Agulhas Plateau and Mozambique Ridge: Two LIPS and their effect on oceanic circulation


Contact
Gabriele.Uenzelmann-Neben [ at ] awi.de

Abstract

The seaway south of South Africa represents a critical gateway within the global circulation. Here, warm surface and cold deep and bottom water masses meet and lead to a transfer of heat and salt between the Indian and Atlantic Oceans. This transfer maintains the global thermohaline circulation. The paths of the oceanic currents are strongly influenced by the seafloor topography observed in this region. Thus, the tectonic evolution of the South African continental margin and the gateway starting in Cretaceous times are of major importance in order to understand the evolution of the current system and the transition from the Greenhouse to the Icehouse world.The sheared continental margin of southern South Africa is characterized by a pre-break-up basin filled with meta-sediments and the Diaz marginal ridge. Alternating layers of volcanic flows and sediments can be observed in the Agulhas Passage immediately south indicating a possible reactivation of parts of the Agulhas-Falkland Fracture Zone. The Agulhas Ridge, part of the Agulhas-Falkland Fracture Zone further west in the southern Atlantic, acts as a barrier to the flow Circumpolar Deep Water from the south to the north and deflects the water mass to the west and east. Even though this structure originates in the early break-up of Gondwana it still rises to water depths of only 2000 m, which further indicates a later reactivation of parts of the fracture zone. The gateway itself is characterized by the Agulhas Plateau, which has been postulated to originate in the interaction of the Bouvet Hotspot and a triple junction and thus to fall within the world-wide suite of Large Igneous Provinces. A similar structure has been identified for the crust of the southern Mozambique Ridge. This rises the question whether those two LIP events were related, happened at the same time and how they tie in with other LIP events observed in Late Cretaceous times such as the formation or the Kerguelen LIP. Furthermore, we may speculate on the effect those magmatic events had on the evolution of both oceanic currents and the climate.



Item Type
Conference (Invited talk)
Authors
Divisions
Programs
Peer revision
Not peer-reviewed
Publication Status
Published
Event Details
Seminar, Instut de Physique du Globe, Universitaet Strassburg, Frankreich..
Eprint ID
18680
Cite as
Uenzelmann-Neben, G. (2008): Agulhas Plateau and Mozambique Ridge: Two LIPS and their effect on oceanic circulation , Seminar, Instut de Physique du Globe, Universitaet Strassburg, Frankreich. .


Share

Research Platforms
N/A

Campaigns


Actions
Edit Item Edit Item