Abstract
The Cape Fold Belt (CFB) is a 1300 km long fold-and-thrust mountain belt along the western and southern coastlines of South Africa. A limited understanding of the sedimentary provenance history and poor constraints on the timing of deformation has restricted the ability to provide a coherent tectonic model for the evolution of the CFB. Provenance studies on the Cape Supergroup, which dominates CFB outcrop, are largely limited to U-Pb dating of detrital zircons, which indicate the Namaqua-Natal Metamorphic Complex and Pan-African orogenic belts as likely sources for much of the detritus. Early geochronological studies constraining the timing of deformation in the CFB utilized 40Ar/39Ar step-heating analysis of bulk mineral separates. In these studies, dominant age domains were interpreted as multiple episodes of deformation. More recent 40Ar/39Ar results, from single muscovite grains and aggregate samples, were interpreted in terms of a bimodal tectonic evolution (ca. 270 Ma and ca. 251 Ma) for the CFB. In the present study, preliminary high precision 40Ar/39Ar step-heating analyses were carried out on >100 single muscovite grains from the Cape Supergroup of the Eastern Cape area. These results identify a large detrital muscovite population >440 Ma, confirming sedimentary contributions from Pan-African aged rocks of the Saldanian Orogen and associated Cape Granites, and possibly the East African-Antarctic Orogen. Similar muscovite ages at ca. 253 (Ma) are interpreted as constraining the final stage(s) of CFB orogenesis. Intermediate ages between 255 and 440 Ma are attributed to mixed age populations of detrital and metamorphic micas and/or partial resetting/recrystallization of these components by the low-grade CFB metamorphism. The significant detrital population and presence of partially overprinted micas highlights the risks of using bulk mineral separates, as per previous studies. Collectively, the current geochronological data do not support discrete deformation events, but also do not rule out the possibility of earlier or long-lived deformation events. Consequently, available models for the timing of CFB deformation should be treated with caution.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
References
Andersen, T., Kristoffersen, M. and Elburg, M., 2016. How far can we trust provenance and crustal evolution information from detrital zircons? A South African case study, Gondwana Research (2016), doi:10.1016/j.gr.2016.03.003
Armstrong, R.A., de Wit, M.J., Reid, D., York, D. and Zartman, R., 1998. Cape Town: Table Mountain reveals rapid Pan-African uplift of its basement rocks. Journal of African Earth Science, 27, 10–11.
Bangert, B., Stollhofen, H., Lorenz, V. and Armstrong, R., 1999. The geochronology and significance of ash-fall tuffs in the glaciogenic Carboniferous-Permian Dwyka Group of Namibia and South Africa. Journal of African Earth Sciences, 29, 33–49.
Barnett, W., Armstrong, R. and de Wit, M.J., 1997. Stratigraphy of the Upper Neoproterozoic Kango and lower Palaeozoic Table Mountain Groups of the Cape Fold Belt revisited. South African Journal of Geology, 100, 237–250.
Board, W.S., Frimmel, H.E. and Armstrong, R.A., 2005. Pan-African tectonism in the western Maud Belt: P–T–t path for high-grade gneisses in the H.U. Sverdrupfjella, East Antarctica. Journal of Petrology, 46, 671–699.
Booth, P.W.K., 1996. The relationship between folding and thrusting in the Floriskraal Formation (upper Witteberg Group), Steytlerville, Eastern Cape. South African Journal of Geology 99, 235–243.
Booth, P.W.K., 1998. The effect of thrusting on fold style and orientation, Weltevrede Formation (Cape Supergroup), Steytlerville, Eastern Cape. South African Journal of Geology 101, 27–37.
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, 235–248.
Booth, P.W.K. and Goedhart, M.L., 2014. Thrust faulting in the northernmost foreland zone of the Cape Fold Belt, Fort Beaufort, Eastern Cape, South Africa. South African Journal of Geology, 117, 301–315.
Booth, P.W.K. and Shone, R.W., 1999. Complex thrusting at Uniondale, eastern sector of the Cape Fold Belt, Republic of South Africa: structural evidence for the need to revise the lithostratigraphy. Journal of African Earth Sciences, 29, 125–133.
