Richard J.O. Hamblin

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.

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.

The Pleistocene College Farm Silty Clay at Great Blakenham, Suffolk, England – additional information on the course of the early River Thames

The Pleistocene College Farm Silty Clay Member of the Creeting Formation at Great Blakenham, Suffolk, south-east England is shown to contain indigenous and recycled dinoflagellate cysts and other derived palynomorphs. The indigenous dinoflagellate cysts indicate a marine influence during deposition of the clay, whilst the other palynomorphs demonstrate derivation of sediment from a wide catchment of Carboniferous, Jurassic and Cretaceous bedrocks. It is argued, by comparison with palynological data from the Chillesford Clay Member of the Norwich Crag Formation some 25km to the east, that these sediments were eroded from western, south-central and south-eastern Britain, and transported by the early River Thames to its estuary, where they were redeposited at die western margin of the Crag Basin, during the Early Pleistocene Tiglian TC3 Substage. This interpretation refines earlier research which concluded the College Farm Silty Clay was deposited in a predominantly freshwater environment, such as a lagoon, without any direct access to the sea or major river.

Mapping of Quaternary solifluction deposits in southwest England: a tool for planners and the prediction of natural geohazards

Evidence of global climate change is expected to be first seen in polar regions, where subtle changes in climate may have large impacts on fragile geomorphic systems. Polar dunes are one such system for which there is little precise information available. For example, the extent to which polar aeolian deposits are stabilized by ice-bonded sands is unknown. As a first step towards a better understanding of the response of polar desert aeolian systems, we have mapped the sand dunes in Victoria Valley, Antarctica over the past four decades. The dune field is located at the confluence of the Packard and Victoria Valleys and has been the focus of field measurement programs for more than 40 years. Previous studies indicate that dune mobility has been limited to the crests shifting over ice-cemented sand layers within the dune in response to the Valley’s bi-direction wind regime. This is believed to impede net migration of the dune field. Short-term field studies have shown erratic movement of the dunes with the range between –14 and 62 m. However, no study has been made of longer term change in the morphological character of the dune field. In this study we use vertical air photographs and LIDAR data to map dune change over a 43 year period. We assess change in dune position and morphology over time. We find that the dunes have migrated (up to 75 m), and that dune form has changed, principally by lateral coalescing and limb extension. Movement of the dunes suggests that migration is possible despite the presence of ice and snow within the dune core. In addition, these changes support earlier observations that indicate a net (westerly) migration driven by topographically channeled thermally generated easterlies and gradient southeasterly winds. We infer this to indicate that the region has not undergone significant change in weather patterns in the last four decades. This is in agreement with the findings of Ayling and McGowan (2006) who investigated dust deposits on the adjacent Victoria Lower Glacier. Accordingly, it would appear that neither change in weather or climate due to global warming has caused significant change to the meteorology of the Victoria Valley, Antarctica and in-turn its aeolian geomorphic system.Plant macrofossils from permafrost deposits at the Bolshoy Lyakhovsky Island, New Siberian Archipelago, in the Russian Arctic were studied aiming at the revelation of climatic similarities and distinctions between the last and the current interglacial. The plant remains revealed the existence of a shrubland dominated by Alnus fruticosa, Betula nana, and Ledum palustre and interspersed with lakes and grasslands during the last interglacial. The reconstructed vegetation differs fundamentally from the high arctic tundra that exists in this region today, but resembles an open variant of subarctic shrub tundra as occurring near the tree line about 350 km southwest of the study site. Such difference in the plant cover implies that, during the last interglacial, the mean summer temperature was considerably higher, the growing season was longer, and soils outside the range of thermokarst depressions were drier than today. Pollen-based climatic reconstructions using the best modern analogue (BMA) approach suggest a mean temperature of the warmest month (MTWA) range of 914.5 °C during the warmest interval of the last interglacial. Reconstructions from plant macrofossils based on thermal minimum needs of included plants, representing more local environments, gained MTWA values above 12.5 °C in contrast to todays 2.8 °C. We explain this contrast in summer temperature and moisture conditions with a combination of summer insolation higher than present and climatic continentality in arctic Yakutia stronger than present as result of a considerably less inundated Laptev Shelf during the last interglacial. The project was funded by the German Research Foundation (DFG).Over two-thirds of northern and central Britain has been glaciated during the Quaternary, and the present landscape is a relict of the glacial processes that have acted to erode and redistribute large quantities of geological material. The landscape of Southern Britain by contrast, which lay largely beyond the maximum ice extent, was not subjected to such processes. Instead the present form of the landscape reflects approximately 2.5 million years of subaerial weathering under a climate regime, characterized since the onset of the Middle Pleistocene, by a long-term trend of periglacial-Interglacial-periglacial cycles operating with 100ka cyclicty. The effect of this, as preserved with the geological record, has been the extensive in-situ weathering of bedrock materials and the development of thick regolith. Since the region became populated, deforestation and cultivation has progressively removed the vegetation that once acted to stabilize the regolith, and the regolith material is now highly susceptible to erosion by hillwash