Geoarchaeology, the four dimensional (4D) fluvial matrix and climatic causality A.G. Brown School of Geography, The University of Southampton, Highfields, Southampton, SO17 1BJ, UK ABSTRACT ARTICLE INFO Article history: Received 5 September 2007 Received in revised form 10 March 2008 Accepted 13 March 2008 Available online 27 May 2008 Keywords: Geoarchaeology Sediment geometry Evolutionary geoarchaeology Climate change Scale dependency Abrupt climate change Geoarchaeology is the application of geological and geomorphological techniques to archaeology and the study of the interactions of hominins with the natural environment at a variety of temporal and spatial scales. Geoarchaeology in the UK over the last twenty years has flourished largely because it has gone beyond technological and scientific applications. Over the same period our ability to reconstruct the 3-dimensional stratigraphy of fluvial deposits and the matrix of fluvial sites has increased dramatically because of a number of technological advances. These have included the use of LiDAR (laser imaging) and radar to produce high- resolution digital surface models, the use of geophysics, particularly ground penetrating radar and electrical resistivity, to produce sediment depth models, and the use of GIS and data visualisation techniques to manipulate and display the data. These techniques along with more systematic and detailed sedimento- logical recording of exposed sections have allowed the construction of more precise 3-dimensional (volumetric) models of the matrix of artefacts within fluvial deposits. Additionally a revolution in dating techniques, particularly direct sediment dating by luminescence methods, has enabled the creation of 4-dimensional models of the creation and preservation of these sites. These 4-dimensional models have the ability to provide far more information about the processes of site creation, preservation and even destruction, and also allow the integration of these processes with independent data sources concerning cultural evolution and climatic change. All improvements in the precision of dating fluvial deposits have archaeological importance in our need to translate events from a sequential or geological timeframe to human timescales. This allows geoarchaeology to make a more direct contribution to cultural history through the recognition of agency at the individual or group level. This data can then form a component of biocomplexity or agent-based modelling which is becoming increasingly used in the natural sciences, particularly ecology and geomorphology and which can be used to test scenarios including the impact on, and response of, hominins to abrupt or catastrophic environmental change. Whilst catastrophic events clearly represent the atypical they can be illuminating in revealing cognitive processes resulting in abandonment, coping, mitigation and innovation. These points are exemplified using two in-depth case studies: one from the Holocene geoarchaeological record of the River Trent in Central England and the other from the Palaeolithic record from rivers in South West Britain. In the former the interaction between climate change and human activity is illustrated at the year to century timescale whilst in the other the timescale is millennial. These case studies have deliberately been chosen to be as different as possible in temporal and spatial scale with the aim of examining the applicability of methodological and theoretical aspects of geoarchaeology. Lastly the paper considers the problem of scale in geoarchaeology and concludes it is process-dependency, which ultimately affects the questions we can ask, and that questions of human response to climate change are fundamentally a product of materiality and cognitive processes. This demands an in-depth contextual approach to such questions rather than database-driven assertions of causality. © 2008 Elsevier B.V. All rights reserved. 1. Introduction This paper takes as its starting point the view that geoarchaeology is more than just the application of geological methods to archaeology. This view is not always made explicit because of the methodological bias of most of the standard texts (French, 2003; Herz and Garrison, 2004; Rapp and Hill, 2006; Goldberg and McPhail, 2006) but was explicit in the ecological approach of probably the most influential volume by Butzer (1982). Geoarchaeology is, or should be, concerned with the interaction of hominins (from individuals to groups), with their natural environment and its perturbations over the Pleistocene and Holocene and it holds much in common with the broader field of environmental archaeology (Brown, 1997a,b; Dincauze, 2000). This and similar broad definitions of geoarchaeology have enabled geoarchaeology to add considerable depth to our understanding human–environment relations in the fluvial, coastal and colluvial Geomorphology 101 (2008) 278–297 E-mail address: Tony.Brown@soton.ac.uk. 0169-555X/$ – see front matter © 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.geomorph.2008.05.021 Contents lists available at ScienceDirect Geomorphology journal homepage: www.elsevier.com/locate/geomorph