Physical Modelling of the Formation of the Meteor and Islas Orcadas Rises (South Atlantic)

Abstract

The kinematic reorganization of the plate boundaries in the southeastern part of the Antarctic part of the South Atlantic, which expressed in the jump of the spreading axis of the Agulhas Ridge, has led to a restructuring of the structural plan of the region. This process resulted in the formation of the southern segment of the Mid-Atlantic Ridge (MAR), the extinction of the previously active Agulhas spreading ridge, and the formation of the Meteor and Islas Orcadas rises, marking the location of the MAR and located symmetrically about its axis. Based on the research results, the conditions for jumping the spreading axis were identified and an experimental model was constructed for the formation of accompanying structures, in which an important role was played by the accretion of the oceanic crust on the Agulhas Ridge and the westward migration of the Falkland Plateau. This resulted in the southward movement of the southern segment of the MAR, the formation of the Malvinas microplate, and a jump in the axis of the Agulhas spreading ridge, which led to the cessation of spreading on this ridge. An important role in the process of this kinematic restructuring was played by the activity of the Sean hotspot.