Middle to late Pleistocene palaeoecological reconstructions and palaeotemperature estimates for cold/cool stage deposits at Whittlesey, eastern England

Fossiliferous beds in a complex sequence of late Middle to Late Pleistocene deposits at Whittlesey, eastern England, provided a rare opportunity for a multidisciplinary study of the palaeoecology of cool/cold stage deposits from different glacial stages. The fossiliferous sediments investigated form part of the River Nene 1st Terrace. Three of the four fossil assemblages investigated pre-date the last interglacial stage (Ipswichian/Eemian/marine oxygen isotope stage (MIS) 5e), whereas the other dates to part of the MIS 3 interstadial complex (Middle Devensian/Weichselian). Pollen, plant macrofossil, molluscan, coleopteran, ostracod, foraminifera and vertebrate data are available to a greater or lesser extent for each cool/cold stage assemblage, and they broadly present the same ecological picture for each one: a continuum from low-energy permanent to non-permanent aquatic habitats through marshland with associated waterside taxa, together with flood influxes of fluvial, riparian and ruderal taxa. Although each fossil assemblage records cool/cold climatic conditions, to a greater or lesser extent, these conditions are more apparent in the insect and ostracod faunas. In comparison with results published for the Last Glacial Maximum (LGM) stadial in The Netherlands, palaeotemperature estimates based on ranges of mutual agreement between independent coleopteran and ostracod methods for the three pre-Ipswichian/Eemian assemblages indicate minimum mean July air temperatures that are from +1° to +3 °C warmer, but January values that embrace the −8 °C estimate for the LGM. There is, however, a disparity between the coleopteran and ostracod palaeotemperature estimates for the Middle Devensian/Weichselian fossil assemblage, which are based on two different sample stratigraphic levels; the lower, coleopteran assemblage is indicative of very cool, continental climates, whereas the stratigraphically slightly higher ostracod assemblage suggests a climatic amelioration. Lack of numerical age-estimates prevents a robust stratigraphical interpretation, but the youngest pre-Ipswichian/Eemian fossil assemblage could date to the MIS 7–6 transition, at a time when cooling possibly preceded glacially driven sea-level fall. It is apparent from the rich coleopteran data that some continental cold-indicator taxa also appeared in pre-Ipswichian/Eemian cold stages and therefore assignment of continental cold-indicator taxa to particular Devensian/Weichselian intervals should be undertaken with care

Improving chronological control for environmental sequences from the last glacial period

Recognition of palaeoclimatic instability in the Greenland ice cores has spurred researchers to identify corresponding evidence in other terrestrial records from the last glacial stage. Such evidence is critical for establishing how much environmental stress precipitated Neanderthal and Late Pleistocene megafaunal extinctions, although a need for improved chronology has been consistently highlighted. In formerly glaciated and periglaciated areas of northern Europe, palaeoenvironmental sequences are frequently discontinuous. These often yield high-resolution proxy-based quantitative palaeotemperature estimates but can be hard to date, due to difficulties in removing contamination from biological samples at the limits of the radiocarbon technique (c.30-50kya). Here we demonstrate, for the first time using samples with independent age control, that different radiocarbon pretreatments can generate different age data and that gentler, less effective treatments applied to avoid sample loss may not yield reliable age-estimates. We advocate alternative harsher pretreatment using a strong acid-base-acid protocol. This provides an acceptable balance between contamination removal and excessive sample loss and generates more accurate ages, significantly enhancing our ability to detect and understand the impacts of palaeoclimatic instability in the terrestrial record of the last glacial

The current state of the use of large wood in river restoration and management

Trees fall naturally into rivers generating flow heterogeneity, inducing geomorphological features, and creating habitats for biota. Wood is increasingly used in restoration projects and the potential of wood acting as leaky barriers to deliver natural flood management by “slowing the flow” is recognised. However, wood in rivers can pose a risk to infrastructure and locally increase flood hazards. The aim of this paper is to provide an up-to-date summary of the benefits and risks associated with using wood to promote geomorphological processes to restore and manage rivers. This summary was developed through a workshop that brought together academics, river managers, restoration practitioners and consultants in the UK to share science and best-practice on wood in rivers. A consensus was developed on four key issues: (i) hydro-geomorphological effects, (ii) current use in restoration and management, (iii) uncertainties and risks, and (iv) tools and guidance required to inform process-based restoration and management

Sedimentological, palaeogeographical and stratigraphical aspects of the Middle pleistocene geology of the Peterborough area, eastern England

Available from British Library Document Supply Centre-DSC:DXN038875 / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

On balanced sets and related structures (Algebraic Combinatorics)

Table S7. Thermophile species in channel C and at other Ipswichian sites according to pollen biozonation

Age-estimate evidence for Middle-Late Pleistocene aggradation of River Nene 1st Terrace deposits at Whittlesey, eastern England

At Whittlesey, eastern England, Pleistocene interglacial sediments (unit G3) deposited in marine oxygen isotope stage (MIS) 7 appear to be truncated by a sequence comprising: (i) a limestone-rich gravel containing organic mud beds (unit F1); (ii) vertically aggrading gravel beds with sand-clay-lined bases (unit F2); and (iii) interbedded sands and gravels (units F4–F6) with associated overbank deposits (unit G4). Preliminary investigations of the floral and faunal assemblages of the organic muds were consistent in providing evidence for deposition under cool conditions. This apparent single cool/cold-phase sequence therefore could have been deposited in either MIS 6 or MIS 5d−2. The presence of sand beds in units F5, F6 and G4 and of molluscs in the organic mud beds of unit F1 provided the opportunity for obtaining age estimates using optically stimulated luminescence (OSL) and amino acid racemization (AAR). Rather than a single cool/cold-phase sequence the age-estimate data revealed multiphase aggradation, with the AAR data indicating the possibility that the organic muds in unit F1 were deposited earlier in MIS 7 than the interglacial deposits of unit G3. Therefore, the succession could be: unit F1 was truncated initially by unit G3, with unit F2 subsequently incising both unit F1 and unit G3. The OSL age estimates indicate that units F5, F6 and G4 are Early to Middle Devensian in age (MIS 5d-2), and therefore unit F2 was deposited sometime between late MIS 7 and MIS 5d. This paper has demonstrated the utility of using dual age-estimate techniques in dating complex fluvial sequences. Furthermore, the organic mud beds of unit F1 could provide important new information on the complex character of the MIS 7 interglacial. In addition, the OSL data and the fluvial style recorded by units F4–F6 and G4 allow comparisons to be made with recent investigations of nearby Devensian deposits