Predictive modelling of multiperiod geoarchaeological resources at a river confluence: a case study from the Trent-Soar, UK

This research project developed a terrace sequence model of alluvial landscape development to aid the management of the geoarchaeological resource within a temperate valley floor threatened by aggregate extraction. The model was created using the remote sensing techniques of light detection and ranging (lidar) and ground-penetrating radar (GPR), dovetailed with other archaeological and geological data sets within a geographical information system (GIS). Lidar first pulse (FP), last pulse (LP) and intensity models were used in a combination of ways to characterize the landscape. The topographic LP model was particularly effective at defining the major alluvial landforms, such as the higher terraces and palaeochannels. Lidar intensity data defined the palaeochannels, in response to the surface sediments' ability to absorb/reflect the lidar laser pulse. The three-dimensional architecture of the sediments infilling the valley floor was elucidated and modelled by GPR survey along geospatially referenced transect lines. These surveys had their time-slices calibrated through gouge coring along the transect lines, allowing depth slicing of the sediment stratigraphy. The GPR surveys accurately defined the depth of silty clay alluvium overlying the sands and gravels. Internal structure was revealed within the terrace gravels and at the margins of palaeochannels, allowing identification of bounding surfaces and construction of relative landform chronologies. However, GPR penetration into fine-grained palaeochannel fills was generally shallow, with little internal channel stratigraphy revealed. The lidar data sets and the GPR depth slices were integrated within ArcGIS and ArcScene. The distribution of the known and sometimes visible archaeological remains is considered in context of the geomorphology. It is demonstrated that erosion and sedimentation have 'geologically filtered' the archaeological resource and that some areas that have previously been considered archaeologically barren have high potential for both cultural and environmental archaeological remains. Copyright (c) 2006 John Wiley & Sons, Ltd.