1887
Volume 19, Issue 3
  • E-ISSN: 1365-2117

Abstract

ABSTRACT

The East African Rift system has long been considered best modern example of the initial stages of continental rifting. The Malawi Rift is characteristic of the western branch of the East African Rift system, composed of half‐grabens of opposing asymmetry along its length. There are striking similarities between basins within the Malawi Rift, and others along the western branch. Each exhibits similar bathymetry, border‐fault length, rift zone width and fault segment length. The North Basin of the Malawi Rift differs from others in the rift only in its orientation: trending NW–SE as opposed to N–S. Although there is general agreement as to the geometry of the Malawi Rift; debate as to the amount of strike–slip vs. dip–slip deformation and the influence of underlying Pan‐African foliation remains. This study presents new data from a closely spaced shallow [2 s two‐way travel time (TWT)] seismic reflection data set integrated with basin‐scale deeper (6 s TWT) seismic reflection data that document the structural evolution of the border and intra‐basin faults. These data reveal that the different trend of the North Basin, most likely to have been influenced by the underlying Pan‐African foliation, has played an extremely important role in the structural style of basin evolution. The border‐fault and intra‐basin structures nucleated during extension that was initially orthogonal (ENE). During this time (>8.6 to ∼0.5–0.4 Ma) intra‐basin faults synthetic to the west‐dipping border‐fault nucleated, whereas strain was localised on the segmented border‐fault early on. A later rotation of extension orientation (to NW) led to these established faults orienting oblique to rifting. This generated an overall dextral strike–slip setting that led to the development of transfer faults adjacent to the border‐fault, and the generation of flower structures and folds over the greater displacement intra‐basin faults.

Loading

Article metrics loading...

/content/journals/10.1111/j.1365-2117.2007.00332.x
2007-08-28
2024-04-20
Loading full text...

Full text loading...

