CENOZOIC (TERTIARY) PALEOTECTONIC AND PALEOGEOGRAPHIC MAPS OF AFRICA

DRAFT 1
An ongoing project using the plate model of Colin Reeves (www.reeves.nl)
Comments welcomed

Ypresian 50Ma

Key Events/Points
•Relatively quiescent period on all aspects – little tectonic activity, slow erosion, constant humid climate over much of continent high sea level , low sedimentation rates and consequential richness in carbonates
•1. Most significant activity seems to be a third phase of rift activity in Niger, affecting northern rifts as well as southern ones (based on sections in Genik, 1993)
•2. Sections in Iullemeden Basin show marine bands (Moody, 1997), indicative of marine input generally thought to be from north – shoreline based on Guiraud and Bosworth, 1999)
•3.Inversion in Chad (40-37Ma) shows Central African lineament active (D. Reynolds, pers comm)
•4. BX=bauxites. These are widespread across Africa at this time, indicating slow erosion and a constant humid climate (Burke and Gunnell, 2008) (Pearson et al 2007)
•5. Cutting of African Surface associated with these bauxites (Guillocheau et al 2017)
•6. Mid rifting in Sudan and the Anza Basin with the Melut Basin most active. Faults at this time show a more NNW-SSE trend. Alternating periods of rifting and inversion in central and southern Anza Basin (Morley et al, 1999)
•7. Niger Delta originated in Paleocene. Shows much higher sedimentation rates that any other deepwater area, suggesting that much of African drainage is focussed out of Benue system at this time (Macgregor, 2012), Niger itself not significant (Bonne, 2014)



Priabonian 35Ma

•Quiescent Eocene tectonics and climatic systems are interrupted by the Atlassic tectonic event and the onset of volcanism and rifting in Ethiopia and the Gulf of Aden
•1. Main Pyrenean Event and onset of main Alpine phase in western Alps (Handy et al, 2010)
•2. ‘Atlassic’ event coeval with Pyrenean event. Frizon et al, 2008. 2009 reports this as significant in Morocco, though it appears to be perhaps less so in Tunisia (Zouaghi et al, 2010)
•3. Further tectonic phase in Sabratah Basin and along Sabratah Fault (Boote, 2019)
•4. First volcanism in southern Ethiopia, 45-32Ma (Purcell, 2018)
•5. A few rifts may have become active in the Eocene in NW Kenya – dating of basal sections is incertain, particularly the Gatome and Lotikipi Basins (Purcell, 2018). These may well be linked to NNW-SSE rifting in the Melut Basin (Dou et al, 2007, )
•6. Climate assumed to be similar to Ypresian. Continued development of bauxites etc
•7.Inversion in Chad (40-37Ma) shows Central African lineament active (D. Reynolds, pers comm)

Rupelian 30Ma

•Climatic changes associated with onset of Antarctican glaciation are accompanies by the onset of various uplifts, causing a shift to clastics or an increase in sediment rate on many margins. Lowering of sea level. Many current drainage systems are initiated Initiation of EARS
•1. Nile River initiated at ca. 30Ma with probable route through Western Desert. Seemingly a response to uplift in Afar Plume area (Macgregor, 2012)
•2. Afar Plume uplift topography ca 1km (Sengor 2001). Flood basalts erupted at 31-30Ma (Purcell, 2017). Similar eruptions commence in Saudi Arabia, representing the plume that eventually led to breakup of the Red Sea (Stockli and Bosworth, 2019)
•3. Significant activity on Cameroon Line of volcanics initiiated at circa 30Ma (de Plaen 2013) . Increase in sedimentation rate and onset of prograding of Niger Delta (Macgregor, 2012)
•4.Congo river initiated over basal Oligocene unconformity , initially flowing out further south than at Present Day (Macgregor, 2012)
•5. Dispute amongst many authors on significance of Oligocene uplift of S African plateau (e.g. Burke et al, 2003). Model shown is largely after Moore et al (2009) suggesting an axis of uplift swinging round the Kalahari. Uplift also supported by significant basal Oligocene unconformity in many basins, particularly in Angola (Macgregor, 2012)
•6. Onset of rifting of Gulf of Aden. Unzips from east to west (Purcell, 2017). Drilling onshore has shown many onshore rifts to have a largely Oligocene fill
•7. Third major rift phase in Sudanese rifts (McHargue, 1992)
•8. Most likely start of rifting in northern Kenya and of first phase of EARS (Macgregor, 2015). South Lokichar Basin is probably earliest rift and is thought to be form at this time

