Abstract
The continental margin of SW Africa is typical of a volcanic rifted margin associated with a hotspot trail characterized by a large volcanic ridge, the Walvis Ridge, defining the hotspot migration, and extensive extrusive volcanism that produced seaward-dipping reflectors (SDR). Previously unpublished seismic data show two significant anomalies of the SW African Margin when compared to other typical volcanic rifted margins: (1) Hyaloclastitic outer highs are rare, and (2) the SDR in the North dip towards the Walvis Ridge. We explain these anomalies by a major transform segment close to the centre of volcanism combined with pulsed volcanism. The Walvis Ridge represents an east-west striking extrusive centre which produced a SDR sequence. Following break-up the northern boundary of the Walvis Ridge became a left lateral transform fault. Our data support the idea that a transform fault system interacting with a ridge jump were responsible for the accretion of the São Paulo Plateau to the American plate.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Abreu V (1998) Geologic evolution of conjugate volcanic passive margins: Pelotas Basin (Brazil) and offshore Namibia (Africa): implications for global sea level changes, Ph.D. thesis, 355 pp, Rice University, Houston, Tex
Bauer K, Schulze A (1996) Seismic investigations of the passive continental margin of Namibia from wide-angle on-shore off-shore data. EOS Trans AGU 77:F669
Bauer K, Neben S, Schreckenberger B et al (2000) Deep structure of the Namibia continental margin as derived from integrated geophysical studies. J Geophys Res 105(B11):5829–25853. doi:10.1029/2000JB900227
Berndt C, Planke S, Alvestad E et al (2001a) Seismic volcanostratigraphy of the Norwegian Margin: constraints on tectonomagmatic break-up processes. J Geol Soc 158:413–426
Berndt C, Mjelde R, Planke S et al (2001b) Controls on the tectono-magmatic evolution of a volcanic transform margin: the Vøring Transform Margin, NE Atlantic. Mar Geophys Res 22:133–152. doi:10.1023/A:1012089532282
Dragoi-Stavar D, Hall D (2009) Gravity modelling of the ocean-continent transition along the South Atlantic margins. J Geophys Res 114:B09401. doi:10.1029/2008JB006014
Elliott GM, Parson LM (2008) Influence of margin segmentation upon the break-up of the Hatton Bank rifted margin, NE Atlantic. Tectonophys 457:161–176. doi:10.1016/j.tecto.2008.06.008
Franke D, Neben S, Ladage S et al (2007) Margin segmentation and volcano-tectonic architecture along the volcanic margin off Argentina/Uruguay, South Atlantic. Mar Geol 244:1–13. doi:10.1016/j.margeo.2007.06.009
Gladczenko TP, Hinz K, Eldholm O et al (1997) South Atlantic volcanic margins. J Geol Soc 154:465–470. doi:10.1144/gsjgs.154.3.0465
Gladczenko TP, Skogseid J, Eldholm O (1998) Namibia volcanic margin. Mar Geophys Res 20:313–341. doi:10.1023/A:1004746101320
Hinz K, Neben S, Schreckenberger B et al (1999) The Argentine continental margin north of 48°S: sedimentary successions, volcanic activity during breakup. Mar Pet Geol 16:1–25. doi:10.1016/S0264-8172(98)00060-9
Hopper JR, Dahl-Jensen T, Holbrook WS et al (2003) Structure of the SE Greenland margin from seismic reflection and refraction data: implications for nascent spreading center subsidence and asymmetric crustal accretion during North Atlantic opening. J Geophys Res 108(B5). doi:10.1029/2002JB001996
Light MPR, Maslanyj MP, Greenwood RJ et al (1993) Seismic sequence stratigraphy and tectonics offshore Namibia. In: Williams GD, Dobb A (eds) Tectonics and seismic sequence stratigraphy. Spec Pub Geol Soc London, vol 71, pp 163-191
Macdonald D, Gomez-Perez I, Franzese J et al (2003) Mesozoic break-up of SW Gondwana: implications for regional hydrocarbon potential of the southern South Atlantic. Mar Pet Geol 20:287–308. doi:10.1016/S0264-8172(03)00045-X
Nürnberg D, Müller RD (1991) The tectonic evolution of the South-Atlantic from late jurassic to present. Tectonophys 191:27–53. doi:10.1016/0040-1951(91)90231-G
O’Connor JM, Duncan RA (1990) Evolution of the Walvis Ridge-Rio Grande Rise hotspot system: implications for African and South American plate motions over plumes. J Geophys Res 95:17475–17502. doi:10.1029/JB095iB11p17475
Pawlowski R (2008) The use of gravity anomaly data for offshore continental margin demarkation. The Leading Edge, June, 722–727. doi:10.1190/1.2944156
Planke S, Symonds PA, Alvestad E et al (2000) Seismic volcanostratigraphy of large-volume basaltic extrusive complexes on rifted margins. J Geophys Res 105(B8):19335–19351. doi:10.1029/1999JB900005
Rabinowitz PD, LaBrecque J (1979) The Mesozoic South Atlantic Ocean and evolution of its continental margins. J Geophys Res 84:5973–6002. doi:10.1029/JB084iB11p05973
Roberts DG (1984) Evolution of volcanic rifted margins: Synthesis of Leg 81 results on the west margin of Rockall. In: Roberts DG, Schneider ED (eds) Init Rep deep sea drilling project Leg 81 US government printing office, Washington, pp 883–923
Sibuet J-C, Hay WH, Prunier A et al (1984) The eastern Walvis Ridge and adjacent basins (South Atlantic): morphology, stratigraphy and structural evolution in light of the results of Legs 40 and 75. In: Hay WH, Sibuet J-C (eds) Init Rep deep sea drilling project Leg 75 US government printing office, Washington, pp 483–508
Symonds PA, Planke S, Frey O et al (1998) Volcanic evolution of the Western Australian continental margin and its implications for basin development. In: Purcell PG, Purcell RR (eds) The sedimentary basins of Western Australia 2. Proceedings of the petroleum exploration society of Australia symposium, Perth, WA, pp 33–53
Acknowledgments
We thank Western Geco for making the seismic data available to this study. The quality of this work was improved significantly due to comments raised by two anonymous reviewers and by editor Peter Clift.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Elliott, G.M., Berndt, C. & Parson, L.M. The SW African volcanic rifted margin and the initiation of the Walvis Ridge, South Atlantic. Mar Geophys Res 30, 207–214 (2009). https://doi.org/10.1007/s11001-009-9077-x
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11001-009-9077-x