and solifluction processes. This represents a significant ground stability hazard especially in relation to the subsidence and collapse of roads and property. In addition, large valley accumulations of regolith material can liquefy under prolonged periods of intense rainfall and can result in catastrophic flooding and landslide events, such as those that occurred in Lynmouth in 1952 and more recently, in Boscastle on the north Cornwall coast in 2004. This abstract reports the findings of research undertaken both to map the spatial extent of these regolith deposits, and also to understand what controls their local and regional distribution. The research, based upon field analysis and NEXTMAP digital terrain models from two test areas in southwest England, reveals that the spatial distribution of in-situ and soliflucted regolith material is largely controlled by lithological variability and structural complexity of the bedrock. It is hoped that these models will prove an invaluable to planners to enable informed decision making and the prediction of natural geohazards.QUAVIDA is a new project which aims to understand the interactions among vegetation structure and function, climate and fire regimes during the Late Quaternary. The project targets Australasia as a critical area in the development of a global picture of environmental change. Australasia has experienced major wet/dry, temperature and atmospheric CO2 fluctuations in the past; human arrival and occupation have also had a substantial environmental influence. Much of the vegetation within the region is fire-prone (and fire-adapted), with fire management long and widely practised. We need to understand the natural climate variability, disentangle the role of humans in past changes and investigate how plant types, vegetation and fire regimes will respond to future climate changes. QUAVIDA will do this by using state-of-the-art earth system models in hypothesis-testing mode, running simulations for specific times in the past but with different model components operative and using different scenarios of external and internal forcing. In order to evaluate and interpret these simulations, comprehensive data sets describing palaeoenvironmental conditions at key times in the past will be required. Thus, the first major focus of activity within QUAVIDA has been the creation of a comprehensive database of palaeoenvironmental information from Australasia, covering the last 70,000 years. The database contains radiometrically-dated pollen, phytolith, plant macrofossil, stickrat midden, carbon isotope and charcoal records. Interrogation of this database will yield benchmark reconstructions of vegetation patterns and fire regimes for the evaluation of the model simulations. Using more than one source of palaeoenvironmental information allows differences in the temporal and spatial scale of different kinds of observations to be taken into account in making reconstructions. It also allows for the fact that different sources record different aspects of climate and/or environmental changes. This presentation will introduce QUAVIDA, the methods and preliminary results of the palaeo-data synthesis, and discuss the project’s contribution to the international earth-modelling community.In February 2004, a 4 m core spanning the last ~ 40 ka was retrieved from Native Companion Lagoon (NCL), southeast Queensland, Australia using a Russian D-section corer. Analysis of the top 1 m of the core, which represents the Holocene, identified a pronounced increase in aeolian sedimentation commencing at ~5700 cal BP with peaks in the deposition of wind transported sediment of 12.5 g m−2a at 4690 cal BP and 10.8 g m−2a at 3890 cal BP before decreasing to 0.3 g m−2a at ~2000 cal BP. The increase in aeolian sedimentation ~5700 cal BP was coincident with a pronounced increase in charcoal content of the core, thereby indicating that fire was most likely a key agent in the destabilisation of the local dunes. Geochemical provenance of the long traveled dust component of the record identified western Queensland and southwestern New South Wales as the dominant source areas. Analysis of pollens from the core indicate a reduction in aquatics similar to that reported by Donders et al. (2006) for Lake Allom, Fraser Island, while there was also a reduction in rainforest and pteridophytes. As a result, we believe that this period of increased aeolian sedimentation was caused by prolonged and severe drought possibly linked to the onset of ENSO type conditions in the mid-Holocene as reported by Moy et al. (2002) and Gagan et al. (2004). Through analogy with contemporary ENSO events, precipitation bearing southeasterly trade winds would have been suppressed and replaced by more frequent and dry west to southwesterly winds as indicated by the provenance of far traveled dust to west and southwestern source areas. Importantly, the NCL record identifies southeast Queensland as a region susceptible to prolonged and severe drought as a consequence of more persistent ENSO type conditions. Recent modeling studies suggest that ENSO type conditions may transform from their current interannual variability into the mean climate as a consequence of global warming. Our results suggest that if this was to occur, then southeast Queensland may experience the onset of another arid phase.A high resolution pollen record from the ODP 820 marine core for the last million years is presented. It is chronologically controlled by marine stratigraphic data.This record provides a picture of substantial vegetation and environmental change for the humid tropics region of northeastern Australia. It is the first largely continuous record in Australia to cover this length of time in any detail, although sediment accumulation rates decrease with increasing age. The influence of orbital forcing (particularly eccentricity and obliquity) is clearly present in the record providing good support for the proposed age model based on the marine stratigraphy, but each isotope stage contains some distinctive features. Superimposed on these cyclical patterns are abrupt and sustained changes in the representation of many taxa and community types that may be explained by a combination of regional changes in oceanic and atmospheric circulation systems throughout this time period, along with the impacts of people in the later part of the record (i.e. last 45,000 years BP).