CRETACEOUS PALEOTECTONIC AND PALEOGEOGRAPHIC MAPS OF AFRICA
DRAFT 2 FEB 22
An ongoing project using the plate model of Colin Reeves (www.reeves.nl)
Comments welcomed
Late Valanginian-Early Hauterivian 135Ma
Key Events/Points
•
•
•1 Plate seemingly under NE-SW tension
throughout with many NW-SE rifts initiated
•2.. Expansion of CARS system westwards
from Blue Nile Basin to incorporate Muglad etc (note well before Atlantic spreading), Genik
1993, McHargue,
1992)
•3. Transtensional
basin formation also propagating west from Marajo Basin in Brazil (Costa, 2002,
Ye, 2017) Also initiation of e.g. Araripe
(Batista, 2017) and Potiguar
Basins (Milani,
2007)
•4. First mild rift phase(Afro-Brazilian
depression) in Reconcavo-Gabon
area but not connected to southern South Atlantic (Chaboureau,
2012)
•5. Agulhas transform now pulling open
southern extreme of South Atlantic. First oceanic crust S of Orange Basin
(Macdonald, 2013; Franke, 2013)
•6. Parana-Etendeka volcanics peak in Hauterivian and seemingly pass into SDRs along
Namibia and Uruguay margins (Macdonald, 2013; Franke, 2013)
though some recent dates extend into Valanginian
•7. Start of weak Eo-Alpine
compression on northern margin of Adria (Handy, 2010)
•8. Third and final phase of rifting of
Western Desert following period of uplift and of volcanism in Israel (Dolson,
2014)
Barremian 130Ma
•1. AFTA data indicates Reguibat and Meseta
rising and eroding (Bertotti,
2019) : carbonates changing to thick clastic succession in S Mauritania at this
time (Kosmos
presentations)
•2. End of spreading of Ligurian
Ocean with initiation of subduction below Alkapeca/Iberia (Handy, 2010)
•3. Southern Sirt
rifts (E-W trending) active (Hallett, 2016). Speculation that NW-SE branches
may be becoming active (no data at depth)
•4. Marajo Basin active as pull-apart
connected to transform likely connected to Ghana (Costa, 2002, Ye, 2017)
•5. Dextral transforms in Brazil/Cameroon
according to Popoff
(1998) . Some form northern terminations of S Atlantic rifts. Benue Trough faults reported however as sinistral
suggesting that intervening block active as separate platelet
•6. Peak of rifting across South Atlantic
Basins. Passing into sag sequences in Late Barremian (Chaboureau, 2012)
•7. End of SDRS in Namibia. Breakup of
northern Namibia possibly termining at Mwembishi FZ extension (Franke, 2013)
Aptian 118Ma
•Period of plate reorganisation and major
tectonic activity across nearly all areas of the African plate
•1. Major shift westwards and peak in Eo-Alpine
orogeny on northern rim of Adria. Bay of Biscay rotating Iberia against NW
Africa with subduction of Ligurian Ocean (Handy, 2010)
•2. ‘Austrian’ event of Late Aptian.
Dextral faulting and transpression on
old lineaments. Widepread
uplift (shown as topography) and deep erosion surface over Libya as far east as
Cyrenaica (Boote,
1998, Coward, 2003)
•3. Peak rifting in Sirt
Basins, including Gulf of Sirt (Boote, 1998)
•4. Sirt rifts parallel Malta and to some extent
Apulia escarpments. A number of authors suggest rifting prior to some slow
(?re?) opening of the Ionian Sea (Jagger, 2018, Handy, 2010)
•5. Niger rifts now spreading northwards (Genik,
1992, sections). Start of main rift phase with close correlation to events in
the Sirt
Basin (Blaisse,
2019)
•6. Deep transtensional
basins and lakes form and expand on Equatorial margins of Brazil and Africa
(Teasdale, 2019, Antobreh,
2009, Ye, 2017. In most basins, Aptian is thought to be oldest sediments.
Probably final connection of system through to CARS
•7. Salt over most South Atlantic basins
from 118-114 Ma (Chaboureau,
2012). Above possible break-up unconformity at 122Ma . Hatching shows lithology
above and below this unconformity, i.e. Late and Early Aptian. Was salt coeval
with spreading ridge?
•8. Madagascar stops going southwards
quite soon after M0. That makes it about
125 Ma on the IUGS2020 chart, though 118 Ma seems to have worked its way into
folklore over many decades. The new
Elsevier chart, however, has this event (base Aptian) suddenly at 121 Ma.
Somali Ocean spreading now terminated
•9. First period of uplift of South
African plateau, concentrated in south (Baby, 2018)
Late Albian 102Ma
•1. Northern part of South Atlantic
(northern Gabon northwards) breaks up in Early Albian . SDRs in northern Gabon and
Sergipe Basin
(Fullarton, 2019)
•2. Arid climate at this time, so Congo
not a major sediment deliverer. Pinda Sst of Cabinda and fan interpreted on
seismic is first generation of Congo river (Anka, 2010, 2014)
•3. Anza rifting Growth of rift shoulders and uplift on
Tanzanian Craton feed first major fans on Tanzanian margin. (Foster, 1992,
Noble, 1997)
•4. Rivers feeding fans in Bradasdorp
Basin (Brulpadda
discovery : ponded vs Diaz transpressional
arch)
•5. Two ‘break-up’ unconformities are
recorded on the Eq
Margin. – late mid Albian, representing first local formation of oceanic crust
and 100Ma, representing full separation of plates (Antobreh,
2009, Dailly,
2012)
•6. Expansion of Orange river and start of
prograding (Jungslager,
1999)
.
Santonian 86Ma
•1. Senegal and S Mauritania rivers seem
to become inactive. Late K input is coming in from Reguibat in
N. Mauritania. Major unconformity offshore Senegal
•2. High sea level throughout Late K
mapped by Bonne, 2014. Marine sediments cover Palaeozoic basins of Libya and
Algeria as well as Iullemeden
Basin of Mali
•3. Second (mild ) rift phase in Sudan (Mchargue,
1992) (contrasts with sag tectonics in Niger)
•4. Jesomma Fm. clastics input to Somaliland and Ethiopia
indicate a local uplift (Ali, 2019)
•5. Rivers on Eq
Margin though to be maturing up the interval (Macgregor, 2003). Major system in
particular develops as Abeokuta delta on Benin-Nigeria border
•6. Mild reactivation of rifts in Late
Cretaceous north Africa such as Gabes and Sabratah Basins. Likely transtensional (Reeh,
2015, Mriheel,
2015). It is probably unlikely such mild movements are capable of opening the Sirt
Basin as suggested by Anketell,
(1996)
Maastrichtian-Danian 65Ma
•Relatively quiescent period
•1. India completes its split from the
Seychelles and is rapidly migrating to NW, possibly still putting NE-SW stress
on northern Africa
•2. Extension is now dying out across the
CARS with all basins in a post-rift phase prior to Palaeogene reactivations (Genik,
1993, Mchargue
(1992). The Niger rifts undergo a period of uplift and erosion
•3. Abeyance of Pyrenean events in Atlas
prior to main Atlassic
phase in Eocene (Handy, 2010)
•4.Reactivation of Syrian Arc inversions
in Egypt (Bevan, 2012) (but not apparently in Benue Trough, although there is
some disagreement between authors, Whiteman, 1982)
•5. Due to uplift in Niger, periodic
marine inlets are pushed westwards to the Taoudenni and Iullemeden basin (Bonne, 2014)