Overview of the Neoproterozoic Sedimentary Series Exposed Along Margins of the Congo Basin - Geology and Resource Potential of the Congo Basin - page 45

east, the Mesoproterozoic Karagwe-Ankole Belt to the
west and the Paleoproterozoic Ubendian Belt to the
south. Lithostratigraphically, the Malagarazi Supergroup,
stratigraphic-equivalent to the Bukoban Supergroup of
Tanzania, is divided into, from base to top (Tack 1995 ): (i)
the 290-890 m-thick siliciclastic and carbonate Musindozi
Group, resting unconformably on Burundian basements,
with minor intrusions of dolerite feeder sills of the Nyaganza
Basalts (Waleffe 1965 ; De Paepe et al. 1991 ) emplaced
between 709

extensions of amygdaloidal lavas within the BI group along
Kiankodi and Lovoy rivers, (Cahen and Mortelmans 1947 ).
Along the Kibaran Belt in the southern part of the basin, i.e.
the Kabele and Kabenga Conglomerates, with more than
50 % of clastic material derived from the Mbuji-Mayi
carbonates, were attributed to the Grand Conglom´rat For-
mation of the Katanga Supergroup (Cahen and Mortelmans
1947 ).

14 Ma (Deblond et al.
2001 ); (ii) the approximately 150 m-thick siliciclastic and
carbonate Mosso Group including 100 m-thick amygdaloi-
dal basalts at 815

2 Ma and 815

3.3.4.2 Local Luamba Group Linked to the
Mbuji-Mayi Supergroup
Ninove ( 1954 ) described, in the Lueo-Lubilash area
(Fig. 3.1 ), an approximately 800 m-thick sedimentary suc-
cession of the Luamba Group which they linked to either the
Mbuji-Mayi Supergroup or as they suggested may represent
a medium group between the Lubudi Group of the Kibara
and the Mbuji-Mayi Supergroup.

14 Ma (De Paepe et al. 1991 ); and (iii)
the 865 m-thick red-bed siliciclastic Kibago Group.

3.3.4 The Southern Margin of the CS

The late Mesoproterozoic and Neoproterozoic sediments
outcrop in two large regions of the southern margin of the
CS, each with its own characteristics (Robert 1956 ; Raucq
1957 , 1970 ; Fran¸ois 1974 ; Wendorff 2000 , 2005 ; Cailteux
et al. 2005 , 2007 ; Delpomdor and Pr´at 2013 ; Delpomdor
et al. 2013 ).

3.3.4.3 The Katanga Basin, DRC and Zambia
The Katanga Supergroup consists largely of tabular
metasedimentary sequences that extend from the DRC into
Zambia (Fig. 3.6A ). These sequences are affected by the
Pan-African or Lufilian north-directed folding and thrusting
deformations (c. 620-570 Ma; Kampunzu and Cailteux
1999 ), stretching over a 700 km-long and 50 km-wide region
from the Mwinilunga district in northwestern Zambia (Brock
1961 ; Steven 2000 ), east-northeastwards through Kolwezi
and Likasi (DRC), and southeastwards to Bwana Mkubwa
(Zambia) and Lonshi (Cailteux et al. 2007 ). In thrust-fold-
belt, regional metamorphism grades from amphibolite
prehnite-pumpellyite facies in the outer zones to lower
greenschist facies toward the inner zones (Ramsay and
Ridgeway 1977 ; Lefebvre and Patterson 1982 ). Lithostrati-
graphically, the Katanga Supergroup (Fig. 3.6B ) is divided,
from oldest to youngest (Cailteux et al. 2007 ) into: (i) the
Roan Group; (ii) the Nguba Group (formerly Lower
Kundelungu); and (iii) the Kundelungu Group (formerly
Lower Kundelungu). Wendorff ( 2000 , 2005 ) proposed an
alternative interpretation of the stratigraphy, with absence of
the Lower Roan in the DRC. This subject forms a matter of
intense discussion (e.g. Cailteux et al. 2005 ) beyond the
scope of this chapter. The 880-750 Ma Roan Group (Master
et al. 2005 ) is subdivided into four subgroups (Cailteux et al.
2007 ): (i) the

3.3.4.1 The Sankuru-Mbuji-Mayi-Lomami-Lovoy
Basin, DRC
The Sankuru-Mbuji-Mayi-Lomami-Lovoy Basin (SMLL;
Fig. 3.5A ) is located between the Archean-Paleoproterozoic
Kasai Craton to the north and west, and along the
Mesoproterozoic Kibaran Belt to the south and east (see
also Delpomdor et al. 2014 ). The Mbuji-Mayi sedimentary
sequence is weakly or no affected by regional metamor-
phism (Polinard 1935 ; Wasilewsky 1954 ; Cahen 1954 ;
Raucq 1970 ). The Mbuji-Mayi Supergroup (Fig. 3.5B )is
divided as follows, from oldest to youngest (Raucq 1957 ,
1970 ): (i) 550 m to 3,000 m-thick siliciclastic 1174

22 Ma

to 882.2 8.8 Ma BI group (Cahen 1954 ; Holmes and

Cahen 1955 ; Delhal et al. 1966 , 1989 ; Delpomdor et al.
2013 ) unconformably overlying the approximately
3.0-2.5 Ga metamagmatic rocks of the Dibaya Complex to
the north (Delhal et al. 1976 ; Cahen et al. 1984 ; Delhal 1991 ;
Key et al. 2001 ; Batumike et al. 2009 ); and (ii) 1,000 m-thick
carbonate 810 Ma BII group (Delpomdor et al. 2013 )

including stromatolitic bioherms (Bertrand-Sarfati 1972 )
with local shales. Two important masses or bodies of basalts
are reported in the basin: (i) basaltic lavas, they yielded an
altered age of 948

(R.A.T.;
undeterminated thickness) reported stratigraphically to the

' Roche Argilo-Talqueuse Subgroup '

880 Ma Mindola Subgroup in Zambia (Armstrong et al.
2005 ); (ii) the 400 m-thick carbonate Mines Subgroup

correlated with the Kitwe Subgroup in Zambia; (iii) the
>

>

20 Ma (Cahen et al. 1974 ) and overlie
the BII group at the confluence of the Mbuji-Mayi and
Sankuru rivers (Cahen et al. 1984 );

1,000 m-thick carbonate Dipeta Subgroup equivalent to
the Kirilabombwe Subgroup in Zambia (Cailteux 1994 ;
Cailteux and Kampunzu 1995 ); and (iv) the 600-800 m-
thick carbonate and siliciclastic

(ii) doleritic sills

emplaced, at 888.2 8.8 Ma (Delpomdor et al. 2013 ),

close to the contact between the BI and BII groups in the
Lomami area; and (iii) undated sills of dolerite with large

760 Ma Mwashya Sub-
group (formerly Upper Mwashya; Armstrong 2000 ; Liyungu