Articulated Africa
![Cretaceous Reshaping]()
A lot of plate-scale tectonic changes took place in a short time interval in the Early Cretaceous. The clockwise 'unwrapping' of other fragments of Gondwana from around Africa accelerated as India and Madagascar started to break out from their position between Australia, Antarctica and Africa by rotating anti-clockwise. (Greater) India started to separate from Antarctica-Australia, evidenced by marine magnetic anomalies off Perth, Australia - at 142.3 Ma in this model. Within a confined space, the NW margin of the India plate became an arcuate dextral strike-slip feature on the present-day alignment of the Owen Fracture Zone off Arabia-Somalia. With India still attached to Madagascar, the latter adopted a similar movement against Africa with the Davie Fracture Zone adopting a new, arcuate form and going into compression. Elsewhere, rapid ocean growth in the Weddell Sea started at about 142.3 Ma. From about this time the Mwembishi Fault Zone of southern Africa (black dashed line) executed slight dextral movement, making slightly more room for India and Madgascar to rotate.
Also at this time, the scissor-like opening of the southernmost South Atlantic Ocean started. This lead eventually to a clockwise rotation of the main body of South America, pushing northern Africa clockwise with dextral strike-slip faulting extending from Nigeria to Sudan with rifting (indicated schematically with green lines) entending SE into South Sudan. By about 117 Ma, Madagascar had come to rest as part of the Africa plate with India still attached.
With the South Atlantic Ridge penetrating the equatorial zone it eventually joined that of the Central Atlantic by about 105 Ma. A single ridge system then extended all the way from off NW Africa to Australia. The southward movement of South America, Antarctica and Australia against the ongoing northward movement of the remainder of Gondwana, separated by this long ridge, became the predominant continental motion.
In the diagram, Africa as a whole is shown fixed. Selected points on the component sub-plates the continent are marked by red crosses. The present-day location of these points in a rigid Africa are indicated by blue circles so that the movement of the local plates is clearer. Large green crosses show that central Africa (Congo) in this model is attached to the fixed reference frame. In reality, Africa as whole (along with its neighbours) was moving steadily NE in this whole time period. Renewed vigour of the Bouvet plume in the interval 130-120 Ma (roughly Hauterivian to start Aptian) is probably responsible for the eastward jump of the main transform offset off SE Africa to east of the Mozambique Ridge.
Last update: 2025 September 18