New Regional Correlations Between the Congo, Parana´ and Cape-Karoo Basins of Southwest Gondwana - Geology and Resource Potential of the Congo Basin - page 248

Fig. 13.9 Carboniferous glacial pavement at Witmarsum, southwest Paran´. Large groove marks ( double sided arrows ) onto the Furna Formation
indicate N-S advances and retreats of the ice cap

Feliciano-Damara Belts along the southeastern margin of the
basin (see Fig. 13.3 ). Thus, the detrital zircons provenance
ages from the Itarar´, Dwyka and Lukuga Groups, together
with the sediment and ice-flow dispersion directions indicate
a long wavelength Carboniferous topography across south-
west Gondwana dominated by the Cargonian and Tanzanian
Highlands (Fig. 13.10 ). These paleo-highs generally coin-
cide with central remnants of Braziliano and Pan African
orogens.
Subsequent rapid deglaciation during the Early Permian
resulted in a short-lived marine transgression across south-
west Gondwana and, following isostatic rebound, extensive
deposition of shallow water, organic-rich black shales
(Visser 1995 ; Scheffler et al. 2003 ; Frank et al. 2008 ;
Monta˜ez and Poulsen 2013 ). In the PB, the Permian
Guat´ and Passa Dois Groups (maximum 2,600 m thick),
comprise in the lower part vast low-stand deltas prograding
southward (the Rio Bonito Formation) and notably thick
bioturbated siltstones of the Palermo Formation that record
a final maximum marine transgression during the Artinskian
(e.g. Souza 2006 ; Milani et al. 2007 ; Fig. 13.6 ). It is sharply
overlain by 40-70 m thick, organic-rich black shales of the
Irati Formation, U-Pb dated with igneous zircons from
interbedded ash beds (tungsten) at ca. 278

South Africa for the first time by du Toit ( 1927 ), and which
is now confirmed by zircons accurately dated between
275-279 Ma from similar ash interbeds within the Whitehill
Formation across southern Africa. This chronostratigraphy
supports the occurrence of an extensive '

lake across southern Africa and southern South America at
the end of the Early Permian (Fig. 13.10 ). In the CB of
central Africa, the Lukuga Group also includes significantly
thick Permian black shales (e.g. the Lukuga Formation) and
sandstones with thin coal beds (Cahen and Lepersonne
1978 ). Although the litho- and bio-stratigraphy are not
well-enough constrained to propose more detail correlations
(see Fig. 13.6 ), it is likely that the gigantic Early Permian
lake may, at times, have extended as far north as the CB
(Fig. 13.10 ).

' Black Sea-like

13.4.2.2 Late Permian-Triassic
Permian-Triassic sedimentation across southwest Gondwana
became entirely continental and arid (e.g. Veevers et al.
1994 ) and was associated with widespread arc-volcanism
and magmatism along the proto-Andes (e.g. Ramos and
Aleman 2000 ). This extensive silicic magmatic belt
(Fig. 13.11 ) comprises the Permian-Triassic Choiyoi Igne-
ous Province in Chile and Argentina, and the Triassic to
Middle Jurassic Chon Aike Province in Patagonia (Kay

3 Ma (Santos
et al. 2006 ). This distinct (condensed) Irati sequence was
correlated biostratigraphically to the Whitehill Formation of