Diamond-Bearing Gravels Along the Lower Kwango River DRC - Geology and Resource Potential of the Congo Basin - page 337

Fig. 16.7 Longitudinal profile of the Kwango River in the Tembo area ( top ) with a photograph of the lower part of the Francois-Joseph Falls

south where the highly resistive granite/gneiss bedrock
provides better contrast than the sedimentary footwall in the
northern areas. Despite the fact that the conductivity contrast
is lower on these less competent rocks resistivity-lows on the
flats, such as at K52, have been interpreted to be associated
with palaeo-channels. These are water-logged clayey material
adjacent to the river where pitting in areas coincident with

electromagnetic lows has confirmed the presence of this
clayey, sandy and gravel material. Although pitting could
not reach deeper areas concave resistivity lows within the
flats were interpreted as arcuate palaeo-channels, and in
many areas the current artisanal workings follow these
features.