image/svg+xml183XI/2/2020INTERDISCIPLINARIA ARCHAEOLOGICANATURAL SCIENCES IN ARCHAEOLOGYhomepage: http://www.iansa.euGeophysical Survey of the Hillfort Staré Zámky near Brno-Líšeň, Czech RepublicPeter Miloª*, Tomáš Tencerª, Michal Vágnerª, Michaela Prišťákováª, Igor MurínªaInstitute of Archaeology and Museology, Faculty of Arts, Masaryk University, Arna Nováka 1, 602 00 Brno, Czech Republic1. IntroductionThis article discusses the results of geophysical surveys carried out at the archaeological site of Staré zámky near Brno-Líšeň, Czech Republic. The research, undertaken within the framework of the project “Early Medieval hillforts in the light of non-destructive investigation”, as the name suggests, aims to extend our knowledge about Central European Early Medieval fortifed sites using a wide range of non-invasive prospection methods. The main task was to answer questions related to the layout of the features inside the hillforts and their immediate surroundings, as well as the extent and density of inhabitation and the nature of the fortifcation systems. Staré zámky proved to be a suitable example site to demonstrate the contribution of various geophysical prospecting methods in gaining new knowledge about an area that has been already intensively archaeologically excavated in the past.2. The site and its contextThe poly-cultural site “Staré zámky” is located approximately 1.5 km to the northeast of the centre of Brno-Líšeň suburb. It is situated on a prominent rocky promontory formed by conglomerates, oriented with its longer axis in a northwest to southeast direction. Approximately in the middle of the promontory there is a narrow, approximately 30 m wide, neck. From here, the promontory extends towards the southeast into an irregular isosceles triangle with a total area of approximately 4 ha. The northern, eastern and southern sides of the promontory are bordered by steep, partly-rocky hillsides (elevation approximately 60 m), which are wrapped around by a small watercourse called “Říčka”. From the western side, the promontory is bounded by a steep ravine that rises towards the northwest before becoming a gently-sloping plateau.The oldest traces of settlement can be dated back to the Neolithic period. However, archaeological excavations failed to identify a single settlement feature from this period. Signifcantly more-intensive settlement came with Volume XI ● Issue 2/2020 ● Pages 183–195*Corresponding author. E-mail: milop@post.skARTICLE INFOArticle history:Received: 7thMay 2020Accepted: 13thOctober 2020DOI: words:Early Medieval Periodhillfortnon-destructive methodsmagnetometryground-penetrating radarelectrical resistivity tomographyABSTRACTThe aim of this paper is to present the results of geophysical surveys at the Staré zámky site near Brno-Líšeň, which were carried out in 2019. Electrical resistivity tomography, georadar survey and large-scale magnetic prospection were all carried out there. The primary task of the frst two methods was to investigate the inner structure of the still-existing ramparts and to identify their individual structural elements. The magnetic survey focused on the identifcation of areas where potential archaeological features can be found – together with the identifcation of previously-unknown fortifcations. The surveys were successful: we have found numerous settlement features from diferent phases of settlement, an early medieval cemetery and fortifcations of various types, sizes and state of preservation. The results of previous archaeological research of the site played an important role for interpretation of the geophysical data. Together these results provide important insights into the study of the complex fortifed settlement of Staré zámky. Despite our results, some questions which cannot be answered by geophysical research alone remain unanswered.
