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Fig. 9.1
SRTM model showing location of Congo Basin, occupying
much of the Democratic Republic of Congo (DRC), along with portions
of the Republic of Congo (Congo-Brazzaville, RCB), Central African
Republic (CAR) and Angola. Note in the close up view the position of
deep cores in the Cuvette Centrale and
black box
showing the study
area in the Kasai portion of the basin
summarized as preliminary mapping during and shortly after
the colonial Belgian Congo years (Cahen and Lepersonne
1951
,
1954
,
1978
; Cahen
1954
; Raucq and Lepersonne
1966
; Raucq
1979
), coupled with early geophysical
explorations (
ยด
vrard 1957; Jones et al.
1960
) that culmi-
nated with the drilling and detailed analysis of two deep
boreholes in the central portion of the basin (Samba and
Dekese wells, Figs.
9.1
and
9.2
; Cahen et al.
1959
,
1960
).
During and following this interval, most of the work in the
basin focused on paleontological investigations of modest
microfossil and fish faunas recovered from the wells and
elsewhere in the basin (de Saint-Seine
1952
,
1953
,
1955
;
Grekoff
1957
,
1958
,
1960
; Cox
1960
; de Saint-Seine and
Casier
1962
; Defretin-Lefranc
1967
; Taverne
1976
,
1984
;
Cahen and Lepersonne
1978
; Cahen
1983
; Colin
1994
).
After the colonial mapping and exploration, the only signifi-
cant new investigations in the basin have been the oil and gas
exploration programs by Esso and Texaco in the Cuvette
Centrale during the mid-1970s to early-1980s. This work
included acquisition of a modest amount of magnetic and
2-D reflection seismic data, along with the drilling of two
deeper boreholes (Gilson and Mbandaka wells; see Figs.
9.1
and
9.2
) into the deepest parts of the basin (Lawrence and
Makazu
1988
). Our best insight into the tectonics and deep
structure of the basin comes from a seminal basin synthesis
and interpretation of some of this data by Daly et al. (
1992
).
In an attempt to better comprehend the sedimentary and
tectonic evolution of the greater Congo Basin, the distri-
bution, depositional environments, and structural controls
on Mesozoic and Cenozoic cover sequences (particularly
outside of the Cuvette Centrale), a study was conducted of
borehole cores and logs made available from an extensive
drilling program in the Kasai region of the Congo Basin in
south-central DRC and northern Angola by De Beers Explo-
ration (Fig.
9.3
). Sedimentological data from 22 complete
exploration boreholes (cores) and investigation of surface
exposures in the area are presented herein (Fig.
9.3
). The
purpose of this paper is to apply detailed facies analysis,
coupled with detrital zircon geochronology and paleontological
investigation of the Mesozoic cover sequences along the
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