Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum . ve through theAgulhas Passage (Westall 1984); AABW is forced to its right, whilst the NADWcontinues north-eastwards. The sudden change in direction of AABW, where itencounters a rising sea-floor formed by the terrigenous apron from the east-coastslumps and canyon feeders, originally targeted deposition along a narrow zoneand resulted in the formation of the 480 km long Agulhas Drift (Figs 1, 5) (E-WRidge of Westall 1984). Truncated bedding planes along its southern flanksuggest that modern AABW may be eroding the Agul
Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum . ve through theAgulhas Passage (Westall 1984); AABW is forced to its right, whilst the NADWcontinues north-eastwards. The sudden change in direction of AABW, where itencounters a rising sea-floor formed by the terrigenous apron from the east-coastslumps and canyon feeders, originally targeted deposition along a narrow zoneand resulted in the formation of the 480 km long Agulhas Drift (Figs 1, 5) (E-WRidge of Westall 1984). Truncated bedding planes along its southern flanksuggest that modern AABW may be eroding the Agulhas Drift (Dingle &Camden-Smith 1979). A model for steady-state targeted sedimentation under the influence of theNADW is presented in Figure 5. Bottom-water potential temperatures (Kollaet al. 1980, fig. 7) indicate that along the continental slope and rise off south-eastAfrica, NADW flows north-east beneath the south-west flowing AgulhasCurrent. After eastward deflection around the southern face of the Tugela Cone SOUTHERN AFRICAN DEEP-SEA SEDIMENTARY ENVIRONMENTS 15. - / N. , N^.\. ^rVVvK :&£$#& i\in-;; .-->> ^4-,-,;. &-$&& 16 ANNALS OF THE SOUTH AFRICAN MUSEUM (which here is banked behind the buried South Tugela Ridge), further northwardprogress of the NADW is stopped by the southern face of the Naude Ridge(Goodlad 1986). This barrier rises from 2,5 to 1,8 km water depth, and deflectsthe water mass southward down the eastern side of the Natal Valley along thewestern flank of the Mozambique Ridge, at the southern end of which the AABWand NADW masses reunite and flow eastwards and then northwards into theMozambique Basin (Kolla et al. 1980). Two long (at least 300 km) sediment driftsoccur in the eastern Natal Valley adjacent to the Mozambique Ridge, and bothindicate long-term, steady-state, targeted deposition (Dingle & Robson 1985).We postulate that the East Transkei Drift forms from fine suspensate that hascirculated round the Natal Valley (much of it probably
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