Geophysical and Geochemical Studies on Historical Layers in the Area of Old Krakow, Poland

TLDR: In this article, the authors used electrical resistivity tomography (ERT) and ground penetrating radar (GPR) to locate a small fragment of the historical water system, and to determine the type and stratigraphy of the sediments filling it.

Abstract: In the present study, application of complementary to each other non-invasive geophysical methods and geochemical slim hole drilling allowed to locate a small fragment of the historical water system, and to determine the type and stratigraphy of the sediments filling it. The most universal, and frequently used geophysical methods are electrical resistivity tomography (ERT) and ground penetrating radar (GPR). These methods are characterized by high precision mapping of the investigated medium, and the possibility of implementation even in small areas. They play an important role in defining the location of archaeological excavations sites. The applied geophysical methods enabled precise and comprehensive analyses of near-surface zones in the area of Planty Park in Krakow (Poland), such as engineering/geological recognition, and detection of anthropogenic structures. As an important metropolis of Central Europe in the medieval period, Krakow due to rapid development of craft and trade had a high demand for water both for the general population and craftsmen. As a result, the city continuously developed and used a complex watercourse and sewage collection system. The layout of the system has not yet been accurately mapped. The authors decided that the ERT method was suitable for this case study. The study was conducted in the eastern part of Planty Park, near Dominikanska Street, measurements were taken using a two-dimensional (2D) parallel layout of ERT profiles. The authors also carried out a three-dimensional (3D) image interpretation process. Even though the ERT method is limited by the requirement of a minimal implementation area, it makes the detection of former watercourses possible. In order to verify the ERT results, three small-diameter mechanical holes drillings were carried for purpose of macroscopic analysis of the ground type with determination of its lithology and layer layout. On gathered samples laboratory measurements of pH, oxidation–reduction potential Eh, and conductivity EC were done. Copyright © 2016 John Wiley & Sons, Ltd.