B.S.P. Moorlock

Pre-Anglian fluvial and coastal deposits in Eastern England: lithostratigraphy and palaeoenvironments

Abstract Clast lithology and derived microflora are used to provide a basis for correlating pre-Anglian fluvial and coastal deposits in eastern England and to provide a lithostratigraphic framework for these Early and early Middle Pleistocene sediments. Three fluvial systems are recognised. (i) The Thames, which drained an area from Wales through midland England to the Thames basin and southern East Anglia. The catchment was truncated over the period concerned and the western headwaters diverted to other river systems. (ii) The Bytham river which drained midland England and the southern Pennines and reached the southern North Sea delta in the region of north central East Anglia. This river extended its catchment over the period concerned. (iii) The Ancaster river which drained the southern Pennines and received sediment from northeast England. Each of these catchments contributed sediment to the southern North Sea delta/estuary and contributed to the lithologies of the Red, Norwich, and Wroxham Crag formations. The lithostratigraphic subdivisions are based on the fact that: (i) the Pliocene and Early Pleistocene rivers and the equivalent Red and Norwich Crags are characterised by far-travelled microflora which was transported in suspension and a locally derived clast assemblage transported as bedload, and (ii) the later Early and early Middle Pleistocene rivers and the equivalent Wroxham Crag are characterised by a far-travelled microflora and a far-travelled clast assemblage. Variations in the amount and composition of far-travelled materials is determined by the relative importance of the three river systems. This provides a basis for identifying different formations of the Thames river sediments (older Sudbury Formation and younger Colchester Formation) and different members of the Wroxham Formation (Dobbs Plantation Member: local material with minor components of Thames and Ancaster river sediments; How Hill Member: local material with major components of Thames and Ancaster river sediments; Mundesley Member with major components of Bytham river sediments). These lithostratigraphic units are related to established North European biostratigraphy and Oxygen Isotope stratigraphy. The factors forcing the changes in river energetics are explained in terms of the relative importance of geomorphic processes operating within the river catchments determined by the patterns of Milankovitch orbital forcing.

Revised Pre-Devensian glacial stratigraphy in Norfolk, England, based on mapping and till provenance

Mapping combined with till provenance studies have resulted in a re-appraisal of the pre-Devensian glacial stratigraphy of Norfolk, England. The traditional model invoked two formations, a North Sea Drift Formation (NSDF) overlain by a Lowestoft Formation, formed by co-existing icesheets originating in Scandinavia and Northern Britain respectively. The NSDF included three diamictons, the First, Second and Third Cromer tills. The Briton’s Lane Sands and Gravels were considered to overlie the Lowestoft Formation. However, our work has shown this stratigraphy to be untenable, and we propose a model of several glaciations instead of co-existing ice-sheets. In our revised stratigraphy, the oldest formation, the Happisburgh Formation (including the Happisburgh or First Cromer Till) includes massive, sandy tills derived from northern Britain. The overlying Lowestoft Formation, including the Second Cromer (Walcott) Till is confirmed as derived from the west, introducing much Jurassic material as well as Chalk. The Sheringham Cliffs Formation includes both brown sandy tills (the Third Cromer Till) and ‘marly drift’, in a variety of tectonic relationships, and derived from the north and NNW. Finally the Briton’s Lane Formation is the only formation to include Scandinavian erratics. Dating of the four formations is at varying levels of confidence, with the Lowestoft Formation most confidently confirmed as MIS 12. The Happisburgh Formation is believed to represent an earlier glaciation, and MIS 16 is proposed. The Sheringham Cliffs Formation is tentatively believed to date from MIS 10, and the Briton’s Lane Formation is assigned to MIS 6.

Early and early Middle Pleistocene river, coastal and neotectonic processes, southeast Norfolk, England

This paper investigates the interaction between coastal and river processes and neotectonics, prior to glaciation of northern East Anglia, eastern England. The study is based on results obtained from two boreholes drilled into the plateau of southeast Norfolk, between the Yare and Waveney valleys. Diagnostic sedimentary and lithological indicators from core samples are used to describe the main lithological units, and to compare them with the type sites of the Norwich Crag, and members of the Bytham Sands and Gravels, and Corton Formation. The results provide evidence for coastal sedimentation in the Early Pleistocene, when the Norwich and Wroxham Crags were deposited, and evidence to establish links between the coastal deposits and the contemporary river systems. The Norwich Crag received only suspended sediment from low energy rivers, whereas the Wroxham Crag received bedload transported from the whole catchment. Neotectonic subsidence within the region is proposed to explain the transgression of the Wroxham Crag across the Norwich Crag. The succeeding stratigraphical units are fluvial sediments of the Bytham river, which was the major river draining Midland England during the Middle Pleistocene. These sediments are located in a valley cut into the Crag, indicating uplift between the deposition of the coastal and river deposits. After their deposition, the whole region was overridden by glaciers that deposited the sediments of the Corton and Lowestoft formations, and shifted the Bytham river to a more southerly route.

