Magmatic activities on the Southwest Indian Ridge between 35°E and 40°E, the closest segment to the Marion hotspot

摘要: [1] We conducted geophysical surveys, including bathymetry, gravity, and magnetism, within a first-order segment of the Southwest Indian Ridge (SWIR) between Prince Edward Eric Simpson fracture zones (FZs) (latitude 35°–40°E, PE), in vicinity Marion hotspot. Segment PE includes four orthogonally spreading second-order segments (PE-1, PE-2, PE-3, PE-4) long, oblique axial valley (NTD-1). Segments PE-1, PE-4 are magmatic, whereas PE-3 NTD-1 characterized by low magmatic activity. is nascent contains three tiny sections. Each low-magmatic interval along axis lies two segments. This segmentation pattern similar to SWIR Gallieni Melville FZs; therefore, strong melt-focusing process can be expected. Different characteristics suggest that activity each varies among other as well SWIR. Continuous seafloor morphology isochrons over off-axis areas PE-1 shortened after C2An chron. The V-shaped bathymetric structure suggests melt supply center has migrated westward. westward migration would have reduced at C2An. obliquity may also Geophysical mainly controlled comparatively contribution from