The process of geological
mapping requires integrating a number of field techniques. On this page
an overview is given on how some of these techniques have been applied in
the Boxgrove Raised Beach Mapping Project.
1.
Familiarity with local topography and landforms can be a useful guide to
what may be present below the ground. Here, in Halnaker Park, the ruined
Manor was sited on the top of a low rise, elevated from the lower, flatter
land to the south. This break in slope coincides exactly with the position
of the fossil cliff cline. It can be traced, as a landform, for much of
the length of the raised beach.
3.
Where overlying sediment depths made trial pitting impossible, boreholing
was used to log the distribution of each stratigraphic unit. Boreholing
was carried out using a 5m Dando Rig geared to cut a 150mm hole. Boreholing
is a low-impact method of investigation, leaving only a small re-turfed
area of disturbance.
4. Gravels and loose,
unconsolidated, sand were sampled directly from the cutting as bulk samples.
Where the fine-grained, archaeologically sensitive deposits of the Slindon
Formation were encountered, U100 samples were taken. These recovered 450mm
lengths of intact, uncontaminated sediment sheathed in 100mm wide piping.
U100 samples are subsequently split, with one half being logged and sub-sampled
and the other half stored as part of our sediment archive.
