New interpretation of the spreading evolution of the Knipovich Ridge derived from aeromagnetic data

SUMMARY Insights into the spreading evolution of the Knipovich Ridge and development of the Fram Strait are revealed from a recent aeromagnetic survey. As an ultraslow spreading ridge in an oblique system located between the Svalbard–Barents Sea and the Northeast Greenland rifted margins, the dynamics of the Knipovich Ridge opening has long been debated. Its 90° bend with the Mohns Ridge, rare in plate tectonics, affects the evolution of the Fram Strait and motivates the study of crustal deformation with this distinctive configuration. We identified magnetic isochrons on either side of the present-day Knipovich Ridge. These magnetic observations considerably reduce the mapped extent of the oceanic domain and question the present understanding of the conjugate rifted margins. Our analysis reveals a failed spreading system before a major spreading reorganization of the Fram Strait gateway around magnetic chron C6 (circa 20 Ma).

A Magmatic Seafloor Source at an Ultraslow-Spreading Ridge

An ultraslow-spreading stretch of the Southwest Indian Ridge is thicker than expected: both tectonic and volcanic processes may be feeding the growing seafloor there.