New Regional Correlations Between the Congo, Parana´ and Cape-Karoo Basins of Southwest Gondwana - Geology and Resource Potential of the Congo Basin - page 251

et al. 1989 ; Kleiman and Japas 2009 ). In adjoining sub-
Andean basins, well-preserved ignimbrites, recently dated
between 250-280 Ma, characterize the main period of vol-
canic activity (Rocha-Campos et al. 2011 ) and, as a result,
the large number of air-fall tuffs reported with this age-range
in the PB and the CKB are generally attributed to this same
source (e.g. L ´ pez-Gamund ´ 2006 ).
In the PB, the Early Permian Irati Formation is overlain
by transgressive black shales (the Serra Alta Formation),
850 m thick siltstones of the Teresina Formation and
650 m thick southward prograding delta fronts of the Rio
do Rastro Formation (Milani et al. 2007 ; Fig. 13.6 ). This
thick regressive section is similar to that of the Upper Ecca
and Beaufort Groups in the CKB (Milani and de Wit 2008 ),
deposited with paleocurrents largely to the north from the
rising Cape Fold Belt, ca. 245-278 Ma (Cole 1992 ; Newton
et al. 2006 ; Tankard et al. 2009 ). Late Permian-Triassic
sedimentation then culminated in fluvial-aeolian and playa-
lake (arid) red-bed deposits both in the PB, with the
Piramb ´ ia, Corumbata ´ , Sanga do Cabral Formations and
the Santa Maria Group (Assine et al. 2004 ; Zerfass et al.
2004 ; Milani et al. 2007 ), and in the CKB, with the Molteno,
Eliot and Clarens Formations (Johnson et al. 2006 ). These
arid sequences are also equivalent to the Omingonde Forma-
tion in Namibia (Miller 2008 ) and the Mosolotsane Forma-
tion in Botswana (Bordy et al. 2010 ). By contrast, in central
Africa the Triassic sequences (the Haute Lueki and
Cassange Groups) are less precisely known, but have been
shown to be relatively thick (500-1,400 m) in the center of
the CB (Linol 2013 ; Chap. 7 , this Topic) and, most likely
also represent arid, fluvial and aeolian equivalents of the
Brazilian red-beds (Fig. 13.11 ).

conformably overlain by Lower Cretaceous lavas of the
Serra Geral Formation (Fig. 13.12 ).
These Upper Jurassic to Lower Cretaceous aeolian
sequences (also

' '

) that pre-date the extrusion of
the Paran´-Etendeka LIP imply an immense (

red-beds

2.5 million

>

km 2 ), paleo-desert near the center of West

Gondwana just prior to the opening of the South Atlantic
(Fig. 13.13 ). U-Pb detrital zircons geochronology from this
aeolian sequence in the CB (Linol 2013 ; see Chap. 8 , this
Topic) dated some Permian-Triassic (ca. 200 Ma and
240-290 Ma) and Jurassic (ca. 190 Ma) zircons, most likely
derived from the proto-Andes, as for the Permo-Carboni-
ferous air-fall tuffs reported in the PB and CKB (e.g. Fildani
et al. 2009 ; Rocha-Campos et al. 2011 ). However, the paleo-
wind directions measured from aeolian dunes in the south-
west CB and in the northern PB are northerly, opposite in
direction of the source for the wind-blown zircons from the
proto-Andes. We interpret this to reflect complex atmo-
spheric circulation regimes where high-atmosphere winds
responsible for the ash fall deposits blow to the north, from
the proto-Andean margin of southwest Gondwana toward
Tethys, whilst strong south-directed winds were blowing
close to the surface (see Fig. 13.4 ).
In the CB, the Upper Jurassic to Lower Cretaceous aeo-
lian sequence (the Dekese Formation; Fig. 13.6 ) is sharply
overlain by two superimposed, Albian-Cenomanian (middle
Cretaceous) successions of lacustrine deposits, corres-
ponding to the Loia and Bokungu Groups (Cahen 1983a ),
in total 650 m thick. These two singular (more humid) and
fossiliferous sequences can be correlated to syn-rift marine
sequences covering the thick Aptian salt along the west-
African Atlantic margin (e.g. Mounguengui et al. 2008 ),
but have apparently no equivalents in the PB. In southeastern
Brazil, the 132 Ma basalts of the Serra Geral Formation are
directly overlain by 200-300 m thick fluvial sediments of the
Upper Cretaceous Bauru Group (de Paula e Silva et al.
2009 ), which is now correlated by biostratigraphy to the
Upper Kwango Group in the western CB (Gobbo-Rodrigues
et al. 2003 ). This renewed Late Cretaceous fluvial sedi-
mentation both in the CB and PB may related to marginal
uplifts and erosion following rifting of the South Atlantic
(Fig. 13.14 ).

' Sahara-like '

13.4.3 Late Mesozoic to Cenozoic

13.4.3.1 Late Jurassic-Cretaceous
The Triassic sequences of the CB and PB (the Santa
Maria and Haute Lueki Groups) are truncated by regional
unconformities, and overlain by Jurassic-Cretaceous
sequences (Fig. 13.6 ). In the CB, the Upper Jurassic Stanley-
ville Group comprises 400 m thick shallow marine to fluvial
sediments (Cahen 1983b ; Linol 2013 ), and intercalates in the
lower part with a thin carbonate horizon ( 13.4.3.2 Cenozoic

Cenozoic terrestrial sedimentation is generally condensed in
south-central Africa (Linol 2013 ; Chap. 10 , this Topic). In
the CB and on top of the Kalahari Plateau, the Jurassic-
Cretaceous sequences (e.g. the Kwango Group) are trun-
cated by a regional peneplanation surface well-marked by
duricrusts (calcretes and silcretes), and in turn covered by
alluvial sands and muds of the Kalahari Group, maximum
250-500 m thick. Similar pedogenic carbonates and calcrete
deposits have also been described in the southern PB (e.g.
the Queguay Formation; T´falo and Pazos 2010 ), and thus

) with
fish fossils that record a short, Kimmeridgian marine trans-
gression of the proto-Indian Ocean in the northeastern part of
the basin (Taverne 1975 ). It is onlapped to the south by
aeolian dunes, maximum 300 m thick in the center of the
CB (the Dekese Formation; Chap. 8 , this Topic), which
extend along the southwest margin of the basin as the
Lower Kwango Group, into Namibia (the Etjo/Twyfel-
fontein Formation; Jerram et al. 1999 ; Miller 2008 ), and in
eastern Brazil as the Sergi and Botucatu Formations (Scherer
and Goldberg 2007 , 2010 ).

' Lime Fine '

In the PB the latter is