Booth, P.W.K. and Shone, R.W., 2002. A review of thrust faulting in the Eastern Cape Fold Belt, South Africa, and the implication for current lithostratigraphic interpretation of the Cape Supergroup. Journal of African Earth Sciences, 34, 179–190.
Booth, P.W.K., Brunsdon, G. and Shone, R.W., 2004. A Duplex Model for the Eastern Cape Fold Belt? Evidence from the Palaeozoic Witteberg and Bokkeveld Groups (Cape Supergroup), Near Steytlerville, South Africa. Gondwana Research, 7, 211–222.
Broquet, C.A.M., 1992. The sedimentary record of the Cape Supergroup: a review. In: de Wit, M.J., Ransome, I.G.D. (Editors), In: M.J. de Wit and I.G.D. Ransome (Editors). Inversion tectonics of the Cape Fold Belt, Karoo and Cretaceous Basins of Southern Africa. Balkema, Rotterdam, Netherlands, 159–183.
Chemale, F., Scheepers, R., Gresse, P.G. and Van Schmus, W.R., 2011. Geochronology and sources of late Neoproterozoic to Cambrian granites of the Saldania Belt. International Journal of Earth Sciences, 100, 431–444.
Curtis, M.L. and Hyam, D.M., 1998. Late Palaeozoic to Mesozoic structural evolution of the Falkland Islands: a displaced segment of the Cape Fold Belt. Journal of the Geological Society, 155, 115–129.
da Silva, L.C., Gresse, P.G., Scheepers, R., McNaughton, N.J., Hartmann, L.A. and Fletcher, I.R., 2000. U-Pb SHRIMP and Sm-Nd age constraints on the timing and sources of the Pan-African Cape Granite Suite, South Africa. Journal of African Earth Sciences, 30, 795–815.
de Wit, M.J. and Ransome, I.G.D., 1992. Regional inversion tectonics along the southern margin of Gondwana. In: M.J. de Wit and I.G.D. Ransome (Editors). Inversion tectonics of the Cape Fold Belt, Karoo and Cretaceous Basins of Southern Africa. Balkema, Rotterdam, Netherlands, 15–21.
Egle, S., de Wit, M.J. and Hoernes, S., 1998. Gondwana fluids and subsurface palaeohydrology of the Cape Fold belt and the Karoo Basin, South Africa. Journal of African Earth Sciences, 27, 63–64.
Fergusson, C.L. and Phillips, D., 2001. 40 and K-Ar age constraints on the timing of regional deformation, south coast New South Wales, Lachlan Fold Belt: problems and implications. Australian Journal of Earth Sciences, 48, 395–408.
Fourie, P. H., Zimmermann, U., Beukes, N. J., Naidoo, T., Kobayashi, K., Kosler, J., Nakamura, E., Tait, J. and Theron, J.N., 2011. Provenance and reconnaissance study of detrital zircons of the Palaeozoic Cape Supergroup in South Africa: Revealing the interaction of the Kalahari and Río de la Plata Cratons. International Journal of Earth Sciences, 100, 527–541.
Frimmel, H.E., Fölling P.G. and Diamond, R., 2001. Metamorphism of the Permo-Triassic Cape Fold Belt and its basement, South Africa. Mineral Petrology, 73, 325–346.
Gentle, R.I., Hooker, P.J., Fitch, F.J. and Miller, J.A., 1978. Evidence for Cape Fold Belt overprinting of the Groot Haelkraal granite during the Upper Permian. Transactions of the Geological Society of South Africa, 81, 105–107.
Gohl, K., Uenzelmann-Neben, G. and Grobys, N., 2011. Growth and dispersal of a southeast African Large Igneous Province. South African Journal of Geology, 114, 379–386.
Gresse, P.G., Theron, J.N., Fitch, F.J. and Miller, J.A., 1992. Tectonic inversion and radiometric resetting of the basement in the Cape Fold Belt. In: M.J. de Wit and I.G.D. Ransome (Editors). Inversion tectonics of the Cape Fold Belt, Karoo and Cretaceous Basins of Southern Africa. Balkema, Rotterdam, Netherlands, 217–228.
