A rapid rise in relative sea level ~9-7 cal ka bp along the SW Cumbria coast, NW England
Along the macro‐tidal (10.7 m tide range) SW Cumbria coast in situ rooted tree stumps are infrequently exposed below present‐day low Spring Tide elevations (≤−4.5 m OD). To date these remnants, we conducted a salvage operation at two sites on in situ rooted tree stumps exposed below the lowest tide levels; these sites are no longer exposed. We obtained four radiocarbon dates on these tree remnants and reference an earlier site recovered in 1972. One wood sample was identified as Quercus robur or Q. petraea, while samples from Haverigg and Kirby‐in‐Furness are tree Salix spp. The median group age for the rising relative sea level (RSL) that killed the trees was 8602±243bp cal a BP with an estimated Mean Tide Level (MTL) of ~≤−9 m. Evidence indicates that RSL rose ~10 m along this section of coast at a rate of between of between 18.5 and 8.7 mm a–1 until ~6800 cal a BP, or earlier, before the rate of global sea level rise fell below that of the local glacial isostatic recovery. The transgression is coeval with rapid collapse and deglaciation of the Laurentide Ice Sheet in Hudson's Bay and slightly lags the global Meltwater Pulse‐1C.