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(Modified after Raucq
1957
,
1970
). Note the
87
Sr/
86
Sr ratios ranging
between 0.7069 and 0.7071 and the negative
Fig. 3.5
Southern margin of the Congo Shield. (A) Sketched geologi-
cal map of the Sankuru-Mbuji-Mayi-Lomami-Lovoy Basin (modified
after Raucq
1957
,
1970
). (B) Synthetic stratigraphic log combined with
C and Sr isotopic curves of the Mbuji-Mayi Supergroup in the DRC
13
C shifts of 4.0
and
δ
‰
6.1
in the BIIb and BIIc transition, which are reported with the
Bitter Springs anomaly around c. 810 Ma (Delpomdor et al.
2013
)
‰
et al.
2001
; Key et al.
2001
; Barron et al.
2003
) including
mafic volcaniclastic rocks (Lefebvre
1973
; Cailteux
1983
;
Cailteux et al.
2003
; Kabengele et al.
2003
) coeval with the
gabbroic bodies emplaced within rocks of the Dipeta Sub-
group (DRC) and Bancroft-Kanwangungu formations
(Mendelsohn
1961
; Lefebvre
1975
; Cailteux et al.
2007
).
Cailteux et al. (
2007
) adopted a similar lithostratigraphic
scheme for the Upper Katanga Supergroup, i.e. the Nguba
and Kundelungu groups, between the DRC and Zambia.
The
2,000 m-thick Nguba Group comprises a shaly car-
bonate succession becoming siliciclastic at the top, and is
subdivided into (i) the Muombe Subgroup including the
diamictitic 765-735 Ma
Grand Conglom
´
rat
or Mwale
Formation (Key et al.
2001
; Wendorff and Key
2009
)
correlated with the global Sturtian glacial event (Cailteux
et al.
2007
); and (ii) the carbonate and siliciclastic Bunkeya
Subgroup. The Kundelungu Group is further subdivided
into: (i) the Gombela Subgroup including the glacigenic
'
'
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