The role of lithospheric processes on the development of linear volcanic ridges in the Azores

摘要: Abstract Linear volcanic ridges (LVRs) are widespread along the Azores plateau and often used as a tectonic marker of surface stress field. Nevertheless, mechanisms that drive emplacement development these structures not well established they have been attributed to diffuse deformation, off-rift extension or result interaction between hotspot brittle lithosphere. This study hypothesizes linear magma into pre-existing damaged lithosphere, using 3D finite-element representation lithosphere underlying ductile mantle, assuming deformation is driven by plate boundary forces applied at edges, describe global kinematic models. The layer described an elastoplastic rheology with progressive damage, where fractures assumed be analogous localized shear bands. mantle underneath modeled viscoelastic exerts drag base layer. modeling shows lithospheric processes alone can justify spatial distribution ridges, even Faial Ridge. factors controlling fracturing pattern geometry velocity conditions, shearing introduced East Fracture Zone/Gloria fault limit viscous spatially varying thickness. Along Terceira Rift predicted match orientation LVRs in second (~ N135°–N140°) third (N150° N–S) sectors provide explanation for arcuate shape rift itself. thickness variations crucial more recent LVRs, which occur In best fit model top viscosity 1 × 1022 Pa s 5–15 km depth, present-day fracture network takes ~ 3 Ma develop.