Rv. Dingle et al., MODERN AND PALEOCEANOGRAPHIC ENVIRONMENTS UNDER BENGUELA UPWELLING CELLS OFF SOUTHERN NAMIBIA, Palaeogeography, palaeoclimatology, palaeoecology, 123(1-4), 1996, pp. 85-105
Averaged benthic physical and chemical, and key microfaunal (Ostracoda
) parameters of the bottom waters and substrate allow a ranking of the
intensity of upwelling in the modern cells off southwestern Africa (B
1-B6): B1 Namib cell (temperature, salinity, dissolved oxygen, total o
rganic matter: 10.3 degrees C, 34.94 parts per thousand, 1.2 ml/l, 6.2
%): Palmoconcha walvisbaiensis, Cytherella namibensis, Garciaella knys
naensis robusta and Neocaudites lordi. B2 Walvis cell (11.0 degrees C,
35.00 parts per thousand, 1.0 ml/l, 9.2%): Palmoconcha walvisbaiensis
, Cytherella namibensis, Garciaella knysnaensis robusta, Buntonia roge
rsi, Neocaudites lordi and Ruggieria cytheropteroides (leeward side on
ly). B3 Luderitz cell (9.1 degrees C, 34.77 parts per thousand, 1.8 ml
/l, 6.3%): Palmoconcha walvisbaiensis, Cytherella namibensis, Incongru
ellina venusta, Kuiperiana angulata, and Ruggieria cytheropteroides (l
eeward side only). B4 Namaqua cell (10.0 degrees C, 34.82 parts per th
ousand, 2.4 ml/l, 3.1%): Pseudokeijella lepralioides and Ruggieria cyt
heropteroides. B5 Columbine cell (8.3 degrees C, 34.70 parts per thous
and, 3.1 ml/l, 3.9%): Ruggieria cytheropteroides, Pseudokeijella lepra
lioides, Poseidonamicus panopsus and Ambostracon (A.) flabellicostata.
B6 Peninsula cell (8.9 degrees C, 34.63 parts per thousand, 3.6 ml/l,
1.9%): Pseudokeijella lepralioides, Ambostracon (A.) keeleri, Cythere
lla dromedaria, Neocytherideis boomeri, Xestoleberis africana, Neocaud
ites osseus, Coquimba birchi and Urocythereis arcana. Pleistocene pala
eo-upwelling characteristics of the shelf north-west of Luderitz are i
nvestigated by analysing the ostracod faunas, sediment textures and mi
neralogy of three large-volume gravity cores. Q-mode factor analyses u
sing previously published transfer functions allow predictions for ben
thic environmental parameters. During the Late Pleistocene the area ex
perienced less-intense upwelling and lower primary productivity than a
t present, in an environment equated with a modified Peninsula cell (B
6): B7 cell (9.6 degrees C, 34.73 parts per thousand, 3.2 ml/l, 3.9%),
Neocaunites lordi, Ambostracon (A.) keeleri, Bairdoppilata simplex, P
aracypris lacrimata, Parakrithella simpsoni, Xestoleberis hartmanni, R
uggieria cytheropteroides and Pseudokeijella lepralioides. In Middle a
nd Early Pleistocene/Late Pliocene times, the core sites lay closer in
shore, adjacent to evaporite (halite) and authigenic (phosphorite)-ric
h lagoons, with a high-intensity upwelling Walvis-like cell (B1) to th
e north-west, and a low-intensity upwelling cell (B7) to the south.