Slab pull and ridge push can cause rifting when two ends of a continent is subjected to these forces. If the continent contains a weak zone, these forces can be sufficient to cause continental break-up. Subduction may also cause rifting when the lithosphere bends prior to subduction.

When did rifting occur?

Rifting began at about 800 Ma but did not lead to separation of the continents until about 700 Ma (Fig. 10A). The early phases of rifting were epicontinental and are expressed as rift sequences in the Adelaide Rift and other graben structures.

Why does continental rifting occur?

Where tectonic plates move away from one another the lithosphere thins. The underlying asthenosphere rises and expands like a hot-air balloon, elevating a broad region. If the plate is capped by thick continental crust, the resulting continental rift zone rises high above sea level.