During excavations for new bridge piers in salt marshes at Widnes, oak timbers and red deer bones were found overlying glacial clay at the bottom of the estuary sediment 11 m below the current land surface. RSK principal archaeologist Laurence Hayes and RSK archaeology team leader Andy Towle took the samples with assistance from the Merseylink site and environmental management teams. Subsamples were sent for dendrochronological analysis (tree ring dating) before being submitted for radiocarbon dating. The timbers were radiocarbon dated to the Late Mesolithic period (approximately 4500–4200 BC). A large oak tree trunk found 2 m higher up in the sediment was dated to the Late Neolithic period (approximately 2800–2500 BC).
The findings open a window on a submerged post-glacial landscape. Before the gradually rising sea level inundated the Mersey Valley at the end of the last ice age, the landscape would have been mixed deciduous woodland and home to red deer and other animals, and a hunting ground for the local hunter-gatherer populations whose footprints can still be found eroding out of the coastal sand dunes at Hightown and Formby. Over the following millennia, the estuary sediment has accumulated to a depth of about 11 m, thereby sealing and permanently waterlogging these fragile organic remains in perfect condition.
Red deer bone
RSK is supporting the Mersey Gateway project with archaeological, geotechnical, soils testing and remediation expertise.
For more information, please contact Laurence Hayes.