Anglian glaciation. It has further been suggested that a western section of the supposed "Bytham river" was part of a post-Anglian watercourse which flowed SW-NE from Warwickshire to the North Sea via The Wash. That "proto-Soar" river was also modified by glaciation, but in that case by the later Wolstonian ice advance. Those western and eastern sections never linked up to form a "Bytham river". [6] [7]
Another study asserted that the refutation of the existence of the Bytham is itself "contradicted by an abundance of evidence", and that sand and gravel deposits of the proto-Soar in Leicestershire could "only have been emplaced by a river flowing eastward across East Anglia" (ie, according to this study, by a large, pre-Anglian river, the Bytham). [8] [9]
The Anglian Stage is the name used in the British Isles for a middle Pleistocene glaciation. It precedes the Hoxnian Stage and follows the Cromerian Stage in the British Isles. The Anglian Stage is correlated to Marine Isotope Stage 12, which started about 478,000 years ago and ended about 424,000 years ago.
The Hoxnian Stage was a middle Pleistocene stage of the geological history of the British Isles. It was an interglacial which preceded the Wolstonian Stage and followed the Anglian Stage. It is equivalent to Marine Isotope Stage 11. Marine Isotope Stage 11 started 424,000 years ago and ended 374,000 years ago. The Hoxnian is divided into sub-stages Ho I to Ho IV.
The Wolstonian Stage is a middle Pleistocene stage of the geological history of Earth from approximately 374,000 until 130,000 years ago. It precedes the Eemian Stage in Europe and follows the Hoxnian Stage in the British Isles.
The Illinoian Stage is the name used by Quaternary geologists in North America to designate the period c.191,000 to c.130,000 years ago, during the Chibanian stage of the Pleistocene, when sediments comprising the Illinoian Glacial Lobe were deposited. It precedes the Sangamonian Stage and follows the Pre-Illinoian Stage in North America. The Illinoian Stage is defined as the period of geologic time during which the glacial tills and outwash, which comprise the bulk of the Glasford Formation, accumulated to create the Illinoian Glacial Lobe. It occurs at about the same time as the penultimate glacial period.
The Bramertonian Stage is the name for an early Pleistocene biostratigraphic stage in the British Isles. It precedes the Pre-Pastonian Stage. It derives its name from Bramerton Pits in Norfolk, where the deposits can be found on the surface. The exact timing of the beginning and end of the Bramertonian Stage is currently unknown. It is only known that it is equivalent to the Tiglian C1-4b Stage of Europe and early Pre-Illinoian Stage of North America. It lies somewhere in time between Marine Oxygen Isotope stages 65 to 95 and somewhere between 1.816 and 2.427 Ma. The Bramertonian is correlated with the Antian stage identified from pollen assemblages in the Ludham borehole.
The Corton Formation is a series of deposits of Middle Pleistocene age found primarily along the coasts of Suffolk and Norfolk in eastern England.
The Ancestral Thames is the geologically ancient precursor to the present day River Thames. The river has its origins in the emergence of Britain from a Cretaceous sea over 60 million years ago. Parts of the river's course were profoundly modified by the Anglian glaciation some 450,000 years ago. The extensive terrace deposits laid down by the Ancestral Thames over the past two million years or so have provided a rich source of material for studies in geology, geomorphology, palaeontology and archaeology.
Lake Harrison or Lake Bosworth is the name given to a lake that in parts of the Ice Age may have covered much of the Midlands in England around Warwick, Birmingham and Leicester. It is suggested that it was formed when ice sheets over Wales and Northern England blocked drainage north-eastwards, trapping a lake between this and the Cotswolds. Finally the lake made two overflow courses, until drainage by the Cole and Soar could resume due to glacial retreat:
The Lea Valley, the valley of the River Lea, has been used as a transport corridor, a source of sand and gravel, an industrial area, a water supply for London, and a recreational area. The London 2012 Summer Olympics were based in Stratford, in the Lower Lea Valley. It is important for London's water supply, as the source of the water transported by the New River aqueduct, but also as the location for the Lee Valley Reservoir Chain, stretching from Enfield through Tottenham and Walthamstow.
Turkey Brook is a river in the northern outskirts of London. It rises in Potters Bar, Hertfordshire, and flows broadly eastwards to merge with the River Lea Navigation near Enfield Lock.
Pymmes Brook is located in North London and named after William Pymme, a local land owner. It is a minor tributary of the River Lea. The brook mostly flows through urban areas and is particularly prone to flooding in its lower reaches. To alleviate the problem the brook has been culverted in many areas. Part of it is a Site of Borough Importance for Nature Conservation, Grade II.
Salmons Brook is a minor tributary of the River Lea, located in the London Borough of Enfield.
Cuffley Brook is a tributary of Turkey Brook. It runs through parts of Hertfordshire and the London Borough of Enfield, England. After the confluence of the two streams in Whitewebbs Park, the watercourse continues eastwards as Turkey Brook to join the River Lea near Enfield Lock.
The Pre-Illinoian Stage is used by Quaternary geologists for the early and middle Pleistocene glacial and interglacial periods of geologic time in North America from ~2.5–0.2 Ma.
The Norwich Crag Formation is a stratigraphic unit of the British Pleistocene Epoch. It is the second youngest unit of the Crag Group, a sequence of four geological formations spanning the Pliocene to Lower Pleistocene transition in East Anglia. It was deposited between approximately 2.4 and 1.8 million years ago, during the Gelasian Stage.
The geology of Norfolk in eastern England largely consists of late Mesozoic and Cenozoic sedimentary rocks of marine origin covered by an extensive spread of unconsolidated recent deposits.
The Crag Group is a geological group outcropping in East Anglia, UK and adjacent areas of the North Sea. Its age ranges from approximately 4.4 to 0.478 million years BP, spanning the late Pliocene and early to middle Pleistocene epochs. It comprises a range of marine and estuarine sands, gravels, silts and clays deposited in a relatively shallow-water, tidally-dominated marine embayment on the western margins of the North Sea basin. The sands are characteristically dark green from glauconite but weather bright orange, with haematite 'iron pans' forming. The lithology of the lower part of the Group is almost entirely flint. The highest formation in the Group, the Wroxham Crag, contains over 10% of far-travelled lithologies, notably quartzite and vein quartz from the Midlands, igneous rocks from Wales, and chert from the Upper Greensand of southeastern England. This exotic rock component was introduced by rivers such as the Bytham River and Proto-Thames.
The Finchley Gap is a location centred on Church End, Finchley, in north London, England. As a topographical feature approximately eight kilometres wide, lying between higher ground to the north-west and to the south-east, it has probably existed for the last one million years or more.
This article describes the geology of the Broads, an area of East Anglia in eastern England characterised by rivers, marshes and shallow lakes (‘broads’). The Broads is designated as a protected landscape with ‘status equivalent to a national park’.
Wells Chalk Pit is a 4-hectare (9.9-acre) biological and geological Site of Special Scientific Interest on the eastern outskirts of Wells-next-the-Sea in Norfolk. It is a Geological Conservation Review site, and it is in the Norfolk Coast Area of Outstanding Natural Beauty.