Overview of the Neoproterozoic Sedimentary Series Exposed Along Margins of the Congo Basin - Geology and Resource Potential of the Congo Basin - page 40

Fig. 3.2 Western margin of the Congo Shield. (A) Sketched geologi-
cal map of the West Congo Belt (modified after Frimmel et al. 2006 ).
(B) Synthetic stratigraphic log combined with C and Sr isotopic curves
of the West Congolian Group in the DRC (modified after Tait et al.
2011 ). Note strontium isotope ratios of the Haut-Shiloango Subgroup
ranging between 0.7068-0.7072 (Frimmel et al. 2006 ; Poidevin 2007 )
and of the C3 to C5 formations of the Schisto-Calcaire Subgroup
ranging between 0.7074 to 0.7084 suggesting deposition, respectively,
between 800 Ma and 650 Ma and between 635 and 575 Ma (Frimmel

negative shift of , consistent, in absolute values, with the

negative swing of the Trezona anomaly (Halverson et al. 2007 ).
(C) Synthetic stratigraphic log combined with C and Sr isotopic curves
of the West Congolian Group in Gabon (modified after Thi´blemont
et al. 2009 ). Note slightly more negative

13

‰

13 C in the cap carbonate

δ

reported as typical (Pr´at

et al. 2011 ). (D) Synthetic stratigraphic log of West Congolian Group in
the RC (modified after Alvarez 1995 ). (E) Synthetic stratigraphic log of
West Congolian Group in Angola. cc cap carbonates; SG Sturtian

' Marinoan ' cap ranging form 1 to 5

‰ ‰