Thomas C.B. Hill

Holocene sea-level change in the Severn Estuary, southwest England: a diatom-based sea-level transfer function for macrotidal settings

The recent growth in the use of microfossil-based transfer functions in late-Quaternary sea-level reconstructions reflects their potential to accurately quantify palaeo sea-level changes. This study details the development of a diatom-based sea-level transfer function for the Severn Estuary, southwest England, a macrotidal setting that experiences the second highest tidal range in the world. This setting presents difficulties in representing the full tidal range from mean sea level (MSL) to highest astronomical tide (HAT). However, two separate transects were merged successfully and a statistically significant relationship between contemporary diatom assemblages and altitude (m O.D.) was established. A diatom-based transfer function for palaeoaltitude was developed using weighted averaging (WA), tolerance downweighted weighted averaging (WA-Tol) and weighted averaging partial least squares (WA-PLS). WA-Tol produced the lowest prediction errors for altitude and the transfer function was applied to a fossil diatom data set from Gordano Valley, a site adjacent to the Severn Estuary.

The John Williams Index of Palaeopalynology

The John Williams Index of Palaeopalynology (JWIP) is the result of the lifetimes work of Dr John E. Williams. Housed at the Department of Palaeontology of The Natural History Museum (NHM) in London, the JWIP is publically available and provides probably the most comprehensive fully cross-referenced catalogue on palaeopalynology in the world. It has 23,350 references to fossil palynomorph genera or species as of February 2012. Since its inception in 1971, every publication in the collection referring to a fossil palynomorph genus or species has been critiqued by John E. Williams. Each item is given an accession number and appropriately referenced within the JWIP using index cards which are sorted alphabetically. Once added to the main reference subindex, further entries are completed for four themed subindexes. The first three of these are sets of cards on the three major palynomorph groups (acritarchs/dinoflagellate cysts, chitinozoa and pollen/spores), 26 stratigraphical intervals and 17 geographical areas. The fourth themed subindex is where each palynomorph taxon has a card (or cards) listing all the records of that species in the literature within six categories (acritarchs, dinoflagellate cysts, chitinozoa, fungal spores, pollen/spores and miscellaneous). Due to the sustained and meticulous recording of data since 1971, users can therefore search the database by major palynomorph group, species, age and/or geographical region. The comprehensive and cross-referenced nature of the JWIP means that researchers can readily identify key publications on, for example, specific palynomorph types over a particular interval in a prescribed area. The JWIP is currently entirely analogue, but the NHM is currently evaluating potential strategies for digitisation.

Palaeoenvironmental investigations of the River Chelmer, Chelmsford, Essex, UK,

ABSTRACT The value of understanding the landscape context within which sites of human occupation are situated is key to understanding their function and locality. The recovery of a borehole adjacent to the current course of the river Chelmer during the replacement of the existing A138 Chelmer Viaduct and river bridge allowed the palaeoenvironmental analysis and radiocarbon dating of floodplain sediments. The results of which demonstrated that woodland clearance and possible exploitation of the valley floor were occurring by early Bronze Age, despite a lack of archaeological evidence for settlement at this time. The nearby sites of Springfield Lyons and Great Baddow demonstrate a lack of human activity in this period although unexcavated cropmark evidence from within the wider valley may yet demonstrate the presence of earlier human activity. This study demonstrates the potential of the Chelmer valley to preserve palaeoenvironmental records and potentially for the preservation of archaeological sites in the floodplain deposits.

A Late Prehistoric Timber Alignment in the Waveney Valley, Suffolk: Excavations at Barsham Marshes

Abstract This paper describes the results of excavations and associated palaeoenvironmental analyses at Barsham Marshes, Suffolk, England. The site is a triple post alignment of oak stakes built at the edge of a palaeochannel of the River Waveney. The alignment has been traced for over 30 m but neither terminus of the site has been excavated. Dendrochronological dating of the timbers has produced a range of felling dates between 8 BC and AD 8 indicating a late Iron Age date for the structure. No other cultural material was recovered. Palaeoenvironmental analyses of the associated deposits indicate that the site was located at the edge of a shallow channel of the River Waveney with local aquatic and alder carr vegetation and evidence for more open scrub and pastoral environments in the wider landscape. This channel appears to have infilled by the 11th century AD and is overlain by a thin layer of humified peat, corresponding to the uppermost level of preservation of the stakes. It is likely that any superstructure originally supported by the stakes had finally decomposed or been dismantled by this time. The site is compared to that of Beccles some 3 km down river where excavations have revealed a triple post alignment also dating to the late Iron Age but with evidence for activity during the Romano-British period. The possible form and function(s) of the sites are discussed.