Petra Schneidhofer

Abstract

The successful application of archaeological geophysical prospection (AGP) towards the investigation of archaeological landscapes depends on an encompassing understanding of the palaeoenvironmental settings of the study area.  On a general methodological level, this dependency concerns survey design and geoarchaeological evaluation of survey outcome. In order to fully understand the development of archaeological landscapes, however, it is necessary to incorporate palaeoenvironmental data as an important component into the interpretation of archaeological features.

Environments are not stable but dynamic systems that change over time formed by a wide variety of interrelated factors, processes and characteristics involving weather, climate, soils and sediments, as well as geomorphological, ecological, and hydrological factors and past and present human activities (Grotzinger et al. 2008). Palaeoenvironmental reconstruction currently is based mainly on coring and test trenching in order to gain information on and access to underlying soils, sediments and geology. This methodology results in two-dimensional, largely interpolated data sets - a serious limitation for the understanding of palaeoenvironments as three-dimensional dynamic systems.

During the last two decades, archaeological geophysical data acquisition has advanced remarkably in terms of speed and resolution allowing for the first time extensive 3D multi-method approaches (Linford 2006, Leckebusch 2003) and hence the archaeological prospection of entire landscapes (Trinks 2011). Distinct archaeological features thereby form only a small part of large-scale, high resolution AGP data sets; the majority of geophysical data is often devoid of (visible) archaeological data. Nevertheless, these empty areas contain valuable information regarding pedological, sedimentological, palaeohydrological and geological processes. Consequently, such processes result in and are displayed as continuous (e.g. stratification) as well as distinct palaeoenvironmental features (e.g. geological outcrops, old river systems or former wetlands) exhibiting different electric and magnetic properties, which respond to the various geophysical measurement systems.

Commonly, AGP studies pay little attention to anomalies or features not interpreted as archaeology and rarely mention or investigate them within the scope of archaeological survey projects. Studies in geology, sedimentology and geoarchaeology concerned with the reconstruction of palaeoenvironments have repeatedly used geophysical techniques such as seismics, ground penetrating radar and resistivity (Bristow et al. 2000, Neal et al. 2002). However, spatial coverage is limited to few isolated profiles and resolution remains mostly low in favor of penetration depth. More importantly, visualization and interpretation of the geophysical data are not exploiting the three-dimensionality of data sets.

Large scale, high resolution AGP data sets, in contrast, certainly show potential for palaeoenvironmental reconstruction (Dalan & Bevan 2002); to what extent, however, is yet unexplored. Arising questions include type and resolution of palaeoenvironmental data available as well as evaluation of the actual contribution towards the understanding of archaeological landscapes.

Consequently, this project will investigate the potential of large scale, high resolution AGP data for the reconstruction of palaeoenvironments. The study will specifically review the significance and use of palaeoenvironmental data in AGP and test the use of AGP data for the identification and interpretation of continuous and distinct features relevant to the reconstruction of the palaeoenvironment. Additionally, the study will compare and correlate physical properties of sediments and soils with magnetic and electric properties derived from AGP surveys in order to develop future approaches to use large scale, high resolution AGP data for the reconstruction of palaeoenvironment.

The project is structured in seven successive research stages based on AGP data of two selected case studies in Norway and Austria prospected by both magnetometry and ground penetrating radar. The case study in Gokstad (http://www.khm.uio.no/english/visit-us/viking-ship-museum/exhibitions/gokstad/) will thereby act as a pilot study in order to initially test the proposed work flow and methodology. Based on these first insights, the study area of Halbturn (Daim & Doneus 2004) will be used to solve upcoming flaws in work flow and further refine the developing methodology. The structure is framed by a theoretical section at the beginning providing research rationale and current state-of‐the‐art within AGP regarding the analysis and implementation of data for palaeoenvironmental reconstruction. The final chapter has evolutional character and primarily aims at the iterative impact on the archaeological interpretation and the initial survey design.

Bibliography

Bristow, C.S., P.N. Chroston, S.D. Bailey. 2000. The structure and development of fordunes on a locally prograding coast: insights from ground penetrating radar surveys, Norfolk, UK, Sedimentology 47: 923-944.

Dalan, R. A., B. W. Bevan. 2002. Geophysical indicators of culturally emplaced soils and sediments, Geoarchaeology: An international Journal 17(8): 779-810.

Daim, F., N. Doneus (ed.). 2004. Halbturn I, das kaiserzeitliche Gräberfeld und die Villa von Halbturn, Burgenland, naturräumliche Voraussetzungen, Prospektion und Vorbericht, Monographien zur Frühgeschichte und Mittelalterarchäologie, Innsbruck: Universitätsverlag Wagner.

Grotzinger, J., T.H. Jordan, F. Press, R. Siever. 2008. Allgemeine Geologie (5th ed.), Berlin: Spektrum Akademischer Verlag.

Leckebusch, J. 2003. Ground-penetrating radar, a modern three-dimensional prospection method, Archaeological Prospection 10: 213-240.

Linford, N. 2006. The application of geophysical methods to archaeological prospection, Reports on Progress in Physics 69: 2205-2257.

Neal, A., N.I. Pontee, K. Pye, J. Richards. 2002. Internal structure of mixed-sand-and-gravel beach deposits revealed using ground-penetrating radar, Sedimentology 49, 789–804

Trinks, I. 20011. The new Ludwig Boltzmann institute for archaeological prospection and virtual archaeology, ISAP News 26: 9-11.