image/svg+xmlIANSA 2020 ● XI/2 ● 183–195Peter Milo, Tomáš Tencer, Michal Vágner, Michaela Prišťáková, Igor Murín: Geophysical Survey of the Hillfort Staré Zámky near Brno-Líšeň, Czech Republic184the Eneolithic period. At that time, there was a settlement protected by a rampart and ditch (Medunová-Benešová, 1964). Further traces of settlement have been found from the Bronze and Iron Ages, as well as from the Roman and Migration periods.The largest growth in settlement came during the Early Medieval Period. The oldest evidence of the Early Medieval settlement comes from the 7thto 8thcentury, when in addition to the material fnds, several housing features and remains of fortifcations in the form of a wooden palisade have been found (Procházka, 2009, pp.152–157; Staňa, 1972, pp.111–114). The large area (approximately 4 ha) of the promontory was surrounded by a wood-earth structure with a frontal stone wall in the 9thcentury (Procházka, 2009, pp.152–159; Staňa 1972, pp.115–117). Its remains are still preserved on the northern and eastern side of the promontory, which can be described as the acropolis of the hillfort. Behind the narrow neck of land to the northwest of the acropolis was a bailey (“Bailey I”), which was approximately 1 ha in size and triangular in shape. From the northwest it was surrounded by a rampart, possibly of a stone structure, but the perimeter of the promontory was apparently not protected (Procházka, 2009, p.157; Staňa, 1972, p.136). Further to the northwest there stood another bailey (“Bailey II”), which was fortifed by a massive earthen rampart with a ditch on the north-western side. The preserved rampart itself is over 300 metres long. In the south, it emerges from the forest to a feld where it has been ploughed up, but it continues in the form of an indistinct terrain wave towards the present-day Líšeň cemetery, where its further course then becomes problematic (Procházka, 2009, p.157; Staňa, 2000, p.201). The size of Bailey II is not clear to us, but according to the known facts and confguration of the terrain, we estimate it to be approximately 10 ha.Associated with the existence of an Early Medieval hillfort, there was are also a large number of archaeologically-recorded residential features excavated, both habitable and economic (Staňa, 1972; 2000, p.201). In the north-western part of the acropolis it is considered that there was a fenced area, which Staňa (1972, p.139) describes as a magnate court. Within Bailey II, part of a skeletal burial ground (dated to the 9thcentury) has been uncovered (Poulík, 1948–1950, pp.103–104). At the turn of the 10thcentury, the fortifed settlement was hit by a large fre, which may be associated with a violent invasion (Staňa, 1972, p.154; 2000, p.201). Sometime at the beginning of the 10thcentury, shortly after the demise of the hillfort, a smaller fortifed settlement was built at the acropolis area. Subsequently, during the 10th century, a short “hiatus” in settlement (Kalčík, 2013), or a period of only sparse settlement of the site has been predicted (Procházka et al., 2011, p.497; Staňa, 1972, pp.157–158; 2000, pp.203–206). During the second half of the 11thcentury, settlement of the site started to decline (Kalčík, 2013, pp.234–235; 2015, p.193).3. Archaeological excavation and geophysical research of the hillfortThe Staré zámky site was archaeologically intensively investigated in the past. In 1863, several human skeletons and archaeological artifacts were found during ploughing. In 1890–91, a local archaeologist, Martin Kříž, conducted the frst excavation on the site. A total of 40 detection pits, two 124-metre-long probes and several cuts through the rampart were carried out (Poulík, 1960, p.132). During 1948–49, under the leadership of Josef Poulík, Bailey I and the neck of land between Bailey I and the acropolis of the hillfort was excavated. In total, an area of approximately 2250 m² was uncovered. A part of the 9thcentury skeleton burial ground was also excavated (Poulík, 1949). Between 1953 and 1965, the most extensive stage of excavation so far was carried out, uncovering an area of 5250 m². On the promontory of the hillfort, excavation cuts on the perimeter wall. The excavation also uncovered the remains of prehistoric and Early Medieval settlement in the form of housing features, ditches and the rest of two routes dated to the Bronze Age and Early Medieval period (Benešová, Staňa, 1959, pp.166–174). Since then, no archaeological excavation has been carried out on this site. However, recently, the number of fndings obtained with the help of metal detectors originating from the area of the hillfort, or its immediate vicinity, has substantially increased (e.g.Vachůt et al., 2013).More than half a century has passed since the last excavations were conducted on the site. The fndings were partially processed, and the old research has been reviewed and summarized (Kalčík, 2013; 2015), but no new information has been added that could broaden our knowledge. The geophysical survey planned for this site in 2019 was to erase this shortfall. Given the curtailed possibilities for archaeological methodology, such as the limited size of the surveyed area, or the costly and time-consuming excavation of the fortifcations, the use of geophysics was justifable. A geophysical survey enables the identifcation of subsurface structures of an archaeological nature in a relatively short time. Moreover, as it is non-destructive, it leaves the site under investigation intact for further research in the future.The aim of the geophysical measurements at Staré zámky was to broaden our knowledge of the intensity and character of the settlement, as well as the fortifcation system of the hillfort. Electrical resistivity tomography (ERT) and georadar (GPR) survey were carried out, focusing on the preserved remains of the hillfort’s fortifcation elements – the ramparts and ditches. There was also a magnetic feld survey, which focused on the accessible area in the acropolis and both bailies.The role of ERT and GPR prospection was to identify the internal structure of the rampart fortifcations, or to focus on the identifcation of adjacent ditches and determination of their potential extent and depth. A visual survey identifed the two most suitable places. The frst one was located on the eastern edge of the acropolis and the second in the northern part of the outer rampart of Bailey II (Figure 1).
