Cenozoic Landscape Evolution in and Around the Congo Basin: Constraints from Sediments and Planation Surfaces - Geology and Resource Potential of the Congo Basin - page 267

450 km 360 km 180 400 km 370 km

BATEKE PLATEAU
(Koukouya)

MBANDAKA 1
well

GILSON 1
well

DEKESE
borehole

SAMBA
borehole

YANGAMBI
(Kisangani area)

CUTTINGS

Sand Sand Sand Sand Sand Sand

0 0 0 0 0 0

Clay1 K 60

S 30
I 10

?

deposits

K 55
S 35
I 10

Clay1
RG35-145

Incised channels
on Cretaceous -
Neoporoterozoic
sediment

Analcime 10
K 30
S 40
I 20

erosional

Clay2

(from de Heinzelin, 1952)

weathered

detailed log on Fig.6

3 1 0'

K 0
S 80
I 20

Clay2

10 m 10 m 10 m 10 m

RG35-166
RG35-170

4 5 0'

?

K 30
S 20
I 50

Clay3

560'

610' RG35-176

Maximum Flooding
Surface (MFS)

RG35-183 K 0
S 30
I 70

Clay4

CRETACEOUS
CENOZOIC
unknown hiatus duration

700'

Weathered sediments

Cross-laminations

9 1 0'

Calcareous sediments

Silty sandstones

Sandy siltstones

Clayey siltstones

Claystones

K : Kaolinite (%)
S : Smectite (%)
I : Illite (%)

MBANDAKA 1
310': Potamocypris ? sp.1, Potamocypris ? sp.2,
Eucypris sp.1, Cyprintus ? sp., Cypridopsis sp. -
abundant charophytes (Grambastichara sp.)
PALEOGENE
450': Cypridopsis sp. PALEOGENE
560': Barren

GILSON 1
610'-700': Eucypris sp.
PALEOGENE

DEKESE
no Cenozoic fossils

SAMBA
no Cenozoic fossils

910': Ilyocypris compressa,
Ilyocypris lomamiensis
ALBIAN-CENOMANIAN

(from Le Maréchal, 1966 and Giresse, 1990)

Fig. 14.3 Logs and correlations of the boreholes Dekese and Samba, the wells Gilson 1 and Mbandaka 1 and the surrounding outcropping domains, Bat´k´ Plateaus (Koukouya Plateau) and
Kisangani area (Yangambi cliffs). Clay mineralogy of Samba and Dekese boreholes from Vanderstappen and Verbeek ( 1964 ). Location maps on Plate 2 and Fig. 14.7