Brian M. Funnell

Early and early Middle Pleistocene correlations in the Southern North Sea basin

Abstract On April 8, 1988 a discussion meeting took place at Norwich with the aim of establishing correlations of the Early and Middle Pleistocene stages across the southern North Sea. On the basis of faunal, floral, and palaeoclimatic data the following correlations were considered highly probable. The Pastonian Stage of East Anglia is correlated with the Late Tiglian (TC5) Stage of the Netherlands, and the Bramertonian with the Middle Tiglian (TC1-4b). The possibility that the British Antian and Bramertonian Stages may represent parts of a single climatic event is mentioned. The Ludhamian is probably of Early Tiglian age and the Pre-Ludhamian may equate in part with the Praetiglian Stage. Possible correlation of the Waltonian with part of the Pliocene Reuverian Stage is also suggested. In the later Middle Pleistocene, the Anglian Stage correlates with the continental Elsterian. The precise correlation of the British type Cromerian Stage with part of the ‘Cromerian Complex’ Stage in the Netherlands remains uncertain.

Plio-pleistocene palaeogeography of the southern north sea basin (3.75-0.60 Ma)

Abstract Palaeogeographical maps are presented for the southern North Sea basin, from approximately 1°W to 7°E, and 51–55°N, for the period from approximately 3.75-0.60 Ma. Reconstructions centre on: 3.75 Ma (Coralline CragBrunssumian); 2.55 Ma (Red Crag/Brielle Ground/Reuverian); 2.40 Ma (Red Crag/Westkapelle Ground/Praetiglian-Early Tiglian); 2.00 Ma (Norwich Crag/Smiths Knoll and IJmuiden Ground/Middle Tiglian); 1.75-1.70 Ma (Cromer Forest Bed (Paston)/Winterton Shoal/Late Tiglian-Eburonian); 1.40 Ma (Kesgrave/Yarmouth Roads/Waalian); 1.15 Ma (Kesgrave/Yarmouth Roads/Menapian); and 0.60 Ma (Cromer Forest Bed (West Runton)/Yarmouth Roads/Cromerian Complex). From 3.75-2.40 Ma the basin is mainly a marine area fringed to the east and south by fluviatile deposition, and broadly open via the southwest to the Atlantic. Following marked marine regression and cooling at around 2.40 Ma, the period from 2.00-1.70 Ma is mainly one of renewed marine transgression and warmer conditions, during which a Great European delta built out, fed mainly from the east and south, into the southern North Sea. From 1.40-0.60 Ma marine waters were almost entirely excluded from the area, and temperate intervals alternated with increasingly glacial episodes, whilst the Great European delta continued to expand northwards into the northern North Sea.

Sedimentary evolution of the north Norfolk barrier coastline in the context of Holocene sea-level change

Abstract Holocene sediments of the north Norfolk coast (NNC) between Weybourne and Hunstanton have been studied using geophysical, sedimentological, biofacial and dating techniques. New cores and refraction seismic data have defined the topography of the pre-Holocene surface and show that the NNC sediment prism is underlain by an east-west trending Quaternary trough, probably a palaeo-river-valley. The age of the Holocene fill has been dated using radiocarbon and luminescence dates, while sedimentation rates were constrained by, and compared with, modern rates using radionuclide data. The Holocene sediments are divided into a sandy-barrier lithofacies association (LFA), and a muddy-silty-peat back-barrier LFA. The oldest Holocene sediments are peats, formed on an undulating till surface. These peats were forming by 11-10 cal. ka bp and continued to form until at least 7 cal. ka bp in a number of places. As Holocene sea-level rose, marine mudflat and saltmarsh environments began to form between 7 and 6 cal. ka bp east of Holkham and around 6 cal. ka bp or younger west of Holkham. A marked erosion surface between the barrier and back-barrier LFA in the Holkham to Burnham Overy area is imperfectly dated at <3 cal. ka bp, but suggests the sediment prism has thinned by about 3 km over 6 to c. 3cal. ka bp. This surface probably records the westward progress of laterally migrating tidal channels that caused back-barrier sediment erosion, along with shoreface processes, as sea-level rose. Small-scale regressive and transgressive saltmarsh sequences occur at different elevations along strike but cannot be correlated, suggesting that the control on saltmarsh and mudflat development is autocyclic rather than allocyclic. Generally, transgressive and regressive events are related to disposition of coastal barriers and these are superimposed on a general facies evolution governed by regional sea-level change. Predictions about how this barrier coastline might respond to increased rates of regional sea-level change caused by global warming, or climatic events like increased storminess, require an understanding of how specific segments of the coastline have responded over millennial time-scales. This longer-term evolution provides the baseline information for decision making and management strategy. It is likely that sandy sediment supply is limited on the NNC and this implies that the barriers will continue to move landward, probably at increased rates relative to today, suggesting that parts of the NNC will become more vulnerable to erosion and flooding.

