Forecasting weathering and rock erosion through rock surface hardness: A case study on the Avşa Island granite formations
Abstract
Rock erosion and its severity are directly proportional to the severity weathering. Erosion develops rapidly and effectively in rocks where the weathering is severe. The variations in the rock surface hardness values are indication of the weathering level of rocks. Rock surface hardness values tend to decrease on the weathered rocks. Rock surface hardness itself can be measured and classified easily using a Schmidt hammer.
The purpose of this study is to asses and analyse the rock hardness across Avşa Island (in the Marmara Sea, Turkey) using the Schmidt hammer methodology.
Rock surface hardness measurements were made on Avşa Island granites at 100 different locations using the Schmidt hammer. A statistical analysis of the measurement data was carried out followed by field controls of the new data obtained from the analysis. The results were used to create a rock surface hardness classification for Avşa Island, and were also assessed as indicators of weathering rate and erosion potential.
This new classification indicates that Avşa Island's Granite rocks can be segmented into 3 basic groups. 40% of the granites are "Hard", without serious weathering and resistant to erosion. The second group, represents 10% of the of Avşa Island's granite and is classified as "Medium to Weak". The remaining 50% Group 3 granites in the Avşa Island fall into the "Very weak" class. Group 3 granites are rocks deformed by weathering, and have high erosion potential.
Keywords
Rock surface hardness,weathering,Rock erosion,Granite weathering,Schmidt hammer
Kaynakça
- Aoki, H. & Matsukura, Y. (2007) A new technique for non-destructive field measurement of rock-surface strength: an application of the Equotip hardness tester to weathering studies. Earth Surface Processes and Landforms, 32/ 12: 1759–1769, DOI: 10.1002/esp.1492. Augustinus, P.C. (1992) Rock resistance to erosion: some further considerations. Earth Surface Processes and Landforms, 16: 563-569. Aydin, A. ve Basu, A. (2005) The Schmidt Hammer in rock material characterization. Engineering Geology, 41: 1211-1214.
- Aydın, A. (2008) ISRM Suggested Method for Determination of the Schmidt Hammer Rebound Hardness: Revised Version. R. Ulusay (Ed.), The ISRM Suggested Methods for Rock Characterization, Testing and Monitoring: 2007–2014: 25-33. DOI: 10.1007/978-3-319-07713-0.
- Basu, A. & Aydın, A.A. (2004) Method for normalization of Schmidt hammer rebound values. International Journal of Rock Mechanics & Mining Sciences, 41:1211-1214.
- Colman, S.M. (1981) Rock-weathering rates as functions of time. Quaternary Research, 15: 250-264
- Day, M.J. (1980) Rock hardness: field assessment and geomorphic importance. Professional Geographer, 32: 72-81.
- Day, M.J. (2010) Rock hardness: field assessment and geomorphic importance. The Professional Geographer, 32:1, 72-81, DOI: 10.1111/j.0033-0124.1980.00072.x
- Day, M.J. & Goudie, A.S. (1977) Field assessment of rock hardness using the Schmidt test hammer. BGRG Technical Bulletin, 18: 19-29.
- Ericson, K. (2004) Geomorphological surfaces of different age and origin in granite landscapes: an evaluation of the Schmidt hammer test. Earth Surface Processes and Landforms, Volume 29, Issue 4, Pages 495–509, DOI: 10.1002/esp.1048, http://onlinelibrary.wiley.com/doi/10.1002/esp.1048/full
- Hall, K., Thorn, C., Sumner, P. (2012) On the persistence of ‘weathering’. Geomorphology, 149–150: 1–10.
- Huggett, R.J. (2011) Fundamentals of Geomorphology, Third Edition. Routledge, 270 Madison Avenue, New York, NY 10016, ISBN 0-203-86008-X Master e-book ISBN.