Geoarchaeology: the underlying framework for environmental studies

By Matt Canti

BoguckinewGeoarchaeology commonly provides the underlying framework for environmental studies, reflecting the way that soils and sediments contain the artefacts and ecofacts from which we deduce past environments. In these types of study, the headline ecological interpretation is usually derived from pollen, snails or insects and the study of the sediments must necessarily take a background position. If we look at Thornbush and Desloges (2011), for example, high quality core descriptions and closely spaced sediment samples, each with particle size, organic matter and calcium carbonate determinations provided both the basis for, and some assistance with, interpretations from palynological and malacological studies. Similarly, the preliminary study of the Cetina Valley in Croatia by Smith et al. (2006) scoped the potential for pollen and insect analyses taken from a number of different borehole transects. More recently, Bogucki et al. (2012) have carried out a large multi-proxy study involving sedimentology, palynology, malacology and cladoceran analysis to provide environmental details complementing existing archaeological investigations at Oslonki, Poland. Their results not only produced classic vegetational and landscape interpretations, but also highlighted the clearance-led erosion of exposed soils near the Neolithic settlements, producing windblown sand lenses in the gyttja accumulations (see right).

BottarinewMore rarely, geoarchaeological analysis is the central basis for interpretation or prediction, and some very interesting papers of this type have appeared in EA over the last few years. Bottari et al. (2009) used a mix of archaeological, historical, sea-level and geomorphic analyses to try and pinpoint the lost harbour of ancient Tindari – Sicily’s dominant town of the North east coast in the Greek and Roman periods (see attached figure “Bottari Fig 3”). As well as the effects of sea-level changes, marine and fluvial action were shown to have caused progradation of the shoreline, infilling the lowland areas, and partly burying ancient buildings. The palaeotopographic reconstruction of the Oliveri coastal plain and Tindari Cape helped identify the location for a possible 4th century BC landing place southeast of the Cape, suitably protected from prevailing winds.

Brown et al. (2009) carried out a survey of the coombes on the south side of Exmoor, UK., and found one (Anstey’s Coombe) that contained anomalously deep infill deposits showing OSL dates grouped predominantly into Romano-British period and to the 16th – 17th centuries. The catchment of this coombe included a deep trench of the type that is commonly found where iron ore mining has taken place (see right), and the authors concluded that deposition of mine waste was the likely mechanism for producing the high volumes of sediment. This raises the possibility of predicting and ultimately locating mining activity sites by catchment surveys.

WardLarcombeTaking the idea of geomorphological prediction a step further into the unknown, Ward and Larcombe (2008) presented a very thorough investigation of the preservation potential of contexts at the bottom of the southern North Sea. The area was drowned between 6 and 12 K BP during the post-glacial sea level rise, and therefore has enormous potential for preservation of Palaeolithic and Mesolthic archaeology. The development pressure on the area, both from wind-farms and from dredging, contrasts strongly with our limited knowledge of its stratigraphy and the immense difficulty of any investigation. The authors successfully brought together the existing knowledge of the topography, geology and anthropogenic impact to date, in order to provide a rational basis for future planning.

Bogucki, Peter, Nalepka, Dorota, Grygiel, Ryszard & Nowaczyk, Bolesław  (2012) Multiproxy environmental archaeology of Neolithic settlements at Osłonki, Poland, 5500‐4000 BC. Environmental Archaeology 17(1), 45-65.

Bottari, Carla, D’Amico, Maria, Maugeri, Monica, Bottari, Antonio, D’Addezio, Giuliana, Privitera, Biagio & Tigano, Gabriella (2009) Location of the ancient Tindari harbour from geoarchaeological investigations (NE Sicily). Environmental Archaeology 14(1), 37-49.

Brown, Antony, Bennett, Jenny & Rhodes, Edward (2009) Roman mining on Exmoor: a geomorphological approach at Anstey’s Combe, Dulverton. Environmental Archaeology 14(1), 50-61.

Smith, David, Gaffney, Vince, Grossman, Darja, Howard, Andy J., Milošević, Ante, Ostir, Krištof, Podobnikar, Tomaš, Smith, Wendy, Tetlow, Emma, Tingle, Martin & Tinsley, Heather (2006) Assessing the later prehistoric environmental archaeology and landscape development of the Cetina Valley, Croatia. Environmental Archaeology 11(2), 171-186.

Thornbush, Mary J., Desloges, Joseph R. (2011) Palaeoenvironmental reconstruction at an oxbow lake situated at the lower Nottawasaga River, southern Ontario, Canada.  Environmental Archaeology 16(1), 1-15.

Ward, Ingrid & Larcombe, Piers (2008) Determining the preservation rating of submerged archaeology in the post-glacial southern North Sea: a first-order geomorphological approach. Environmental Archaeology 13(1), 59-83.