Environmental and sea-level changes in London from 10 500 BP to the present: A case study from Silvertown

Abstract

Results of stratigraphic and palaeoecological studies carried out on deposits at Silvertown in east London are discussed in relation to current models of Late glacial and Holocene alterations to river form, relative sea-level change, vegetation development and archaeology in the lower Thames. The data indicate that the braided bedform typical of British cold stage rivers evolved into a lower energy meandering form around 10 500 BP, a process that caused channel cut-off. The fill of one of these contained organic sediments and in-washed sands dating from 10 500-9300 BP in which there was palynological evidence for the replacement of Late Devensiaan tundra by early Holocene pine forest. Biostratigraphic evidence for the period 9000-5500 BP was limited owing to the absence of organic sediments and, instead, deposition was of in-channel sands. Peat formation began at c. 5500 BP, and these organic sequences contain evidence of the elm decline at 5010±70 BP and the lime decline at 3070±60 BP. The latter event was accompanied by forest clearance for Bronze Age agriculture and a consequent alteration to both the marsh and dry ground flora. Around 2500 BP the peats were submerged beneath estuarine muds as a result of further sea-level rise. A series of age/altitude points relating to Holocene sea-levels were constructed from the site data and were found to fit relatively well with current ideas of sea-level change in the post-glacial period. The results from Silvertown reflect data from shorter sequences in the London area, combining evidence of the Late glacial to early Holocene transition, with information on river development, changes in sea-level tendency and human-induced vegetation change.