Planktonic foraminifera from the Pliocene Coralline Crag of Suffolk, Eastern England

Nine species of planktonic foraminifera have recently been identified from the Coralline Crag of Suffolk, Eastern England. Stratigraphically important species include Globorotalia puncticulata (Deshayes) and Neogloboquadrina atlantica (Berggren) whose joint ranges, based on evidence from the North Atlantic, indicate an age for the deposit of between c. 4.2 and 2.3 Ma; other published evidence suggests that it may not be younger than c. 3.4 Ma. The low planktonic foraminiferal species diversity is interpreted as being due to a combination of factors, including the shallow water nature of the Coralline Crag, which would preclude deeper water species of planktonic foraminifera, and the possibility that the source of the fauna was from relatively high latitudes of the North Atlantic via the northern entrance to the North Sea. The planktonic foraminifera recorded indicate that the water temperature of the sea was within the range 10–18°C. The Coralline Crag contains very rich Lusitanian faunas of gastropod and bivalve molluscs, bryozoans, ostracods and benthic foraminifera.

Sedimentary environments and Holocene evolution of the lower Blyth estuary, Suffolk (England), and a comparison with other East Anglian coastal sequences

The Holocene sequence of the lower Blyth estuary in north Suffolk comprises four main lithostratigraphical units; a basal freshwater Lower Peat, overlain by estuarine Lower Clay, then Middle Peat and Upper Clay representing two phases of transgressive overlap sandwiching a phase of regressive overlap. Peat formation began about 6750 14 C years BP and continued until 6500 14 C years BP when the sequence was inundated and eroded by marine waters during the first transgressive overlap. Rapid changes in the physical character of the environment and extensive mortality of organisms during the initial stages of transgressive overlap are indicated by a well defined shelly horizon covering the Lower Clay/Lower Peat boundary. Estuarine silt/clay deposition persisted until about 4500 14 C years BP when a transition to further peat growth occurred. The second phase of estuarine sedimentation, which is transitional from the underlying Middle Peat, began at about 4300 14 C years BP. A minor phase of regressive overlap took place sometime during the deposition of the Upper Clay. The Blyth valley dates correlate well with dates for similar tendencies of sea-level movement in the Fens, north Norfolk and Broadland. The Blyth sequence contrasts with the Holocene sequences in the Deben, Orwell and Stour estuaries in south Suffolk which comprise a continuous estuarine clastic sequence without intercalated peats. Estuarine conditions are believed to have begun about 8000 years BP and low sediment accumulation rates allowed these estuaries to remain flooded throughout the Holocene.

Holocene evolution of the Blakeney Spit area of the North Norfolk coastline

Blakeney Spit extends more than 12 km along the North Norfolk coast, from its origin near Weyboume in the east, to a location opposite a point halfway between Morston and Stiffkey in the west. Borehole investigations landward of the spit have revealed remarkably uniform sequences of intertidal sediments, sometimes passing from lower intertidal muds into upper intertidal saltmarsh, sometimes being rather uniform upper saltmarsh throughout. Similar intertidal sediments are found landward of an inter-tidal barrier extending from off Stiffkey to off Wells. The thickness of these deposits, resting either on glacial deposits or directly on Chalk, reaches over 15 m in places, along the line of an original E-W trough or channel. Adequate radiocarbon and other reliable dating of these deposits has proved somewhat difficult to determine, but the earliest are Post-Glacial non-marine deposits as old as 10 000 years bp , with the initiation of marine deposition at c . 7500-6500 years bp at the eastern end of the sector. Apart from the Stiffkey and Morston mainly gravel and sandy ‘Meals’ barriers, which are resting on top of saltmarsh deposits and probably date back to no more than 670-900 years bp , there are no other sand or shingle deposits, except in drainage channels, anywhere landward of Blakeney Spit. The spit itself is being produced by the erosion of the cliffs east of Weybourne, and the entire Holocene and glacial sequences on its seaward side, rolling the sand and shingle body over landward (at about 1 m per annum), and prograding westward, (at c . 3.5 m per annum) - as indicated by accurate maps constructed over the last 400 years.

