Significance of first-order faults in folding mechanically isotropic layers: Evidence from the Sudbury Basin, Canada

摘要: Abstract The Sudbury Basin is a non-cylindrical fold basin demarcated by the layered Igneous Complex (SIC), eastern part of which transected prominent curved faults. Folding SIC and adjacent rock units occurred in brittle field peculiar due to its petrographically distinct, but initially mechanically similar layers. Overall, layers are characterized low levels solid-state strain raising question how layer contacts acquired their curvature. We addressed this developing G.I.S.-based workflow analyze orientation slip vectors Slip form clusters normal reverse along given fault. clustering best interpreted terms successive events during folding SIC. As faults formed most likely as planar prior they subsequently served anisotropic elements results contribute (1) better understand mechanisms thick melt sheets upper crust, (2) explain apparently incompatible principal axes progressive deformation, (3) efficiently kinematics fault zones close Earth's surface.