Deformation in an accretionary melange, Alexander Island, Antarctica

Alexander Island contains several belts of melange in a wide accretionary complex. One melange belt in the northwest of the island incorporates both oceanic and trench-fill material. It evolved by many different deformation mechanisms: dispersed independent particulate flow (IPF) and limited cataclasis at shallow levels; and diffusion mass transfer (DMT) and limited crystal plastic processes at deeper levels. Fluid pressures may have risen due to the subduction of young hot oceanic crust, which probably affected the structural evolution of the region by controlling the strength of the decollement and hence the taper of the accretionary prism.