Sh8 Fm
Period:
Cryogenian
Age Interval:
650–655 Ma
Province:
West Congo Basin / Bas-Congo region, DRC
Type Locality and Naming
Synonym:
Reference section:
Lithology and Thickness
dark-grey clayey nodular limestone, stromatolitic limestone, limestone breccia at top. Open marine carbonate platform (Sekelolo unit). Thickness: 200–350 m (Sekelolo unit).
Lithology Pattern:
Clayey limestone
Relationships and Distribution
Lower contact
Underlain by the Sh7 Fm.
Upper contact
Overlain by the Upper Diamictite (former 'Mixtite') Fm.
Regional extent
West Congo Belt (DRC, Republic of Congo, Gabon, NW Angola).
GeoJSON
{"type":"Feature","geometry":{"type":"MultiPolygon","coordinates":[[[[10.77,-1.12],[10.9,-1.26],[10.96,-1.41],[10.97,-1.63],[10.99,-1.85],[11.12,-2.02],[11.48,-2.31],[11.78,-2.6],[12.05,-2.82],[12.39,-3.13],[12.86,-3.54],[13.07,-3.66],[13.34,-3.84],[13.56,-3.98],[13.89,-4.3],[14.16,-4.74],[14.24,-5.01],[14.26,-5.32],[14.31,-5.76],[14.41,-5.98],[14.57,-6.31],[14.78,-6.6],[14.99,-6.9],[15.23,-7.22],[15.58,-7.85],[15.64,-8.08],[15.62,-8.5],[15.5,-8.7],[15.19,-8.87],[14.89,-8.84],[14.67,-8.73],[14.55,-8.45],[14.33,-8.11],[14.16,-7.75],[13.95,-7.59],[13.75,-7.36],[13.69,-6.93],[13.68,-6.68],[13.65,-6.33],[13.51,-6.04],[13.39,-5.67],[13.3,-5.34],[13.15,-5.06],[12.98,-4.81],[12.83,-4.72],[12.61,-4.59],[12.44,-4.39],[12.26,-4.27],[11.96,-4.02],[11.8,-3.76],[11.59,-3.65],[11.32,-3.51],[11.21,-3.36],[11.37,-3.32],[11.51,-3.21],[11.24,-2.97],[11.07,-2.82],[10.87,-2.52],[10.71,-2.14],[10.66,-1.92],[10.64,-1.57],[10.64,-1.29],[10.73,-1.18],[10.73,-1.18],[10.73,-1.18],[10.77,-1.16],[10.77,-1.16],[10.77,-1.12]]]]}}
Fossils
Stromatolites (in Sekelolo limestones).
Age
Interpolated by thickness between 650–694 Ma
Age Span:
Beginning stage:
Cryogenian
Fraction up in beginning stage:
0.82
Beginning date (Ma):
650.30
Ending stage:
Cryogenian
Fraction up in the ending stage:
0.77
Ending date (Ma):
654.55
Depositional setting
Post-Sturtian open marine carbonate platform; two transgression-regression cycles (Cahen, 1954; Frimmel et al., 2006).
Depositional pattern:
Additional Information
Compiler:
Cailteux, J.L.H., Delpomdor, F.R.A., & Ngoie Ndobani, J.-P. (2015). The Neoproterozoic West-Congo 'Schisto-Calcaire' sedimentary succession from the Bas-Congo region (Democratic Republic of the Congo) in the frame of regional tentative correlations. Geologica Belgica, 18/2-4, 126–146.