References

  1. Bally, W. (1982) Musings over sedimentary basin evolution. Philos. Trans. Roy. Soc. Lond. Ser. A, 305, 325–328.
    [Google Scholar]
  2. Bosworth, W. (1985) Geometry of propagating rifts. Nature, 316, 625–627.
    [Google Scholar]
  3. Bosworth, W. & Strecker, M.R. (1997) Stress field changes in the Afro‐Arabian rift system during the Miocene to recent period. Tectonophysics, 278, 47–62.
    [Google Scholar]
  4. Cartwright, J.A., Trudgill, B.D. & Mansfield, C.S. (1995) Fault growth by segment linkage: an explanation for scatter in maximum displacement and trace length data from the Canyonlands Grabens of SE Utah. J. Struct. Geol., 17, 1319–1326.
    [Google Scholar]
  5. Chorowitz, J. & Mukonki, M.N.B (1980) Lineaments anciens, zones transformantes recentes et geotectonique. Mues. Roy. Afr. Centr. Dept. Geol. Min ‘Rap. Annu. Inst. Interuniv. Sci. Nucl., 1979, 143–167.
    [Google Scholar]
  6. Clifton, A.E., Schlische, R.W., Withjack, M.O. & Ackermann, R.V. (2000) Influence of rift obliquity on fault‐population systematics: results of experimental clay models. J. Struct. Geol., 22, 1491–1509.
    [Google Scholar]
  7. Contreras, J., Anders, M.H. & Scholz, C.H. (2000) Growth of a normal fault system: observations from the Lake Malawi basin of the east African rift. J. Struct. Geol., 22, 159–168.
    [Google Scholar]
  8. Cowie, P.A., Gupta, S. & Dawers, N.H. (2000) Implications of fault array evolution for syn‐rift depocentre development: insights from a numerical fault-growth model. Basin Res., 12, 241–261.
    [Google Scholar]
  9. Dawers, N.H., Anders, M.H. & Scholz, C.H. (1993) Growth of normal faults: displacement-length scaling. Geology, 21, 1107–1110.
    [Google Scholar]
  10. Dawers, N.H. & Underhill, J.R. (2000) The role of fault interaction and linkage in controlling syn‐rift stratigraphic sequences: late Jurassic, Statfjord East area, northern North Sea. Bull. Am. Assoc. Petrol. Geol., 84 (1), 45–64.
    [Google Scholar]
  11. Delvaux, D., Levi, K., Kajara, R. & Sarota, J. (1992) Cenozoic paleostress and kinematic evolution of the Rukwa‐north Malawi Rift valley (EARs). Bull. Cent. Rech. Explor. – Prod Elf Acquitaine, 16, 383–406.
    [Google Scholar]
  12. Ebinger, C.J., Crow, M.J., Rosendahl, B.R., Livingstone, D.A. & Le Fournier, J. (1984) Structural evolution of Lake Malawi, Africa. Nature, 308, 627–629.
    [Google Scholar]
  13. Ebinger, C.J., Deino, A.L., Drake, R.E. & Tesha, A.L. (1989) Chronology of volcanism and rift basin propagation: Rungwe volcanic province, East Africa. J. Geophys. Res., 94, 15785–15803.
    [Google Scholar]
  14. Ebinger, C.J., Deino, A.L., Tesha, A.L., Becker, T. & Ring, U. (1993) Tectonic controls on rift basin morphology: evolution of the Northern Malawi (Nyasa) rift. J. Geophys. Res., 98, 17821–17836.
    [Google Scholar]
  15. Ebinger, C.J., Rosendahl, B.R. & Reynolds, D.J. (1987) Tectonic model of the Malawi Rift, Africa. Tectonophysics, 141, 215–235.
    [Google Scholar]
  16. Flannery, J.W. & Rosendahl, B.R. (1990) The seismic stratigraphy of Lake Malawi: implications for interpreting geological processes in lacustrine rifts. J. Afr. Earth Sci., 10, 519–548.
    [Google Scholar]
  17. Gibbs, A.D. (1984) Structural evolution of extensional basin margins. J. Geol. Soc. London, 141, 609–620.
    [Google Scholar]
  18. Gupta, S., Cowie, P.A., Dawers, N.H. & Underhill, J.R. (1998) A mechanism to explain rift‐basin subsidence and stratigraphic patterns through fault array evolution. Geology, 26, 595–598.
    [Google Scholar]
  19. Hubbard, R.J., Pape, J. & Roberts, D.G. (1985a) Depositional sequence mapping as a technique to establish tectonic and stratigraphic framework and evaluate hydrocarbon potential on a passive continental margin. In: Seismic Stratigraphy II (Ed. by O.R.Beerg & D.G.Wooverton ), AAPG Memoir , 29, 79–92.
    [Google Scholar]
  20. Hubbard, R.J., Pape, J. & Roberts, D.G. (1985b) Depositional sequence mapping as a technique to establish tectonic and stratigraphic framework and evaluate hydrocarbon potential on a passive continental margin. In: Seismic Stratigraphy II (Ed. by O.R.Beerg & D.G.Wooverton ), AAPG Memoir , 29, 93–116.
    [Google Scholar]
