Combined Electrical Resistivity Tomography (ERT), Direct-Push Electrical Conductivity (DP-EC) Logging and Coring - A New Methodological Approach in Geoarchaeological Research

Non-invasive geophysical methods have been increasingly applied in geoarchaeological research commonly showing the need of data calibration based on stratigraphical information deduced from outcrops or sediment cores. In this contribution, a methodological approach combining two-dimensional (2D) electrical resistivity tomography (ERT) and stratigraphical data based on coring and, for the first time in geoarchaeological research, direct-push electrical conductivity (DP-EC) logging is presented and discussed. The approach yields high resolution data based on studies of two different types of archives, the Holsterburg site in central Germany located in a fluvio-terrestrial zone and the Corfu City site in Greece located in a near-coastal zone. It is shown that DP-EC logs trace fluctuations over grain size in high resolution which reflect changes of depositional conditions in the course of time. In addition, constraints from DP-EC logs in the form of layer interfaces and electrical resistivities were incorporated into the ERT inversion process minimizing the ambiguity of inversion results. It is shown that incorporating regions with certain starting resistivities based on DP-EC logs exceed the advantage of using layer interfaces alone. It is concluded that in future geoarchaeological and geomorphological studies a combined application of coring, DP-EC logging and ERT measurements should be considered as a standard approach towards a more comprehensive stratigraphical characterization of the shallow subsurface. Copyright (c) 2016 John Wiley & Sons, Ltd.