Gresse, P.G., Von Veh, M.W. and Frimmel, H.E., 2006. Namibian, (Neoproterozoic) to early Cambrian successions. In: M.R. Johnson, C.R. Anhaeusser and R.J. Thomas, (Editors), The Geology of South Africa, Geological Society of South Africa, Council For Geoscience, 395–420.
Hälbich, I.W. and Cornell, D.H., 1983. Metamorphic history of the Cape Fold Belt. In: A.P.G. Söhnge and I.W. Hälbich (Editors) Geodynamics of the Cape Fold Belt, Special Publications of the Geological Society of South Africa, Johannesburg. 12, 131–148.
Hälbich, I. W., 1983. Disharmonic folding, detachment and thrusting in the Cape Fold Belt. In: A.P.G. Söhnge and I.W. Hälbich (Editors), Geodynamics of the Cape Fold Belt. Special Publications of the Geological Society of South Africa, Johannesburg, 12, 115–124.
Hälbich, I.W., Fitch, F.J. and Miller, J.A., 1983. Dating the Cape Orogeny. In: A.P.G. Söhnge and I.W. Hälbich (Editors), Geodynamics of the Cape Fold Belt. Special Publications of the Geological Society of South Africa, Johannesburg, 12, 75–100.
Hansma, J., Tohver, E., Schrank, C., Jourdaan, F. and Adams, D., 2015. The timing of the Cape Orogeny: New 40Ar/39Ar age constraints on deformation and cooling of the Cape Fold Belt, South Africa. Gondwana Research, doi:10.1016/j.gr.2015.02.005.
Harrison T. M., Célérier J., Aikman A. B., Hermann J. and Heizler M. T., 2009. Diffusion of 40Ar in muscovite. Geochimica et Cosmochimica Acta 73, 1039– 1051.
Jacobs, J., Ahrendt, H., Kreutzer, H., Weber, K., 1995. K–Ar, 40Ar–39Ar and apatite fission track evidence for Neoproterozoic and Mesozoic basement rejuvenation events in the Heimefrontfjella and Mannefallknausane (East Antarctica). Precambrian Research, 75, 251–263.
Jacobs, J., Fanning, C.M., Henjes-Kunst, F., Olesch, M. and Paech, H.-J., 1998. Continuation of the Mozambique belt into East Antarctica: Grenville-age metamorphism and polyphase Pan-African high-grade events in central Dronning Maud Land. Journal of Geology, 106, 385–406.
Jacobs, J., Fanning, C.M. and Bauer, W., 2003. Timing of Grenville-age vs. Pan-African medium- to high grade metamorphism in western Dronning Maud Land (East Antarctica) and significance for correlations in Rodinia and Gondwana. Precambrian Research, 125, 1–20.
Jacobs, J. and Thomas, R.J., 2004. Himalayan-type indenter-escape tectonics model for the southern part of the late Neoproterozoic–early Paleozoic East African-Antarctic orogen. Geology, 32, 721–724.
Johnston, S., 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, 51–63.
Jourdan, F., Féraud, G., Bertrand, H., Watkeys, M.K., Renne, P.R., 2008. The 40Ar/39Ar ages of the sill complex of the Karoo large igneous province: implications for the Pliensbachian–Toarcian climate change. Geochem. Geophys. Geosyst., 9, Q06009. doi:10.1029/2008GC001994.
Lee, J. K. W., Williams, I. S. and Ellis, D. J., 1997. Pb, U and Th diffusion in natural zircon. Nature 390, 159–162.
Lee, J.-Y., Marti, K., Severinghaus, J.P., Kawamura, K., Yoo, H.-S., Lee, J.B. and Kim, J.S., 2006. A redetermination of the isotopic abundances of atmospheric Ar. Geochimica et Cosmochimica Acta, 70, 4507–4512.
Lindeque, A., de Wit, M.J., Ryberg, T., Weber, M. and Chevallier, L., 2011. Deep crustal profile across the southern Karoo Basin and Beattie Magnetic Anomaly, South Africa: An integrated interpretation with tectonic implications. South African Journal of Geology, 114, 265–292.
