Marine Aggregate Licence Area 522: Stage 1 and 2 Geoarchaeological Assessment

In May 2016, 30 vibrocores were collected from the Marine Aggregate Licence Area 522, located c. 6km south of The Needles on the western end of the Isle of Wight. A desk based geoarchaeological assessment (Stage 1) was made of geotechnical descriptions, which identified that most cores contained sands and gravels overlying the Lower Cretaceous Wealden (Wessex) Formation. A visual assessment of the core photographs and geological logs (Stage 1 assessment) has identified a series of Late Pleistocene / Early Holocene deposits associated with palaeochannels and the wider floodplain area preserved within Area 522, including a number of cores with organic preservation towards the base of the vibrocore sequences above the underlying Wealden Formation geology. Potential palaeosols also appear preserved within a number of cores, likely associated with wetland soil developments, indicating the preservation of a palaeo-landsurfaces. Two cores were selected for geoarchaeological recording (Stage 2 assessment), which confirmed the presence of peats associated with palaeochannels to the west of Area 522, along with an underlying palaeosol preserved beneath the peat that is attributed to a hydric (wetland) soil profile. The peat in VC 27 was found to have good plant macrofossil preservation including visible seeds preserved. These deposits are anticipated to be Early Holocene. These vibrocores are considered as having the geoarchaeological potential to better understand the submerged palaeolandscape of this area of the English Channel and the submerged palaeo-Stour-Avon river catchment. The geoarchaeological assessment of the 30 vibrocores from Area 522, collected in 2016, has shown a range of palaeochannel and floodplain deposits (Unit 2) of geoarchaeological interest. In two cores, VC27 and 30, peat deposits are identified. These fine-grained and organic deposits would constitute a contaminant to the resource sediments that would be actively avoided during the dredging operations. In addition, the industry standard mitigation of leaving a capping layer at the base of the resource will minimise disturbance of the fine-grained deposits (ABPmer 2019). Vibrocores VC 27 and VC 30 were selected for geoarchaeological recording (Stage 2), confirming the presence of a semi-terrestrial sequence probably associated with wetland palaeosol formation followed by alluvial / lagoonal sediment deposition during the Late Pleistocene / Early Holocene when sea levels were lower. The vibrocores, accompanied with the marine geophysics showing the presence of a series of palaeochannel areas, demonstrates the high geoarchaeological potential of this area to not only understand the submerged palaeolandscape of this area of the English Channel but also the potential for the recovery of in situ prehistoric archaeology from these areas.