New article in Nature Communications
Researchers from the Department of Earth Science of the University of Bergen explain in a paper published in Nature Communications how exhumed mantle domes form at magma-poor continental margins and at ultra-slow mid-oceanic spreading systems controlled by frictional shear zones.
Title: Mantle exhumation at magma-poor rifted margins controlled by frictional shear zones
The transition zone from continental crust to the mature mid-ocean ridge spreading centre of the Iberia-Newfoundland magma-poor rifted margins is mostly composed of exhumed mantle characterized by highs and domes with varying elevation, spacing and shape. The mechanism controlling strain localization and fault migration explaining the geometry of these peridotite ridges is poorly understood. Here we show using forward geodynamic models that multiple out-of-sequence detachments with recurring dip reversal form during magma-poor rifting and mantle exhumation as a consequence of the strength competition between weak frictional-plastic shear zones and the thermally weakened necking domain beneath the exhuming footwall explaining geometry of these peridotite ridges. Model behaviour also shows that fault types and detachments styles vary with spreading rate and fault strength and confirm that these results can be compared to other magma poor passive margins such as along Antarctica-Australia and to ultra-slow mid-ocean spreading systems as the South-West Indian Ridge.