Abstract
Physical properties (Schmidt hammer in situ rock strength; degree of weathering; orientation, spacing, width and continuity of joints, bedding planes and faults; groundwater flow) of bedrock-incised rills and gullies were ecamined at selected localities in southern Africa. The resulting data was compared to froms of erosion observed in the field to test for possible influences of rock physical properties on rill and gully development. Bedrock-incised rill erosion occurs at low RMS (Rock Mass Strength) values (40–50). Rills generally do not form where RMS values are high (> 50). Though V-shaped bedrock-incised gullies form in lithologies with a wide range of RMS values (40–69), these values exert strong control on longitudinal morphometry. Future studies should concentrate on establishing a database on properties of erosion forms to aid identification of lithological conditions (e. g. deep regolith) which are potentially susceptible to accelerated erosion.
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References
Beckedahl, H. R.: Rock mass strength determinations as an aid to landscape interpretation. In: Gardiner, V. (ed.), International Geomorphology, Part I, pp. 393–406, John Wiley & Son Ltd., Chichester 1987.
Beckedahl, H. R.; Dardis, G. F.: The role of artificial drainage in the development of soil pipes and gullies: Some examples from Transkei, southern Africa. In: Dardis, G. F.: Moon, B. P. (eds.), Geomorphological studies in southern Africa, pp. 229–245, A. A. Balkema, Rotterdam 1988.
Bowyer-Bower, T. A. S.; Bryan, R. B.: Rill initiation: Concepts and experimental evaluation on badland slopes. Zeitschrift für Geomorphologie 60, 161–175 (1986)
Bryan, R. B.: Processes and significance of rill development. In: Bryan, R. B. (ed.), Rill erosion, Catena Supplement 8, 1–15 (1987)
Bryan, R. B.; Yair, A.: Perspectives on studies of badland geomorphology. In: Bryan, R. B.; Yair, A. (eds.), Badland geomorphology and piping, pp. 1–12, GeoBooks, Norwich 1982.
Dardis, G. F.: Quaternary erosion and sedimentation in badland areas of southern Africa. In: Yair, A.; Berkowicz, S. (eds.), Arid and semi-arid environments: Geomorphological and pedological aspects. Catena Supplement 14, 1–9 (1990)
Dardis, G. F.; Beckedahl, H. R.: Gully formation in Archaean rocks at Saddleback Pass, Barberton Mountain Land, South Africa. In: Dardis, G. F.; Moon, B. P. (eds.), Geomorphological studies in southern Africa, pp. 285–297, A. A. Balkema, Rotterdam 1988.
Dardis, G. F.; Beckedahl, H. R.; Bowyer-Bower, T. A. S.; Hanvey, P. M.: Soil erosion forms in southern Africa. In: Dardis, G. F.; Moon, B. P. (eds.), Geomorphological studies in southern Africa, pp. 187–214, A. A. Balkema, Rotterdam 1988.
Day, M. J.: Rock hardness: field assessment and geomorphic importance. Professional Geographer 32, 72–81 (1980)
Day, M. J.; Goudie, A. S.: Field assessment of rock hardness using the Schmidt test hammer, BGRG Technical Bulletin 18, 19–29 (1977)
Ford, D. C.; Lundberg, J.: A review of dissolutional rills in limestone and other soluble rocks. In: Bryan, R. B. (ed.), Rill erosion, Catena Supplement 8, 119–140 (1987)
Gerits, J.; Imeson, A. C.; Verstraten, J. M.; Bryan, R. B.: Rill development and badland regolith properties. In: Bryan, R. B. (ed.), Rill erosion, Catena Supplement 8, 141–160 (1987)
Hall, K. J.: The physical properties of quartz-micaschist and their application to freeze-thaw studies in the maritime Antarctic. Earth Surface Processes and Landforms 12, 137–149 (1987)
Hobday, D. K.: Fluvial deposits of the Ecca and Beaufort Groups in the eastern Karoo Basin, Southern Africa. In: Miall, A. D. (ed.), Fluvial Sedimentology, pp. 413–430 Canadian Society of Petroleum Geologists Memoir 5, 1978.
Hodges, W. K.; Bryan, R. B.: The influence of material behaviour on runoff generation in the Dinosaur badlands, Canada. In: Bryan, R. B.; Yair, A. (eds.), Badland geomorphology and piping, pp. 13–46, GeoBooks, Norwich 1982.
Hooker, R. M.: Gully (donga) erosion in Swaziland — A distributional analysis. Unpublished manuscript 1984.
Imeson, A. C.; Kwaad, F. J. P. M.; Verstraten, J. M.: The relationship of soil physical and chemical properties to the development of badlands in Morocco. In: Bryan, R. B.; Yair, A. (eds.), Badland geomorphology and piping, pp. 47–70, GeoBooks, Norwich 1982.
Lageat, Y.; Robb, L. J.: The relationships between structural landforms, erosion surfaces and the geology of the Archaean granite basement in the Barberton region, eastern Transvaal. Transactions, Geological Society of South Africa 87, 141–159 (1984)
Moon, B. P.: Refinement of a technique for determining rock mass strength for geomorphological purposes. Earth Surface Processes and Landforms 9, 189–193 (1984)
Olivier, H. J.: Karoo mudrock. In: Brink, A. B. A. (ed.), Engineering geology of southern Africa, Volume 3: The Karoo Sequence, pp. 57–106, Building Publications, Pretoria 1983.
Poesen, J.: Transport of rock fragments by rill flow — A field study. In: Bryan, R. B. (ed.), Rill erosion, Catena Supplement 8, 35–54 (1987)
Selby, M. J.: A rock mass strength classification for geomorphic purposes, with tests from Antarctica and New Zealand, Zeitschrift für Geomorphologie 24, 31–51 (1980)
Selby, M. J.: Rock mass strength and the form of some inselbergs in the central Namib Desert. Earth Surface Processes and Landforms 7, 489–497 (1982)
Turner, B. R.: Tectonic and climatic controls on continental depositional facies in the Karoo Basin of Northern Natal, South Africa. Sedimentary Geology 46, 231–257 (1986)
Watson, A.; Price-Williams, D.; Goudie, A. S.: The palaeoenvironmental interpretation of colluvial sediments and palaeosols of the late Pleistocene Hypothermal in Southern Africa. Palaeoclimatology, Palaeogeography, Palaeoecology 45, 225–249 (1984)
Williams, R. B. G.; Robinson, D. A.: The effect of surface texture on the determination of the surface hardness of rock using the Schmidt hammer. Earth Surface Processes and Landforms 8, 289–292 (1983)
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Dardis, G.F., Beckedahl, H.R. The role of rock properties in the development of bedrock-incised rills and gullies: Examples from Southern Africa. GeoJournal 23, 35–40 (1991). https://doi.org/10.1007/BF00204407
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DOI: https://doi.org/10.1007/BF00204407