  21. Lezzar, K.E., Tiercelin, J., Le Turdu, C., Cohen, A.S., Reynolds, D.J., Le Gall, B. & Scholz, C.A (2002) Control of normal fault interaction on the distribution of major Neogene sedimentary depocentres, Lake Tanganyika, East African Rift. AAPG Bull., 86, 1027–1059.
    [Google Scholar]
  22. Lister, G.S., Etheridge, M.A. & Symonds, P.A. (1986) Detachment faulting and the evolution of passive continental margins. Geology, 14, 246–250.
    [Google Scholar]
  23. McClay, K.R., Dooley, T., Whitehouse, P. & Mills, M. (2002) 4‐D evolution of rift systems: insights from scale physical models. AAPG Bull., 86, 935–959.
    [Google Scholar]
  24. McLeod, A.E., Dawers, N.H. & Underhill, J.R. (2000) The propagation and linkage of normal faults: insights from the Strathspey-Brent-Statfjord fault array, northern North Sea. Basin Res., 12, 263–284.
    [Google Scholar]
  25. Mitchum, R.M.Jr, Vail, P.R. & Sangree, J.B. (1977) Seismic stratigraphy and global changes of sea‐level part 6: seismic stratigraphic interpretation procedure. In: Seismic Stratigraphy – Applications to Hydrocarbon Exploration (Ed. by C.E.Payton ), APPG Memoir , 26, 117–134.
    [Google Scholar]
  26. Paton, D.A. (2006) Influence of crustal heterogeneity on normal fault dimensions and evolution: southern South Africa extensional system. J. Struct. Geol., 28, 868–886.
    [Google Scholar]
  27. Prosser, S. (1993) Rift‐related linked depositional systems and their seismic expression. In: Tectonics and Seismic Sequence Stratigraphy (Ed. by G.D.Williams & A.Dobb ), Spec. Publ. Geol. Soc. Lond. , 71, 35–66.
    [Google Scholar]
  28. Reinecker, J., Heidbach, O., Tingay, M., Sperner, B. & Müller, B. (2005) The release 2005 of the World Stress Map (available online at http://www.world‐stress‐map.org).
  29. Reynolds, D.J. (1984) Morphology and structural repetition in rifts. Masters Thesis, Duke University, Durham, NC, USA.
  30. Reynolds, D.J. & Rosendahl, B.R. (1984) Tectonic expressions of continental rifting. EOS. Trans AGU, 65, 1116.
    [Google Scholar]
  31. Ring, U. (1994) The influence of pre‐existing structure on the evolution of the Cenozoic Malawi Rift (East African Rift System). Tectonics, 13, 313–326.
    [Google Scholar]
  32. Ring, U., Betzler, C. & Delvaux, D. (1992) Normal vs. strike–slip faulting during rift development in East Africa: the Malawi Rift. Geology, 20, 1015–1018.
    [Google Scholar]
  33. Rosendahl, B.R. (1987) Architecture of continental rifts with special reference to East Africa. Ann. Rev. Earth Planet: Sci, 15, 445–503.
    [Google Scholar]
  34. Schlische, R.W. & Anders, M.H. (1996) Stratigraphic effects and tectonic implications of the growth of normal faults and extensional basins. GSA Spec. Pap., 303, 183–203.
    [Google Scholar]
  35. Scholz, C.A. (1989) Project PROBE geophysical atlas series, Duke University, Durham, NC.
  36. Scholz, C.A. (1995) Seismic stratigraphy of an accommodation‐zone margin rift‐lake delta, Lake Malawi, Africa. In: Hydrocarbon Habitat in Rift Basins (Ed. by J.J.Lambiase ), Spec. Publ. Geol. Soc. , 80, 183–195.
    [Google Scholar]
  37. Strecker, M.R., Blisniuk, P.M. & Eisbacher, G.H. (1990) Rotation of extension direction in the central Kenya Rift. Geology, 18, 299–302.
    [Google Scholar]
  38. Trudgill, B. & Cartwright, J. (1994) Relay‐ramp forms and normal‐fault linkages, Canyonlands National Parl, Utah. GSA Bull., 106, 1143–1157.
    [Google Scholar]
  39. Versfelt, J.W. & Rosendahl, B.R. (1989) Relationships between pre‐rift structures and rift architecture in Lakes Tanganyika and Malawi, East Africa. Nature, 337, 354–357.
    [Google Scholar]
  40. Wheeler, W.H. & Karson, J.A. (1989) Structure and kinematics of the Livingstone mountain border‐fault zone, Nyasa (Malawi) rift, south‐western Tanzania. J. Afr. Earth Sci., 8, 393–414.
    [Google Scholar]
  41. Wheeler, W.H. & Rosendahl, B.R. (1994) Geometry of the Livingstone Mountains Border‐fault, Nyasa (Malawi) Rift, East Africa. Tectonics, 13, 303–312.
    [Google Scholar]
http://instance.metastore.ingenta.com/content/journals/10.1111/j.1365-2117.2007.00332.x
Loading
/content/journals/10.1111/j.1365-2117.2007.00332.x
Loading

Data & Media loading...

  • Article Type: Research Article

Most Cited This Month Most Cited RSS feed

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error