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The Holocene sequence of the Humber Estuary displays a wide range of sediment types within which the preservation of microfossils is highly variable. Its evolution has been reconstructed using a range of environmental proxies with chronological control provided by more than 90 radiocarbon dates. Results are presented of diatom analyses from three cores typical of the inner, middle and outer estuary (HMB20, HMB7 and HMB12) and of three cores that illustrate the role of organic deposits (peats) and their associated pollen (HMB 13, HMB12 and the Ancholme Valley) in the definition of sea-level index points. The reconstruction of relative sea-level change shows a rapid rise in the early Holocene, followed by a reduced rate of rise in the mid-late Holocene. This reconstruction, together with information on the pre-Holocene surface and the different palaeoenvironments from the cores have been integrated within a geographical information system and then interpreted to yield a series of palaeogeographical maps of the Humber at 1000-year time slices between 8 and 3cal. kaBP. The marine transgression progressed up the estuary after 8cal. kaBP, reaching the inner estuary by 6 cal. ka BP. The expansion of intertidal environments probably reached its maximum around 3cal. ka BP. Changes since 3 cal. kaBP are described using archaeological and historical records. Tidal asymmetry is a major controlling factor on the balance of sediment accretion and erosion in the estuary. Sedimentary and bathymetric evidence suggests a damped oscillation between flood and ebb asymmetry in the Humber over the Holocene period. Such a conclusion would be of great importance to estuarine managers and users since it could be used to predict the future development of the estuary.

In order to determine the processes that have governed the accumulation and erosion of sediments in the Humber Estuary (English North Sea coast) through the Holocene, the character, volume and source of sediments were studied. Eight sediment suites were identified on the basis of chemostratigraphy, lithostratigraphy and mineralogy. The locally sourced, freshwater, Basal Suite is overlain by the Newland and Butterwick Suites, deposited between c. 8 and 7.4 cal. ka bp in brackish environments behind a morainic barrier at St Andrew’s Dock, Hull. These are overlain by the largely marine, saltmarsh sediments of the Garthorpe Suite, which in turn are overlain, with erosional contact, by the channel sandflat and mudflat deposits of the Saltend, Sunk Island and Skeffling Suites. Most of the Saltend Suite is likely to have been deposited since c. 4 ka ago, whilst the Sunk Island and Skeffling Suites are likely to have been deposited since Medieval times and from the late eighteenth century onwards, respectively, as indicated by their concentrations of anthropogenic metals. On the coast, the Spurn Suite consists of sediments, associated with a spit system, which are almost entirely marine in origin. The suites show a progressive increase in marine influence; sediments of the oldest suite being entirely from the terrestrial catchment, those of the younger suites from erosion of the North Sea floor and coast. The relationships between suites show that during the last 4 ka the geomorphological evolution of the estuary has been marked by widespread erosion episodes that have led to the partial removal or redistribution of earlier deposits. By modelling the volumes of the suites it can be shown that, of the total volume of the estuarine fill (9.6 km3), over half is likely to have been deposited during this period.

21This paper provides an overview of regional geochemical mapping using stream 22 sediments from central and south-western Nigeria. A total of 1569 stream sediment 23 samples were collected and 54 major and trace elements determined by ICP-MS and 24Au, Pd and Pt by fire assay. Geostatistical techniques (e.g. correlation analysis and 25 principal factor analysis) were used to explore the data, following appropriate data 26 transformation, to understand the data structure, investigate underlying processes 27 controlling spatial geochemical variability and identify element associations.