MARGINAL upwarps are common features of rifted continental margins1,2, but tectonic models of the evolution of rifted margins have not adequately explained their form, or their persistence along some margins more than 100 Myr after continental rupture. Marginal upwarps not only significantly influence the geomorphological evolution of rifted margins and their adjacent continental interiors, but are also important in determining patterns of offshore sedimentation. Here we show that the contrast in denudation rates between the evolving coastal flanks of rifted margins and their interior hinterlands can promote significant marginal upwarps if the lithosphere responds flexurally to the resulting differential unloading2,3. Using data for the western margin of southern Africa, we demonstrate that upwarps of 600 m with respect to the adjacent continental interior can be generated by this process independently of the mechanics of rifting.
This is a preview of subscription content, access via your institution
Subscribe to this journal
Receive 51 print issues and online access
$199.00 per year
only $3.90 per issue
Rent or buy this article
Get just this article for as long as you need it
Prices may be subject to local taxes which are calculated during checkout
Oilier, C. D. (ed.) Z. Geomorph. Suppl. 54 (1985).
Summerfield, M. A. in Tectonic Geomorphology (eds Morisawa, M. & Hack, J. T.) 27–51 (Allen & Unwin, Boston, 1985).
Thomas, M. F. & Summerfield, M. A. in Int. Geomorph. 1985, Proc. 1st Int. Conf. on Geomorphology (eds Gardiner, V. et al.) 935–956 (Wiley, Chichester, 1987).
Buck, W. R. Earth planet. Sci. Lett. 77, 362–372 (1986).
Buck, W. R., Martinez, F., Steckler, M. S. & Cochran, J. R. Tectonics 7, 213–234 (1988).
McKenzie, D. P. Nature 307, 616–618 (1984).
Braun, J. & Beaumont, C. Geology 17, 760–764 (1989).
Weissel, J. K. & Karner, G. D. J. geophys. Res. 94, 13919–13950 (1989).
Royden, L. & Keen, C. E. Earth planet. Sci. Lett. 51, 343–361 (1980).
White, N. & McKenzie, D. P. Geology 16, 250–253 (1988).
White, R. S. & McKenzie, D. P. J. geophys. Res. 94, 7685–7729 (1989).
Cox, K. G. Nature 342, 873–877 (1989).
Bohannon, R. G., Naeser, C. W., Schmidt, D. L. & Zimmermann, R. A. J. geophys. Res. 94, 1683–1701 (1989).
Rust, D. J. & Summerfield, M. A. Mar. Petrol Geol. (in the press).
Brown, R. W., Rust, D. J., Summerfield, M. A., Gleadow, A. J. W. & De Wit, M. C. J. Nucl. Tracks (in the press).
Moore, M. E., Gleadow, A. J. W. & Lovering, J. F. Earth planet. Sci. Lett. 78, 255–270 (1986).
Oelofsen, B. W. Geophys. Monogr. 41, 131–138 (1987).
Ahnert, F. Am. J. Sci. 268, 243–263 (1970).
Gerrard, I. & Smith, G. C. Am. Ass. Petrol. Geol. Mem. 34, 49–74 (1980).
Stephenson, R. Geophys. J. R. astr. Soc. 77, 385–413 (1984).
Lambeck, K. & Stephenson, R. Aust. J. Earth Sci. 33, 253–270 (1986).
Moretti, I. & Turcotte, D. L. J. Geodyn. 3, 155–168 (1985).
Culling, W. E. H. J. Geol. 73, 230–254 (1965).
Nadai, A. Theory of Flow and Fracture of Solids (McGraw-Hill, New York, 1963).
Karner, G. D. & Watts, A. B. J. geophys. Res. 87, 2923–2948 (1982).
Ebinger, C. J., Bechtel, T. D., Forsyth, D. W. & Bowin, C. O. J. geophys. Res. 94, 2883–2901 (1989).
Speight, J. G. in The Age of Landforms in Eastern Australia: Tech. Memo. 87/2, 61–65 (CSIRO Div. Water and Land Resources, Canberra, 1987).
Summerfield, M. A. Area 13, 3–8 (1981).
Partidge, T. C. & Maud, R. R. S. Afr. J. Geol. 90, 179–208 (1987).
Rights and permissions
About this article
Cite this article
Gilchrist, A., Summerfield, M. Differential denudation and flexural isostasy in formation of rifted-margin upwarps. Nature 346, 739–742 (1990). https://doi.org/10.1038/346739a0
This article is cited by
Denudation history of the Great Escarpment in the southwestern flank of the Angola (Bié) Dome, Africa
International Journal of Earth Sciences (2023)
Rapid mantle-driven uplift along the Angolan margin in the late Quaternary
Nature Geoscience (2016)
By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.