Gravitational sliding on the Mid-Atlantic Ridge at the Kane Transform: Implications for submarine basin-slope degradation and deformation

摘要

Deep-tow side-scan sonar imagery, along with submersible and camera surveys, provides a synoptic view of the sea-floor geology, leading to critical observations and new interpretations for previously unknown gravitational sliding features on the Mid-Atlantic Ridge at the Kane Transform (23°38'N). The sliding on the rift-valley wall occurred mostly as massive slumps of slope-forming gabbroic bed rocks, possibly along mechanically weak, low-angle (30°) detachment faults, creating frontal cuspate ridges and downslope-trending lineaments. The sliding on the transform-valley wall occurred mostly as debris avalanches, producing distributed surficial sediment and bedrock clasts in an apron of hummocky and chaotic terrain on the lower slope, steeply dipping (70°) amphitheaterlike escarpments on the upper slope, and downslope-trending ridges and lineaments on the middle slope.