![Page 1: 1Hannu Luodes 18.9.2007 Natural stone assessment with ground penetrating radar (GPR) The 15th Meeting of the Association of European Geological Societies](https://reader035.vdocuments.us/reader035/viewer/2022062804/56649ee75503460f94bf8172/html5/thumbnails/1.jpg)
1Hannu Luodes 18.9.2007
Natural stone assessment with ground penetrating radar (GPR)
The 15th Meeting of the Association of European Geological Societies
16–20 September 2007
Tallinn, Estonia
![Page 2: 1Hannu Luodes 18.9.2007 Natural stone assessment with ground penetrating radar (GPR) The 15th Meeting of the Association of European Geological Societies](https://reader035.vdocuments.us/reader035/viewer/2022062804/56649ee75503460f94bf8172/html5/thumbnails/2.jpg)
2Hannu Luodes, 18.9.2007
Natural stone assessment with ground penetrating radar (GPR)
Location of the study areas
![Page 3: 1Hannu Luodes 18.9.2007 Natural stone assessment with ground penetrating radar (GPR) The 15th Meeting of the Association of European Geological Societies](https://reader035.vdocuments.us/reader035/viewer/2022062804/56649ee75503460f94bf8172/html5/thumbnails/3.jpg)
3Hannu Luodes, 18.9.2007
Natural stone assessment with ground penetrating radar (GPR)
The ground penetrating radar instrumentation• GSSI SIR 2000 control unit
• Antennae between 40 MHz and 400 MHz
Control unit200 MHz antenna
![Page 4: 1Hannu Luodes 18.9.2007 Natural stone assessment with ground penetrating radar (GPR) The 15th Meeting of the Association of European Geological Societies](https://reader035.vdocuments.us/reader035/viewer/2022062804/56649ee75503460f94bf8172/html5/thumbnails/4.jpg)
4Hannu Luodes, 18.9.2007
Natural stone assessment with ground penetrating radar (GPR)
Study area 1
• Porphyritic granite situated in the south-eastern Finland • It belongs to the Central Finland granitoid complex and is described
postkinematic in relation to the deformation of the area
![Page 5: 1Hannu Luodes 18.9.2007 Natural stone assessment with ground penetrating radar (GPR) The 15th Meeting of the Association of European Geological Societies](https://reader035.vdocuments.us/reader035/viewer/2022062804/56649ee75503460f94bf8172/html5/thumbnails/5.jpg)
5Hannu Luodes, 18.9.2007
Natural stone assessment with ground penetrating radar (GPR)
Study area 1
![Page 6: 1Hannu Luodes 18.9.2007 Natural stone assessment with ground penetrating radar (GPR) The 15th Meeting of the Association of European Geological Societies](https://reader035.vdocuments.us/reader035/viewer/2022062804/56649ee75503460f94bf8172/html5/thumbnails/6.jpg)
6Hannu Luodes, 18.9.2007
Natural stone assessment with ground penetrating radar (GPR)
Study area 1
Typical feature of the rock is a strong horizontal exfoliation type fracturing (height of the bench about 5 m)
![Page 7: 1Hannu Luodes 18.9.2007 Natural stone assessment with ground penetrating radar (GPR) The 15th Meeting of the Association of European Geological Societies](https://reader035.vdocuments.us/reader035/viewer/2022062804/56649ee75503460f94bf8172/html5/thumbnails/7.jpg)
7Hannu Luodes, 18.9.2007
Natural stone assessment with ground penetrating radar (GPR)
Study area 1
• GPR measurement traverse of 65 m in length (vertical and horizontal scale are equal)• The profile was corrected with altitude data to present the actual surface and fractures
orientation
![Page 8: 1Hannu Luodes 18.9.2007 Natural stone assessment with ground penetrating radar (GPR) The 15th Meeting of the Association of European Geological Societies](https://reader035.vdocuments.us/reader035/viewer/2022062804/56649ee75503460f94bf8172/html5/thumbnails/8.jpg)
8Hannu Luodes, 18.9.2007
Natural stone assessment with ground penetrating radar (GPR)
Study area 1
• The GPR was able to detect the major horizontal and sub-horizontal fracturing
![Page 9: 1Hannu Luodes 18.9.2007 Natural stone assessment with ground penetrating radar (GPR) The 15th Meeting of the Association of European Geological Societies](https://reader035.vdocuments.us/reader035/viewer/2022062804/56649ee75503460f94bf8172/html5/thumbnails/9.jpg)
9Hannu Luodes, 18.9.2007
Natural stone assessment with ground penetrating radar (GPR)
Study area 1
• Vertical or near vertical fractures were difficult to detect due to their small reflection surface towards the measuring antenna
