Geology Reference
In-Depth Information
Ma
TECTONO-CLIMATIC SEQUENCES
Congo Basin
Parana Basin
0
AFRICA
SOUTH AMERICA
North
South
North
South
8
7
6
5
4
GLACIAL
50
KALAHARI
Kalahari
Epeirogeny
6
KWANGO
BAURU
100
LOIA / BOKUNGU
5
Parana-
Etendeka LIP
DEKESE
BOTUCATU
150
STANLEYVILLE
Hiatus: 50 Ma
Karoo LIP
Hiatus: 25 Ma
200
3
4
Cape Fold Belt
Orogeny
HAUTE-LUEKI
SANTA MARIA
250
Choiyoi
Sanrafaelic
Orogeny
2
3
300
LUKUGA
ITARARE / GUATA / PASSA DOIS
Chanic
Orogeny
GLACIAL
350
Hiatus: 50 Ma
Precordilleran
Orogeny
400
2
PARANA
Hiatus: 150 Ma
Ocloyic
Orogeny
1
450
GLACIAL
RIO IVAI
500
1
LINDIAN
Pan African
Orogeny
Brasiliano
Orogeny
δ
18
O
550
18
O curves
from Veizer et al. (
2000
), highlighting main episodes of glaciation
(
blue shades
)
Fig. 13.2
Compared Phanerozoic stratigraphic sequences of the CB
and PB (
circled numbers
on the
left
and
right
, respectively), and
correlation with regional tectonic and magmatic events of southwest
Gondwana (adapted from Milani and de Wit
2008
), and
δ
The PB is a 1.5 million km
2
, N-S elongated basin of west
Gondwana (Fig.
13.1
). It is flanked to the north by Precam-
brian basement (e.g. the Sao Francisco Craton) and to the
southwest by the Andes and proto-Andes, constructed above
the long-lived (~600 Ma) paleo-Pacific margin of southwest-
ern Gondwana (e.g. Ramos and Aleman
2000
). The PB
preserves six main depositional sequences (supersequences),
ranging in age from Late Ordovician to Late Cretaceous,
with a total thickness of about 7 km (Milani et al.
2007
). The
first two sequences comprise the Ordovician-Silurian Rio
Iva´ and the Devonian Paran´ Groups (Sequences 1 and 2;
Fig.
13.2
), in total 1,500 m thick. These lowermost
successions correspond to two superimposed shallow marine
platform sequences, similar (but thinner) to the lower Paleo-
zoic section of the Cape Supergroup in South Africa (Milani
and de Wit
2008
). Overlying a major erosional surface that
represents a hiatus of about 50 million years, the succeeding
Carboniferous-Permian succession (Sequence 3; Fig.
13.2
)
comprises up to 2,500 m thick glacio-marine to progres-
sively fluvial sedimentary rocks, attributed to the Itarar´,
Guat
´
and Passa Dois Groups (Schneider et al.
1974
).
These sequences are equivalent of large parts of the Karoo
Supergroup of southern Africa (e.g. Veevers et al.
1994
;
Milani and de Wit
2008
). Three overlying Mesozoic
sequences: the Santa Maria, S
˜
o Bento and Bauru Groups
(Sequences 4 to 6; Fig.
13.2
) correspond to 1,000 m thick
stratigraphic record comprises five major depositional
successions (or supersequences) ranging in age from late
Neoproterozoic to Cenozoic, with a total thickness of 4-6 km
in the center of the basin (Cahen
1954
; Lepersonne
1974
;Daly
succession (Sequence 1; Fig.
13.2
), part of
the upper
Neoproterozoic-lower
Paleozoic
Lindian
Supergroup,
comprises extensive
, between 1,000 and 1,500 m
thick, covering deformed Neoproterozoic (Pan African) car-
bonate and siliclastic platforms (Lepersonne
1974
; Poidevin
1985
). Overlying a major unconformity that represents a hiatus
of up to 150 million years, the two succeeding successions,
Carboniferous-Permian, and Triassic (Sequences 2 and 3,
respectively; Fig.
13.2
), totaling 900 to 3,000 m in thickness,
represent the northernmost extension of the classical Karoo
Supergroup of southern Africa (Cahen and Lepersonne
1978
;
Cahen
1981
). An overlying Mesozoic succession, defined as
the Congo Supergroup (Chap.
8
, this Topic), is between 300
and 1,000 m thick and comprises four sequences (Sequences
4 to 7; Fig.
13.2
) from shallow marine (tidal), to aeolian,
lacustrine, and then fluvial. This Upper Jurassic to Upper
Cretaceous succession is in turn truncated by a regional
peneplanation surface and covered by silcretes, calcretes
and alluviums of the Cenozoic Kalahari Group (Sequence
8), with a maximum thickness of 250 m in the center of the
basin (Chap.
10
, this Topic).
'
red-beds
'
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