Middle Pleistocene sedimentology and lithostratigraphy of Weybourne northeast Norfolk, England

This paper investigates pre-glacial and glacial deposits exposed in coastal cliff sections of the Weybourne area, northeast Norfolk. At this site, shallow-marine sediments of the early Middle Pleistocene Wroxham Crag Formation are overlain by two glaciotectonized and interbedded tills and glaciofluvial sands and gravels of Middle Pleistocene age. The lower sandy Runton Till (Third Cromer Till) is tectonized and incorporated into the overlying chalk-rich till forming the banded Weybourne Town Till (Marly Drift). Structures within these tills indicate that they were deposited subglacially and the two till lithologies were intermixed as the water-saturated Runton Till was remoulded and assimilated within the banded and chalk-rich Weybourne Town Till. Although the Runton Till has been traditionally attributed to deposition by a Scandinavian-based ice sheet, clast lithologies indicate that both the Runton and Weybourne Town tills were deposited by a Scottish-based ice-advance that moved down the coast of eastern England. The overlying sand and gravel succession, preserved only in large synform ‘sag-basins’ is interpreted as glacial outwash on the basis of its sedimentology and clast lithology, and is correlated with the Britons Lane Sand and Gravel by the presence of a Scandinavian clast component.

The Red Crag and Norwich Crag formations in eastern Suffolk

The Red Crag Formation of eastern Suffolk was deposited in structurally controlled basins during the Pre-Ludhamian, Ludhamian and Thurnian stages. A regression during the Thurnian was followed by a transgression during the Antian/Bramertonian Stage, with the Norwich Crag Formation resting unconformably on strata as old as Upper Cretaceous. A regression during the Baventian Stage led to the formation of a complex of shoreface gravels (Westleton Beds) and intertidal clays at the mouth of a river which flowed from the English Midlands to reach the sea in the Southwold area. The Chillesford Clay Member was formed penecontemporaneously at the estuary of the proto-Thames, further south. A further marine transgression occurred during the Pastonian. The Pre-Ludhamian, Antian/Bramertonian and Pastonian transgressions are tentatively correlated with the reflectors respectively at the base of the Westkapelle Ground, Smiths Knoll and Winterton Shoal formations of the southern North Sea.

The Glacial History of the British Isles during the Early and Middle Pleistocene: Implications for the long-term development of the British Ice Sheet

Abstract We review the evidence for Quaternary glaciation in the British Isles and adjoining seas. Attention is given to the types of onshore and offshore evidence and the robustness of these evidence sources. We find evidence for onshore lowland glaciation during Marine Isotope Stages 16, 12, 10, 6 and 2.

Reworked and indigenous palynomorphs from the Norwich Crag Formation (Pleistocene) of eastern Suffolk: implications for provenance, palaeogeography and climate

Analysis of samples of clays from the Pleistocene Norwich Crag Formation near Southwold in eastern Suffolk, England has revealed the presence of relatively abundant reworked palynomorphs derived from Carboniferous, Jurassic, Cretaceous and Palaeogene strata. A further sample of similar age from a borehole at Sudbourne, near Ipswich, contains additional evidence for the reworking of Silurian sediments. The presence of the derived palynomorphs is consistent with input from rivers flowing eastwards into the western margin of the Crag depositional basin during the Baventian. The input in the Southwold area was via the forerunner of the Byfham River, a river which flowed from the English Midlands to the East Anglian coast prior to the onset of the Anglian glaciation. The proto-Thames is argued as the transporting medium for the Silurian palynomorphs in the Sudbourne sample.

Reworked palynomorphs from the Red Crag and Norwich Crag formations (Early Pleistocene) of the Ludham Borehole, Norfolk

Early Pleistocene estuaries in Norfolk and Suffolk were supplied by at least three large rivers which transported clastic material from several Carboniferous to Palaeogene formations in southern, central and northeastern England. New palynological data on eight samples from the Pleistocene Crag Group (Red Crag and Norwich Crag formations) of the Ludham Borehole, Norfolk add significant detail to this palaeogeographical reconstruction, revealing the consistent presence of reworked palynomorphs of Carboniferous, Jurassic, Cretaceous and Palaeogene age. The presence of these allochthonous palynomorphs is attributed to fluvial debris from a major river which flowed into Norfolk from the west and northwest. The provenance of the sediment supply can be frequently identified to formational level.

The origin of the Norwich Brickearth: micromorphological evidence for pedological alteration of sandy Anglian Till in northeast Norfolk

Micromorphological analysis of Norwich Brickearth reveals evidence for substantial soil modification, with the formation of a highly stressed matrix fabric, silt and clay coatings around sand grains, clay and silty-clay coatings around voids, and zones of clay concentration. Along with evidence for decalcification and colour change and a slight increase in clay content, these results indicate that the Norwich Brickearth is sandy till which was originally deposited during the Anglian Glaciation in northeast Norfolk and has subsequently been pedologically altered under temperate and cold climatic conditions. In this respect the Norwich Brickearth is a relict palaeosol similar to the pedologically altered Devensian tills of east Yorkshire, previously know as the ‘Hessle till’. It is recommended that, like the term ‘Hessle till’, ‘Norwich Brickearth’ is not an appropriate Quaternary lithostratigraphic term.

Pre-glacial drainage of Fenland

Summary Although remains of the Bytham river system have been eroded from The Wash and Fen Basin, the evidence to the west and east remains substantial in the form of a wide range of accessible sedimentary and landform evidence. The features of The Wash and Fen Basin cited as evidence for a south-north pre-Anglian drainage system can be explained by glacial erosion during the Anglian Stage.