GPR investigations at the Castle of Monteagudo

Summary

Ground-penetrating radar (GPR) investigations were efficiently conducted at the Andalusian Castle of Monteagudo archaeological site to detect potential archaeological remains within the castle grounds. The objects identified were mainly connected to former structures of the castle.

Site description

The investigation site is located on a plateau outside the main castle construction. The soils consist of anthropic fill, of various thickness, on top of undulating quartzite and salte rocks. The investigation covered an area of 7×50 meters on the plateau.

PROJECT

Method: Ground Penetrating Radar (GPR)
Solution: MALÅ GX GPR system with a 450 MHz antenna
Measurement: 5 cm trace interval and 150 ns time window.
Software for processing and interpretation: Reflex2DQuick and Object Mapper 2018

The investigation area on the Castle of Monteagudo

The measured GPR profiles are marked in green, an area of 7x50m

Solution

It was decided to use GPR as the primary method to map potential subsurface objects, as GPR allows for rapid – non-destructive – investigation of large surfaces. The ability to detect smaller objects with GPR is also advantageous.

The GPR investigations were carried out as a mesh of profiles, spaced 1 meter apart, laid out across the 7×50 meter investigation area.

Results & Conclusions

It turned out that the maximum depth of investigation was limited to around 2.5 meters, due to the top layer of filling material, which turned out to be quite conductive. Nevertheless, numerous objects, likely remnants of structures, were identified and mapped within the investigated plateau.

Most of the identified objects were found at a depth of 1 to 2 meters, although locally some anomalies were also detected at depths of 2 to 2.5 meters.

The locations of these anomalies were marked on a map, revealing predominantly straight lines, some of which coincided with the positions of the towers along the upper castle wall.

The MALÅ GX450 GPR system was used for the archaeological investigation

Example of a radargram. Some hyperbolas, indicating objects, can be identified in the upper 2 meters. Due to the conductive filling in the top layer the depth penetration was quite limited

Acknowledgement

We like to thank Basalto Informes Técnicos SL (www.basaltoit.com) for sharing the information above. Basalto Informes Técnicos SL was established in 1996 and is based in Murcia, Spain. The company specializes in geology and related fields, including geotechnics, geophysics, hydrology, environmental studies, archaeology, and mining.

Basalto Informes Técnicos SL utilizes various techniques, including geophysics, to address soil and ground-related technical challenges for clients in architecture and engineering, real estate development, construction, waste management, agriculture, and public administration sectors.