Envir1 Alfred's Way, Barking: Palaeoenvironmental Assessmentonmental Sampling at 1 Alfred's Way, Barking, London. Palaeoenvironmental Assessment Report

Wessex Archaeology was commissioned by Lok'n Store Limited to undertake a palaeoenvironmental assessment of sub-samples taken during a purposive geoarchaeological borehole survey of c. 0.6 hectares of land at 1 Alfred's Way, Barking, London Borough of Barking and Dagenham. This Site is centred on National Grid Reference 546400, 183600 (TQ 4640 8360) This report follows on from a purposive borehole survey, which identified a series of superficial deposits comprised Pleistocene sands and gravels, overlain by a Holocene alluvial sequence of minerogenic alluvium, organic alluvium and peat. The Pleistocene sands and gravels likely corresponded to the East Tilbury Marshes and/or Mucking Gravels to the north, and Shepperton Gravels in the south. Within borehole WA01, a fine-grained clay unit was encountered within the gravel sequence and was identified as high geoarchaeological potential. The series of organic alluvium and peat deposits have a high geoarchaeological potential to provide information of the environment and vegetation history during deposition, and to contain in situ archaeology. A programme of targeted palaeoenvironmental assessment and scientific dating was recommended on boreholes WA01 and WA04. The principal aim of the palaeoenvironmental assessment is to determine the age, nature and depositional history of deposits recovered at the Site. The results will be used to assess the preservation potential of palaeoenvironmental remains, and to reconstruct past environments and landscapes change associated with local and regional archaeological records and settlement histories. The results will inform on the need for and scope of further analysis, where appropriate Radiocarbon dating of the peat places the deposition of the lowermost organic alluvium in the Early Neolithic (3425-3375 cal. BC), with peat formation spanning from the Middle Neolithic (3325-3250 cal. BC) to the Early/Middle Bronze Age (1615-1535 cal. BC). OSL dating of fine-grained deposits within the river terrace deposits to the north of the Site produced A date of 411�30 thousand years ago (Kya). However, the De values associated with this date are higher than the highest independently verified date, which suggests that there may have been reworking of older sediments, resulting in an older date. Within the fine-grained sediments within the terrace sequence, preservation of pollen was poor, with a high number of reworked grains, while diatoms and foraminifera/ostracods were absent. This poor preservation and concentration likely reflect aerobic conditions during deposition, allowing for microbial activity, and post-depositional activities, such as high water acidity/alkalinity. Within the lower organic alluvium, pollen and plant macroremains had good preservation and concentrations, likely reflecting anaerobic conditions of deposition. Within the peat preservation of plant macroremains and pollen was good, but diatom preservation was poor. This likely reflects aerobic conditions resulting in good preservation of pollen, but post-depositional conditions, such as high water alkalinity/acidity resulting in damage to diatom frustules. The sands and gravels across the Site represent two terraces, based on the elevation ranges, with the terrace subject to palaeoenvironmental assessment likely being the East Tilbury Marshes, deposited during Marine Isotope Stages 4-2. The fine-grained deposit may represent a warm-stage interglacial (MIS 3), as alder is present. However, pollen concentrations were very low, and this interpretation is tentative. Organic deposition occurred from the Early Neolithic to the Early/Middle Bronze Age, which is consistent with many peat deposits within the Thames Floodplain sequence. During the deposition of the early peat, the wetland environment would have been an alder carr environment with a sedge understory, with the dryland comprised of mixed deciduous woodland.