Reactivation of Magma Pathways: Insights From Field Observations, Geochronology, Geomechanical Tests, and Numerical Models

Field observations and unmanned aerial vehicle surveys from Caldera Taburiente (La Palma, Canary Islands, Spain) show that pre-existing dykes can capture re-direct younger ones to form multiple dyke composites. Chill margins suggest the older were solidified cooled when this occurred. In one example, an 40Ar/39Ar age difference of 200 kyr was determined between co-located dykes. Petrography geomechanical measurements (ultrasonic pulse Brazilian disc tests) a microscopic preferred alignment plagioclase laths sheet-like structures formed by non-randomly distributed vesicles give anisotropic elastic moduli fracture toughness. We hypothesize anisotropy led development margin-parallel joints within dykes, during subsequent volcanic loading. Finite element models also contrast their host rock elevated re-oriented stresses governed propagation. Thus, joints, combined with local concentration rotation stresses, favored deflection magma-filled fractures up 60° At edifice scale, active intrusions could change organization magma plumbing systems cause unexpected propagation paths relative regional stress. reactivation mechanism gives structural memory past stress states, potentially encouraging re-use vents deflecting along rift zones or toward shallow reservoirs.