McDougall I. and Harrison T. M., 1999 Geochronology and Thermochronology by the 40Ar/30Ar Method. Oxford University Press, New York, 1999.
Miller, W., Armstrong, R.,and de Wit, M., 2016. Geology and U/Pb geochronology of the Gamtoos Complex and lower paleozoic Table Mountain Group, Cape Fold Belt, Eastern Cape, South Africa. South African Journal of Geology, 119, 147–170.
Pángaro, F. and Ramos, V.A., 2012. Paleozoic crustal blocks of onshore and offshore central Argentina: New pieces of the southwestern Gondwana collage and their role in the accretion of Patagonia and the evolution of Mesozoic south Atlantic sedimentary basins. Marine and Petroleum Geology, 37, 162–183.
Paton, D.A., Macdonald, D.I.M. and Underhill, J.R., 2006. Applicability of thin or thick skinned structural models in a region of multiple inversion episodes; southern South Africa. Journal of Structural Geology, 28, 1933–1947.
Phillips, D. and Matchan, L., 2013. Ultra-high precision 40Ar/39Ar ages for Fish Canyon Tuff and Alder Creek Rhyolite sanidine: New dating standards required? Geochimica et Cosmochimica Acta, 121, 229–239.
Rapela, C.W., Pankhurst, R.J., Fanning, C.M. and Grecco, L.E., 2003. Basement evolution of the Sierra de la Ventana Fold Belt: new evidence for Cambrian continental rifting along the southern margin of Gondwana. Journal of the Geological Society, London, 160, 613–628.
Renne P.R., Swisher C.C., Deino A.L., Karner D.B., Owens T.L. and De Paolo D.J., 1998. Intercalibration of standards, absolute ages and uncertainties in 40Ar/39Ar dating. Chem. Geol. 145, 117–152.
Renne, P.R., Deino, A.L., Hames, W.E., Heizler, M.T., Hemming, S.R., Hodges, K.V., Kopers, A.A.P., Mark, D.F., Morgan, L.E., Phillips, D., Singer, B.S., Turrin, B.D., Villa, I.M., Villeneuve, M. and Wijbrans, J.R., 2009. Data reporting norms for 40Ar/39Ar geochronology. Quaternary Geochronology, 4, 346–352.
SACS (South African Committee for Stratigraphy), (1980): Stratigraphy of South Africa. Part I. (Compiled by L.E. Kent). Lithostratigraphy of the Republic of South
Steiger, R.H. and Jäger, E., 1977. Subcommission on geochronology: convention on the use of decay constants in geo- and cosmochronology. Earth and Planetary Science Letters, 36, 359–362.
Vorster, C. 2013. Laser ablation ICP-MS age determination of detrital zircon populations in the Phanerozoic Cape and Lower Karoo Supergroups (South Africa) and correlatives in Argentina. Unpublished PhD. Thesis, University of Johannesburg, South Africa, 648p.
Acknowledgments
The authors thank Maarten de Wit, Peter Booth, Bastien Linol, and Warren Miller for their guidance and assistance in the field. Dr. Erin Matchan and Stan Szczepanski are thanked for technical assistance in the 40Ar/39Ar laboratory. Insightful and constructive comments were greatly appreciated from reviewers Jan Kramers and Maarten de Wit.
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2016 Springer International Publishing Switzerland
About this chapter
Cite this chapter
Blewett, S.C.J., Phillips, D. (2016). An Overview of Cape Fold Belt Geochronology: Implications for Sediment Provenance and the Timing of Orogenesis. In: Linol, B., de Wit, M. (eds) Origin and Evolution of the Cape Mountains and Karoo Basin. Regional Geology Reviews. Springer, Cham. https://doi.org/10.1007/978-3-319-40859-0_5
Download citation
DOI: https://doi.org/10.1007/978-3-319-40859-0_5
Published:
Publisher Name: Springer, Cham
Print ISBN: 978-3-319-40858-3
Online ISBN: 978-3-319-40859-0
eBook Packages: Earth and Environmental ScienceEarth and Environmental Science (R0)