Volume 8, Issue 5, October 2019, Page: 277-284
An Alternative Structural Model for the Development of the Cape Fold Belt Syntaxis and Groundwater Potential
Blignault Hendrik Johan, Independent Researcher
Theron Johannes Nicolaas, Department of Earth Sciences, University of Stellenbosch, Stellenbosch, South Africa
Received: Sep. 11, 2019;       Accepted: Oct. 7, 2019;       Published: Oct. 25, 2019
DOI: 10.11648/j.earth.20190805.13      View  27      Downloads  14
Abstract
The syntaxis separates the eastern and western branches of the Cape Fold Belt, South Africa. A satisfactory and holistic solution remains unresolved. This investigation is to develop an alternative hypothesis for the development of the syntaxis. Because macroscopic fold structures are considered most relevant in resolving a tectonic solution on subcontinental scale, the fold hinge traces of macroscopic structures were comprehensively compiled from published geological maps. The fold patterns of the eastern and western fold belt branches are separated across the hypothetical Ceres lineament without any identified interaction. The en echelon fold pattern of the western branch is interpreted as the result of northern movement of a lower crustal block. The eastern branch is dominated by north-verging over folding and thrusting in the east and westwards towards the Ceres lineament the folds are predominantly upright. It is suggested that differential basal slip causes the fold belt to terminate against the lineament with a sinistral rotation that is also accommodated by the sinistral Villiersdorp ductile shear zone. It appears that basal slip retardation increases from east to west. The two fold belt branches were developed in adjacent crustal blocks that reacted differently to northward tectonic transport driven by subduction and accretion further south along southern Gondwana. The hypothesis is testifiable. The structural investigation revealed the hitherto unknown existence of special structural situations with wellfield potential for groundwater that remains to be tested by drilling.
Keywords
Cape Fold Belt, Syntaxis, Structural Kinematics, Groundwater Wellfield
To cite this article
Blignault Hendrik Johan, Theron Johannes Nicolaas, An Alternative Structural Model for the Development of the Cape Fold Belt Syntaxis and Groundwater Potential, Earth Sciences. Vol. 8, No. 5, 2019, pp. 277-284. doi: 10.11648/j.earth.20190805.13
Copyright
Copyright © 2019 Authors retain the copyright of this article.
This article is an open access article distributed under the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Reference
[1]
De Villiers J., 1944. A review of the Cape Orogeny. Annals of the University of Stellenbosch, Vol. XXII, Sect. A, Nos. 1–14, pp 183-208.
[2]
De Villiers J., 1956. Die drie sintaksisse in die Suidwestelike Kaapprovinsie. Tegnikon, Oktober 1956, 13 pp.
[3]
Newton, A. R., 1973. A gravity folding model for the Cape Fold Belt. Transactions of the Geological Society of South Africa, 76, pp. 145-152.
[4]
Cobbold, P. R., Gapais, D., Milani, E. J., Rosello, E. R., and Szatmari, P., 1992. Permo-Triassic intracontinental deformation in SW Gondwana. In: De Wit, M. J. and Ransome, I. G. D. (Eds), 1992. Inversion Tectonics of the Cape Fold Belt, Karoo and Cretaceous basins of Southern Africa. Balkema Rotterdam.
[5]
Söhnge, A. P. G., 1983. The Cape Fold Belt Perspective, pp 1-6. In: Söhnge, A. P. G. and Hälbich. I. W., 1983 (Eds.). Geodynamics of the Cape Fold Belt. Special Publication No. 12, The Geological Society of South Africa.
[6]
Ransome, I. G. D. and De Wit. M. J., 1992. Preliminary investigations into a microplate model for the South Western Cape, pp 257–266. In: De Wit, M. J. and Ransome, I. G. D. (Eds), 1992. Inversion Tectonics of the Cape Fold Belt, Karoo and Cretaceous basins of Southern Africa. Balkema Rotterdam.
[7]
De Beer, C. H., 1995. Fold interference from simultaneous shortening in different directions: the Cape Fold Belt syntaxis. Journal of African Earth Sciences, Vol. 21, No. 1, pp. 157-169.
[8]
De Beer, C. H., 1998. Structure of the Cape Fold Belt in the Ceres arc. Council for Geoscience, Bulletin 123, 93 pp.
[9]
Johnston, S. T., 2000. The Cape Fold Belt and Syntaxis and the rotated Falkland Islands: dextral transpressional tectonics along the southwest margin of Gondwana. Journal of African Earth Sciences, 31, pp. 51-63.