![Page 10: 1Hannu Luodes 18.9.2007 Natural stone assessment with ground penetrating radar (GPR) The 15th Meeting of the Association of European Geological Societies](https://reader035.vdocuments.us/reader035/viewer/2022062804/56649ee75503460f94bf8172/html5/thumbnails/10.jpg)
10Hannu Luodes, 18.9.2007
Natural stone assessment with ground penetrating radar (GPR)
Study area 1
• The horizontal fractures near the surface were sometimes strongly weathered providing space for surface water to collect
• Those spots were detected as individual targets on the radar measurement profile
• The spots can be thought to be reflections from a sub-horizontal fracture zone near the surface
![Page 11: 1Hannu Luodes 18.9.2007 Natural stone assessment with ground penetrating radar (GPR) The 15th Meeting of the Association of European Geological Societies](https://reader035.vdocuments.us/reader035/viewer/2022062804/56649ee75503460f94bf8172/html5/thumbnails/11.jpg)
11Hannu Luodes, 18.9.2007
Natural stone assessment with ground penetrating radar (GPR)
Study area 2
Soapstone situated in North KareliaIt belongs to an Archaean greenstone belt, in the border zone between the Archaean area and the Palaeoproterozoic North Karelian Schist Belt
![Page 12: 1Hannu Luodes 18.9.2007 Natural stone assessment with ground penetrating radar (GPR) The 15th Meeting of the Association of European Geological Societies](https://reader035.vdocuments.us/reader035/viewer/2022062804/56649ee75503460f94bf8172/html5/thumbnails/12.jpg)
12Hannu Luodes, 18.9.2007
Natural stone assessment with ground penetrating radar (GPR)
Study area 2
Typical North Karelian soapstoneSample size 260 mm x 200 mm
![Page 13: 1Hannu Luodes 18.9.2007 Natural stone assessment with ground penetrating radar (GPR) The 15th Meeting of the Association of European Geological Societies](https://reader035.vdocuments.us/reader035/viewer/2022062804/56649ee75503460f94bf8172/html5/thumbnails/13.jpg)
13Hannu Luodes, 18.9.2007
Natural stone assessment with ground penetrating radar (GPR)
Study area 2
Soapstone quarry in North Karelia
![Page 14: 1Hannu Luodes 18.9.2007 Natural stone assessment with ground penetrating radar (GPR) The 15th Meeting of the Association of European Geological Societies](https://reader035.vdocuments.us/reader035/viewer/2022062804/56649ee75503460f94bf8172/html5/thumbnails/14.jpg)
14Hannu Luodes, 18.9.2007
Natural stone assessment with ground penetrating radar (GPR)
Study area 2
• With the soapstone, the measurements revealed more of the internal structure of the rock, making the detection of the fracturing complex
• Especially internal lineation was quite well visible in those sections where the stone contained more conductive minerals.
![Page 15: 1Hannu Luodes 18.9.2007 Natural stone assessment with ground penetrating radar (GPR) The 15th Meeting of the Association of European Geological Societies](https://reader035.vdocuments.us/reader035/viewer/2022062804/56649ee75503460f94bf8172/html5/thumbnails/15.jpg)
15Hannu Luodes, 18.9.2007
Natural stone assessment with ground penetrating radar (GPR)
Study area 2
• Large open horizontal fractures were detectable also in this stone type, which can be helpful in planning of the quarrying operations.
![Page 16: 1Hannu Luodes 18.9.2007 Natural stone assessment with ground penetrating radar (GPR) The 15th Meeting of the Association of European Geological Societies](https://reader035.vdocuments.us/reader035/viewer/2022062804/56649ee75503460f94bf8172/html5/thumbnails/16.jpg)
16Hannu Luodes, 18.9.2007
Natural stone assessment with ground penetrating radar (GPR)
Conclusions
• Ground penetrating radar (GPR) is suitable for large-scale quality assessment of natural stone deposits and quarries
• The measurements are easy and quick to do and the preliminary results can be evaluated immediately
• The fracture detection level varies depending on the used equipment, mainly on the frequency
• The development in GPS technology has made it possible to position the measurements accurately and thus trace back the results into the quarry to help extraction planning
• The differences in the measurement results and their interpretation found among these two rock types indicate the importance of knowing the electromagnetic properties and mineralogy of the stone
• Also knowing the geological structure and other characteristics of the stone beforehand helps to avoid false interpretations