Krošinskių Manor GPR Survey

Abstract

Ground penetrating radar (GPR) surveys were conducted at the former Krošinskių Manor, located in Rokiškis, Lithuania, searching for remnants of the manor complex. The manor belonged to the Krošinskių family, who ruled the Rokiškis area for 200 years, dating back to the 16th century. Due to modern development and a lack of resto-ration resources, many of the manor’s past structures are no longer standing, and their locations are left unknown. Earlier structures include defensive fortifications, servant quarters, a sauna, and a mill. In the search for the missing buildings, two GPR grids were collected at the site using a Sensors and Software pulseEKKO GPR system with 500 MHz antennae, with 0.25 m line spacing. Both GPR grids were processed using GFP_Edit, EKKO_Project, and GPR Slice. The first GPR grid measured 9.5 m x 32 m, resulting in 38 lines, and the second grid measured 27 m in width, resulting in 108 lines collected at various lengths. The results of the GPR survey will provide local Lithuanian archaeologists with important data that will aid in future excavations, as well as provide the citizens of Rokiškis a better understanding of a prominent historical site in their community.Slice View image taken at 0.60 meters in depth showing a Rectan-gular feature that may indicate the existence  of an a prior defensive fortification.Line View (line 53) showing the potential fortification.Slice View image collected in Grid 2 at a depth of 0.25 meters highlighting the linear feature of low reflectance. The current Rokiškis Regional Museum

Introduction

The history of the Krošinskių Manor in Rokiškis, Lithuania dates back to the 17th century with the Krošinskių family. The Krošinskių family ruled the region for two centuries and holds an important historical role in the region (Deksnys). Since that time the manor has under-gone many different transforma-tions as different families had taken possession of the manor and built new structures. The Tyzenhauz family for example, came into possession of manor in 18th century and built a brew-ery that still stands today (Deksnys).

Map Displaying the location of the Manor in Rokiškis, Lithuania.

Due to the historical importance of this site, a ground penetrating radar (GPR) survey was conducted in the summer of 2018. This survey was comprised of two GPR grids. These grids were collected to the east and west of the standing brewery. The grids were collected over the course of two days using a pul-seEKKO GPR system equipped with 500 MHz antenna. The results of this survey show the potential existence of human disturbance in the subsurface as well as potential buried structures from past eras of the manor.

The brewery as it stands today.

Ground Penetrating Radar

GPR is a geophysical tool that allows for the subsurface to be imaged. Pulses of electromag-netic energy are sent into the ground where the electromagnetic waves of energy are reflected back to the sensor (Jol and Bristow, 2003). Areas of different dielectric properties cause the radar pulse to reflect back to the sensor (Davis and Annan, 1989). The sensor then records these reflections in units of time (ns) where the velocity of the electromagnetic waves can then be calculated. With velocity calculated, depth of features in the subsurface can be measured (Jol and Bristow, 2003).

Satellite image showing the location of the location of the two grids collected in the survey

Collection of Grid 1 using the pulseEKKO GPR System from Sensors and Software.

Collection of Grid 2 (500 MHz). The remnants of the brewery can be seen in the background.

Workflow

Once the lines were collected, the lines were brought into GFP_Edit. GFP_Edit allows for the GPR lines to be orientated correctly in the format of a grid. Once the lines were placed into their respective grid formats. The grids were then brought into EK-KO_Project were the lines could be processed and interpreted. EKKO_Project allows for grids and indi-vidual lines to be visualized both horizontally (Line View) and vertically (Slice View). To aid in the visu-alization of the data, processed Slice View grid data was brought into Voxler 3 where 3D models of the data could be created.

Results

When viewing the results in Grid 1, there are several horizontal and semi-horizontal features that appear in the Slice View image as well as the 3D model. There are anomalies are also found within the horizontal profiles in the form of hyperbolic and dipping reflections. These reflections are consistent with past archaeological GPR studies (Bevan, 2006).

SliceView image collected in Grid 1 at a depth of 0.60 meters. The areas in red show areas if relativley higher amplitude than the surronding areas.

3D model created using an ISO field in Voxler 3, highlighting the reflectors found in SliceView.

Line View image (line 10) hyperbolic reflections can be seen at the 12 meter mark as well as dipping reflectors found at the 8 meter and the 29 meter marks. These reflectors may indicate past structures from the manor.

Line View image (line 26) was collected at the 6.5 meter mark within Grid 1. There are linear and hyperbolic reflectors found throughout the profile. These reflectors can be seen at the 2 meter, 12 meter, 20 meter and the 28 meter mark.

Results from Grid 2 show a rectangular anomaly created by a series of strong reflectors interpreted as a former defensive structure. Also, an area of low reflectance is located within the grid that may be a result of past fortifications at the manor.

Line View (line 53) showing a potential fortification.

Conclusions

Using a pulse_EKKO GPR system equipped with a 500 MHz an-tenna, we collected two grids at the Krošinskių Manor as part of our GPR survey. The results of the survey show the evidence of linear features in the subsurface with strong hyperbolic reflections. These features may indicate the presence of past structures of the Krošinskių Manor. The findings of this study will be valuable to archaeologists in future work at the site by providing them mapped areas of interest for future excavations.

The current Rokiškis Regional Museum

Acknowledgments

We would like to give thanks for the Student Blugold Commitment funds through the University of Wisconsin-Eau Claire Student-Faculty International Fellows Program for Research, Service, and Creative Activity, the Student Blugold Commitment Differential Tuition funds through the University of Wisconsin-Eau Claire Student/Faculty Research Collaboration Program (Office of Research and Sponsored Programs), and the Student Blugold Commitment Differential Tuition funds through the University of Wisconsin-Eau Claire Summer Research Experiences for Undergraduates Program (Office of Research and Sponsored Programs). We would like to acknowledge the Maurice Greenberg Center for Judaic Studies at The University of Hartford, the Rokiškis Regional Museum, and the University of Wisconsin-Eau Claire Printing Services. We would also like to thank Dr. Harry Jol and Dr. Richard Freund for all of their support.

Sources

Davis, J.L. and Annan, A.P., 1989. Ground Penetrating Radar for High- Resolution Mapping of Soil and Rock Stratigraphy,

    Geophysical Prospecting, 37: 5, 31–551.

Deksnys, B., The tree of the Košinskis family: https://www.muziejusrokiskyje.lt/kunigaiksciai-krosinskiai (acessed October 

       2018)

Jol, H.M., and Bristow, C.S., 2003, GPR in sediments: advice on data collection, basic processing and interpretation, a good 

    practice guide, Jol, H.M. and Bristow, C.S., eds., Ground Penetrating Radar in Sediments: London, Geological Society, 

    Special Publication 211, p. 9-27.