Offshore transport of neritic diatoms as indicators of surface current and trade wind strength in the Plio-Pleistocene eastern equatorial Pacific

Abstract The taphonomy of neritic diatoms entrained into, and transported offshore by, the Peru and South Equatorial currents may represent fluctuations in surface current and southeast trade wind strength in the eastern equatorial Pacific (EEP). This proposition was investigated through the construction of a neritic/pelagic diatom ratio (NPDR) which is compared with other palaeoceanographic proxies analysed through the Olduvai timeslab (ca. 2.0–1.75 Ma) at Ocean Drilling Program sites 677, 847 and 851: a new sea-surface temperature (SST) record for all the sites is derived from a diatom transfer function, and upwelling and bioproductivity records are provided by previously published radiolarian and CaCO3 data, respectively, for site 677 only. Results indicate a consistent relationship between proxy records, suggesting that the presence of neritic diatoms in pelagic sediments are most likely attributable to surface current and trade wind variability. The NPDR has the potential of becoming an extremely useful micropalaeontological tool in multi-proxy palaeoceanographic studies of coastal upwelling systems. The palaeoceanographic history of the Olduvai timeslab in the EEP, as indicated by previous studies, is supported and enhanced by the NPDR and new SST data reported here. The early and late periods of the Olduvai timeslab are characterised by strong upwelling, low SST, and high bioproductivity, and increased trade wind strengths inferred from the NPDR. The mid-Olduvai (1.80–1.90 Ma) appears to have been a period of weaker upwelling, higher SSTs, lower bioproductivity and decreased trade wind strength as indicated by the NPDR. The NPDR is important as it increases our understanding of the relationship between palaeoceanographic processes and trade wind strength in the region.

Engineering Characteristics of East Anglian Quaternary Deposits

Summary Approximately 80 per cent of the surface of East Anglia is composed of Quaternary deposits, and even where it is made up of pre-Quaternary deposits these are highly likely to have been modified by glacial and periglacial processes. The initial Quaternary deposits consist of pre-glacial marine, estuarine and freshwater gravels, sands, clays and peats. Widespread glacial tills and outwash sands and gravels form the middle part of the succession. Later fluvioglacial and fluvial and marine inter glacial sands and gravels occupy the major valleys and some coastal sites. Post-glacial deposits consist of extensive freshwater and marine alluvial peats and clays at lower elevations in the major valleys and in the coastal zone. This account briefly reviews some qualitative engineering characteristics of these East Anglian Quaternary deposits, and provides references to further sources of information on them.

Low-latitude Plio-Pleistocene temporal abundance variations in the radiolarian Cycladophora davisiana Ehrenberg: stratigraphic and palaeoceanographic significance

Abstract The abundance variation of the radiolarian Cycladophora davisiana was recorded throughout the Plio-Pleistocene Olduvai Time-slab of Ocean Drilling Program (ODP) Sites 677, 709, 847, 850 and 851, in the equatorial Pacific and Indian Oceans. Data were plotted on independently erected timescales. Twelve peak-abundance events were recognized, although not all events were recognized at all the sites. Most of the events, where they are recorded at different sites, were synchronous. However, events recorded at Site 709 in the Indian Ocean were found to be approximately 15 ka older than those events recorded at Pacific sites. This age difference may be due to either diachronous C. davisiana events or a slight inaccuracy in the erected timescale for ODP Site 709 compared with those of the eastern Pacific. The previously demonstrated synchroneity of C. davisiana events in the Late Quaternary leads us to believe that the ODP Site 709 timescale may be inaccurate. Thus, recognition of correlatable C. davisiana events in the equatorial Pacific and Indian Oceans permits the further evaluation and fine-tuning of high-resolution timescales, enabling accurate comparisons to be made of sediment sequences on a regional, and possibly oceanic and interoceanic scale. Of the 12 C. davisiana events recognized, only one event occurred at all the investigated sites. This event occurred at c.1.8 Ma and immediately above the internationally defined Pliocene-Pleistocene boundary, and may thus prove to be a new useful biostratigraphic marker for the Tertiary/Quaternary boundary. C. davisiana is primarily characteristic of high-latitude water masses, therefore the cyclical abundance peaks of this species noted at the low-latitude sites investigated here, represent the injection of deep cold water of high-latitude origin.

Benthic Foraminifera from Middle to Late Pleistocene, coastal upwelling sediments of ODP Hole 686B, Pacific Ocean, off Peru

Benthic Foraminifera from middle to late Pleistocene, (c. 600ka to 0ka), sediments of ODP Hole 686B, off Peru, show highest abundances and diversities during periods of cooler surface waters, (inferred from the Uk37 index), and enhanced upwelling, (inferred from the peridinacean/gonyaulacacean dinoflagellate cyst ratio). During the latest Pleistocene, (c. 160ka to 0ka), these periods are characterised by higher organic carbon contents in the bottom sediments, and occur during the odd-numbered, interglacial_18O stages. The benthic Foraminifera indicate deposition in 120 to 250 metres water depth for the earlier part of the record, (c. 600ka to c. 200ka), within the oxygen-minimum zone, with bottom water oxygen contents of <0.5 to 0.2 ml/l, (inferred from the dominance of Bolivinellina humilis). Deposition in water depths approaching those of the present day, (c. 450 metres), is indicated from c. 160ka onwards, with better oxygenated bottom water conditions, probably corresponding to the lower part of the oxygen-minimum zone.