image/svg+xmlIANSA 2020 ● XI/2 ● 183–195Peter Milo, Tomáš Tencer, Michal Vágner, Michaela Prišťáková, Igor Murín: Geophysical Survey of the Hillfort Staré Zámky near Brno-Líšeň, Czech Republic185For the purpose of georadar surveying, a X3M Ramac georadar (Geoscience AB Malå), with two shielded antennae with a central frequency of 250 and 500 MHz, was used. On the eastern edge of the acropolis, due to the dense vegetation, only a single profle approximately 18 m in size was measured. On the outer rampart of Bailey II only one 46 m long profle was measured, the surveyed area being 4×30 m. The spacing between the individual measurement lines was 0.5 m (Figure 1). GPR data collected throughout the area were evaluated using ArchaeoFusion software (University of Arkansas), Easy 3D software (Geoscience AB Malå) and GPR Slice software (Geophysical Archaeometry Laboratory). Horizontal time/depth cuts were exported in raster form (JPEG) to ArcGIS (ESRI), where they were georeferenced, interpreted and the identifed anomalies further digitized into a vector plan. Vertical time/depth cuts were processed using RadExplorer software (v. 1.42; Geoscience AB Malå) and vectorized in Adobe Illustrator CS6.The ERT prospection was performed using the ARES 850W apparatus (GF Instruments Brno). At the eastern edge of the acropolis a 26-metre-long profle was measured. On the outer rampart of Bailey II, a 47-metre-long profle was measured (Figure 1). Three types of confgurations were used – Wenner, Schlumberger and dipole–dipole. RES2DINV software (GEOTOMO, Malaysia) was used for data processing, where both the extreme values were removed, and the apparent resistivity values were inverted to the actual resistivity values. Topographic correction was applied to the resulting data and the resulting model was created showing the real distribution of the specifc electrical resistivity in the given profle.Magnetometry is the most suitable geophysical method for resolving issues related to settlement activities, as it is able to explore large areas in a small amount of time and at the same time identify a wide range of archaeological structures. The total area investigated at the Staré zámky hillfort reached 12.01 ha (acropolis: 3.36 ha; Bailey I: 0.81 ha; Bailey II: 6.87 ha; area outside of fortifcation: 0.97 ha; Figure 1). The survey was carried out with a fuxgate magnetometer LEA MAX (Eastern Atlas, Germany). The instrument is designed as a gradiometer. Due to the fat terrain it was possible to use ATV mode (the instrument was pulled by a quad). Ten fuxgate probes (FEREX CON 650, Foerster, Germany) confgured 0.5 metres apart were used for the measurements. The density of the magnetic measurements was 0.5 m on the X axis and 0.1 m on the Y axis (measurement direction). The measured data were collected together along with spatial information from the GNSS receiver – Trimble R-10 model 2 (Trimble, USA). Measurement data were processed using the standard procedure in LEAD2 program. The magnetic feld intensity map (magnetogram) in nanoTesla (nT) units was then smoothed by averaging. ArcGIS Desktop 10.7 (ESRI) software was used to present and interpret the results.