RELIEF AND CONTEMPORARY STRUCTURE OF THE SOUTHERN MID-ATLANTIC RIDGE

The considered part of the Mid-Atlantic Ridge extends from the Agulhas-Falkland fracture zone to the Bouvet triple junction. This segment has a contrasting topography. In its southern part, it has the morphology of an axial rise, while in its middle part it has the morphology typical for a slow-spreading rift valley. In the northern part, an area with transitional morphology can be distinguished. Three morphostructural complexes of transverse faults are distinguished, approximately corresponding to areas with various morphology. Such a different structure and segmentation of the spreading ridge became possible owing to the thermal influence of the Shona and Bouvet mantle plumes in the southern part of the considered segment and the Discovery mantle plume in its northern part. To reconstruct the morphostructure formation conditions in the ridge axial zone, physical modeling was implemented. In our experiments, we obtained various relief types and transverse discontinuities complexes depending on the distance from the thermal anomaly. They match the natural morphostructures. The modeling results suppose that the main formation conditions of the contemporary Mid-Atlantic Ridge terrain are spreading obliquity, thermal anomaly intensity, and the plume center position relatively to the spreading axis.