Geometry of Quaternary sediments along the north Norfolk coast, UK: a shallow seismic study

Seismic refraction profiles on land and marine single-channel seismic profi ling in inshore waters were used to supplement shallow-borehole data to det ermine the overall form of the Quaternary sequence in the coastal zone of N orth Norfolk. Refraction data from five principal profiles across the zone shows four velocity units, and correlation with the borehole data indicates that these (principally) represent (a) the surface drained/weathered zone, (b) Holocene and glacial sediments, (c) weathered chalk, and (d) fresh cha lk. A strong reflection on two marine profiles is interpreted as the top of the Chalk. Integration of the data shows that Quaternary sediments are con tained in a broad, shallow, east-west trending trough centred along the mar shes, landward of barrier sediments. This trough extends eastwards beyond t he present shoreline into the southern North Sea. The linearity of the axis of the trough and the adjacent coastline suggests an underlying structural control that may be east-west faulting on the northern side of the London- Brabant Massif.