Langhian 15Ma

•Significant increase in tectonic activity in northern Africa, particularly in interactions with European plates. Southern Africa relatively quiescent. Many plate events roughly synchronous
•1. Western Mediterranean opens around 22Ma, Kabylies collide with Africa around 18Ma commencing Tellian structural event (Carminati et al, 2012)
•2. Onset of subduction of Eastern Mediterranean around 15Ma(Le Pichon et al, 2019) . Stimulates inversion structures e.g. offshore Levantine Basin
•3. Main phase of Red Sea rifting and hinterland uplift around 20Ma (Bosworth et al 2005). Stimulates sediment delivery to Nile. Dead Sea transform initiated at 14Ma with abandonment of rifting in Gulf of Suez (Bosworth et al, 2005)
•4.Spreading now propagating from E to W through Gulf of Aden (Purcell, 2017)
•5. Neogene climates largely based on Senut et al (2009) and Griffin (2002), NW Africa believed to be substantially wetter than NE Africa with Egypt having fossil forests (Said, 1990)
•6. EARS rifting propagating southwards through Kenyan Eastern Branch. Aswa Fracture Zone initiated along with Albertine Basin at approx. 17Ma (Simon et al, 2017)
•7. Volcano-capped swells growing in Hoggar, Tibesti and northern Libya. Volcanic dates from Masous (2014).
•8. Drainage systems follow those in Oligocene. Significant uplifts will follow later in Miocene (Guillocheau et al, 2017)
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Zanclean 5Ma


•Activity building up to Present Day peaks in tectonics, climate variability, topography and erosion/sedimentation rates
•1. Strongest movements in the Atlas, commencing in the Serravallian-Tortonian and still active (Frizon et al, 2008, Said et al 2011)
•2. Volcanism on Saharan highs becoming more extensive. e.g. Garian, Al Haruj, Masoud (2014). Likely further topography growth, much of which may be reflected in high Niger river sedimentation rates
•3. At least seasonally wet period affects most of NE Africa (Macgregor, 2012, Griffin, 2002), maximum sedimentation rates in Nile Delta result.
•4. Spreading in S Red Sea , disputed whether this extended to northern parts, where may still be in a magma-poor hyperextended rate (Stockli and Bosworth, 2019)
•5. Large lakes developed in response to wetter climate, drawn after Drake et al (2008)
•6. Uplift over large areas of Central Africa from 11-3Ma after Guillocheau et al (2018) , include much of Cuvette Centrale
•7. Ethiopian rift probably connected through by 5Ma (Macgregor 2015), with peak uplift of rift shoulders
•8. Western branch propagates progressively south with associated volcanism, Malawi rift probably formed around 7Ma (Macgregor, 2015)
•9. Niger Delta at peak sedimentation rate (Macgregor, 2012), likely reflecting wet climate, though Guinean/Malian headwaters have yet to be captured (Bonne, 2014)

Holocene/Present Day 0Ma

•Peak of activity in almost all aspects, particularly max extent and intensity of EARS movements
• Serrated symbol=Recent significant earthquakes (after Meghraoui et al 2016). Faults shown as active are determined by this observed activity
•1. Further expansion of EARS, particularly Much of topography is very young (Macgregor, 2016)
•2. Final modifications to drainage systems. Upper Niger captures (Bonne,2014) as is Upper Zambezi and Victoria Nile (Macgregor, 2012)
•3. Climates become very variable (Burke et al 2003). Sahara formed at 2.5Ma and has expanded and contracted as shown since then. Significant savannah developed from around this time.