Geology

Sedimentary basins along the Mozambique margin formed during extension and breakup of eastern Gondwanaland. Intra-continental rift basins of late Carboniferous to Triassic age (Karoo) and an early to mid Jurassic marginal rift system underlie a thick sedimentary wedge deposited during the separation of Mozambique from eastern Antarctica and Madagascar from the mid Jurassic. Three main, approximately north-south trending, transfer zones separate the margin into four basin systems.

Rovuma Basin
An extensional rift formed along the Davie Fracture Zone during opening of the West Somali Basin from the early Jurassic is overlain by Rovuma Delta deposits (from the late Cretaceous), with Miocene slope failure and slump forming deep-water thrust belts. Late extension related to the offshore East African Rift system (Kerimbas Graben). Total sediment thickness reaches 10 km over the Rovuma Delta and approximately 5 to 8 km in the southern Rovuma Basin.
Angoche Sub-Basin
A relatively simple passive margin segment over extended continental to oceanic crust with a thick (up to 7 km) Upper Jurassic to Tertiary sediment wedge over a Lower to Middle Jurassic syn-rift including local salt. Likely subduction below the Davie Ridge on the east flank. Basin is undrilled.
Zambezi Delta and the Beira High
A major depocentre over a Callovian aged near-shore failed rift system, the Zambezi Delta Depression, with 12 to 14 km of total sediment cover, with a large crustal block, the Beira High, to the south-east with 6 km to 3 km of sediment over the crest. Limited drilling restricted to Tertiary plays on the delta.
Limpopo Basin (Mozambique Plain)
Located west of the Mozambique Fault Zone / Mozambique Ridge. Upper Jurassic to Tertiary section (4 – 6 km) over highly extended continental to oceanic crust, floored by thick Lower Jurassic volcanics. The Mozambique Plain province is cut by several NNW-SSE to N-S trending Jurassic, Lower and Upper Cretaceous and Tertiary rift basins in the west; the Palmeira, Changani and Mazenga grabens and the mainly offshore Xai-Xai Graben. The major onshore fields are located on the Pande-Temane High, located between the Mazenga Graben and the Save Sub-basin and south of the Mazenga Plateau (a basement uplift). The north-south trending Save Sub-basin runs along the eastern coast and adjacent offshore west of the Barra Falsa High.