Permo-Triassic Tectonic Maps of Africa

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Kungurian 275+-5Ma

Hercynian tectonism is near its end and Cape Fold Belt activity at an early stage. Late Hercynian movements are setting off shear zones into the African and Iberian continents (Doblas, 1991: Hoepffer et al, 2005 ) . The Djeffara (DJ, Gabtni et al, 2009)) and Sicani (SI) rifts may thus be narrow transtensional features along shear zones splaying from the Late Hercynian belt. These are infilled with shallow to deep marine strata tortuously connected over flooded platforms  to Tethys (Muttoni et al, 2009). Scotese et al, 2017 presents arguments against a Neotethys propogation into the region at this time, e.g. lack of rifting in the east, lack of flood basalts or ophiolites. An alternative model is that Sicily/Tunisia was  a localized region of failed hyperextension . 
The model adopted here for the Cape Fold Belt (CFB)  is that of Linol and de Wit (2021), who suggest that there was double subduction below Patagonia, including consumption of the Agulhas Ocean (AO)  separating Africa and Patagonia  The pre-drift position of the Falkland Islands is disputed but the fit supported here, mainly based on Kimmeridgian facies and tectonic correlations places it south of Natal, necessitating a bend in the Cape Fold Belt as it enters South Africa offshore. 

Southern and East African lineaments are after Macgregor (2018), who differentiates two phases of Permo-Trias rifting in southern Africa. The first of these is initiated in the Stephanian and reaches peak activity at this time (Catuneanu et al, 2005).  Narrow transtensional and deep half grabens are developed along the ‘Southern Trans Africa Shear’ from the Morondava Basin (MO) to the Aranos Basin (AB) of Namibia (Orpen et al, 1989, Miller, 2008). Another set of dip slip rifts, typified by the Rukwa (RU) rift, runs perpendicular to the main trend through Zambia and Tanzania. This constitutes a very similar pattern to the later association of Cretaceous rifts with the Central African shear. There is no clear connection to lineaments in South America but an intersect with the Cape Fold Belt is likely (Visser & Praekelt, 1995), perhaps in the current offshore.

Induan 250+-5Ma

The last of the collisions that assemble Pangea occurs as the main phase of the Cape Orogeny  (Linol and de Wit, 2016) . Distal compression is seen as far away as the Cuvette Centrale (CC; Giresse, 2005).  The Great Karoo Basin moves into a filled stage, characterized by non-marine sediments (Catuneanu et al, 2005) .  A northwards expansion of the Permo-Triassic rifts of eastern Africa occurs around this time, with rifts initiated over north-east Africa (Macgregor (2018). The main rift event in the Ogaden (OG) Basin is, for instance, of Early Triassic (Induan) age, during which a thick deep lacustrine shale (Bokh Shale) was deposited (Worku & Astin, 1992) , time equivalents of which are seen in the Mombasa Basin and Middle Sakamena Formation of the Morondava Basin in Madagascar. The correlation of Triassic rifts between Tanzania and Madagascar is an important element in defining the original fit between Africa and Madagascar (Reeves, 2016). Reeves fit has been slightly relaxed here for ease of display and to prevent overlaps of facies belts. Madagascan rifts again show more marine influence at this time than do the African ones, due likely to a marine inlet likely pulsating southwards from Tethys, perhaps through the Somalian offshore rifts mapped by Davidson et al (2018)

In North Africa the Djeffara (DJ) Rift is still subsiding (Gabtni et al, 2009) while other seemingly isolated set of rifts are forming in the Maragh (MA)  Basin and Hameimat (HA) Basins of Libya (Gras and Thusu, 1996 ). The Palymrides (PA) Basin of Syria (Brew et al, 2001) rifts as a precursor to opening of part of the Eastern Mediterranean and such activity could extend offshore into the Levantine Basin (Gardosh et al, 2006). The first rift that precedes Central Atlantic breakup occurs within the Argana (AR) Valley of Morocco (Frizon et al, 2008). Local rifting also occurs in the Sabratah Basin offshore Libya as part of a gradual step northwards of rift activity on this area through the Permo-Trias (Reeh, 2015).

Carnian 230+-5Ma

Neotethys may now be propagating into at least the northeastern part of the Mediterranean. This is evidenced by the outcropping of Late Triassic oceanic basalts in Cyprus (Lapierre et al 2006) and in Turkey (Robertson and Parlak, 2013). Israel (e.g. Judea Graben)  is still in a syn-rift phase however (Gardosh et al, 2006) and the North Eratosthenes Transform (NET) is speculated to form a limit to the Neotethyan ocean at this time.  Widespread carbonate deposition characterises the northern and north-eastern margins of the African (including Arabian) plate, though with an increasing proportion of deepwater facies (Dercourt et al, 2000).

There is a large expansion or initiation of rifting in the Atlas (AT) rifts (Le Roy & Pique, 2001: Manspeizer, 1988) , in the Newark (NE) rifts , presumably in their NW African conjugates, as well as in offshore Sicily (Catalano et al, 2013).  More gentle sag-like extension occurs in the Triassic Basin (TB) of Algeria , while rifting has also tentatively been interpreted on seismic in the Gulf of Sirt (GOS) and northern Cyrenaica areas (Gillard, 2017, PESGB Africa Conference presentation) . Rifting may thus be occurring over a wide belt from the Levantine Basin (LB) of Israel to Senegal at this time and many authors thus consider this the peak rifting period of North Africa  (Jagger et al, 2018).

Many of the rifts in southern Africa now seem to be in a phase of passive fill by fluvial redbeds (Macgregor (2018). Following a stratigraphic hiatus in the Ladinian which could mark the final movements on the Cape Fold Belt (CFB), the Great Karoo (GK) Basin appears to enter an overfilled phase (Catuneanu et al, 2005)

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