Variability of Sea?Surface Magnetic Anomalies at Ultraslow Spreading Centers: Consequence of Detachment Faulting and Contrasted Magmatism?

The capacity of oceanic crust to record geomagnetic polarity reversals makes sea-surface magnetic anomalies an essential tool study plate tectonics. are usually well-defined at magmatic spreading centers, but distorted and eventually disappear on magma-poor mid-ocean ridges such as the ultraslow Southwest Indian Ridge (SWIR), making their interpretation difficult. We attribute variability SWIR alternance detachment faulting. A three-layer model is used simulate influence anomalies. Conversely, observed profiles modeled unravel off-axis crustal structure past mode spreading. intruding gabbro bodies footwall faults play a major role in explaining slow ridges.