[10]
Booth, P. W. K., 2011. Stratigraphic, structural and tectonic enigmas associated with the Cape Fold Belt: challenges for future research. South African Journal of Geology, 114, pp 235-248.
[11]
De Wit, M. J. and Ransome, I. G. D., 1992. Regional inversion tectonics along the southern margin of Gondwana. In: De Wit, M. J. and Ransome, I. G. D. (Eds), 1992. Inversion Tectonics of the Cape Fold Belt, Karoo and Cretaceous basins of Southern Africa. Balkema Rotterdam.
[12]
Marshak, S., 1988. Kinematics of orocline and arc formation in thin-skinned orogens. Tectonics, 7, pp 73-86.
[13]
Scheepers, R., 1995. Geology, geochemistry and petrogenesis of Late Precambrian S-, I- and A-type granitoids in the Saldania belt, Western Cape Province, South Africa. Journal of African Earth Sciences, 21, pp 35-58.
[14]
Qiuesnel, Y., Weckmann, U., Ritter, O., Stankiewicz, J., Lesur, V., Mandea, M., Langlais, B,. Sotin, C. and Galdeano, A., 2009. Simple models for the Beattie Magnetic Anomaly in South Africa. Tectonophysics 478, pp 111-118.
[15]
Hartnady, C. J. H., Newton A. R. and Theron J. N., 1974. The stratigraphy and structure of the Malmesbury Group in the southwestern Cape. Bull. Precambrian Research Unit, University Of Cape Town, 15, 193-213.
[16]
Kisters, A. F. M., Belcher, R., W., Scheepers, R., Rozendaal, A., Jordaan, L. S., Armstrong, R., A., 2002. Timing and kinematics of the Colenso Fault: The Early Paleozoic Shift from collisional to extensional tectonics in the Pan-African Saldania Belt, South Africa. South African Journal of Geology, 105, pp 257-270.
[17]
Visser, H. N. and Theron, J. N., 1973. Map 3218 Clanwilliam, Geological Survey, Dept. of Mines.
[18]
Blignault, H. J., and Theron, J. N., 2015. The facies association tillite, boulder beds, boulder pavements, liquefaction structures and deformed drainage channels in the Permo-Carboniferous Dwyka Group, Elandsvlei area, South Africa. South African Journal of Geology, 118, pp 157-172.
[19]
Gresse, P. G. and Theron, J. N., 1992. The geology of the Worcester area. Explanation of sheet 3319. Geological Survey, Department of Mineral and Energy Affairs, 79 pp.
[20]
Theron, J. N., Gresse, P. G., Siegfried, H. P. and Rogers, J., 1992. The Geology of the Cape Town area, Explanation Sheet 3318, Geological Survey, Department of Mineral and Energy Affairs, 140 pp.
[21]
Wilcox, R. E., Harding, T. P. and Seely, D. R., 1973. Basic Wrench Tectonics. American Association of Petroleum Geologists Bulletin, 57, 74-96.
[22]
Sylvester, A. G., 1988. Strike-slip faults. Geol. Soc. of America Bull., 100, 1666-1703.
[23]
Hälbich, I. W., 1992. The Cape Fold Belt Orogeny: State of the art 1970’s-1980’s, pp. 141-158. In: De Wit, M. J. and Ransome, I. G. D. (Eds), 1992. Inversion Tectonics of the Cape Fold Belt, Karoo and Cretaceous basins of Southern Africa. Balkema Rotterdam.
[24]
Ramsay, J. G., 1967. Folding and fracturing of rocks. McGraw-Hill, 568 pp.
[25]
De Villiers, J., Jansen, H. and Mulder, M. P., 1964. The Geology of the area between Worcester and Hermanus. Explanation of sheets 3319C, 3419A, 3318D and 3418B. Geological Survey, Department of Mineral and Energy Affairs, 69 pp.
[26]
Theron, J. N., Wickens, H. de V. and Gresse, P. G., 1991. Die Geologie van die gebied Ladismith, Toeligting van Blad 3320, Geologiese Opname, Dept. van Mineraal en Energiesake.
[27]
Poblet, J. and Lisle, R. J., 2011 (eds). Kinematic Evolution and Structural Styles of Fold-and-Thrust Belts. Geological Society, London, Special Publications, 349, 1–24.
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