The influence of creeping slope failure on turbidity current behaviour

Abstract

Erosional scars, slumps, slides and debrites (mass-transport deposits) on submarine slopes form relief that influences turbidity current behaviour. However, the interaction of mass-transport deposit emplacement kinematics (i.e. rapid emplacement versus creep), the morphology of the evolving seafloor topography, and subsequent flow types is complicated. This study describes two outcrop examples of deep-water, predominantly turbiditic, deposits overlying mass-transport deposits, from the Eocene slope succession of the Aínsa Basin (Spanish Pyrenees). In both examples, the masstransport deposit substrate continued to creep contemporaneously with turbidity current deposition and bypass. In the first case study, structures in the mass-transport deposits are extensional and oriented parallel to flow. In the second, structures are compressional and oriented perpendicular to flow. Mudstones dominate the slope succession, but deposits overlying mass-transport deposits form sandstone-prone accumulations. Lateral confinement by flow-parallel extensional faults enhanced channel-formation. Channel incision occurred close to the exhumed fault plane on the hangingwall.Incision ceased as the fault gradually locked-up, and channels avulsed to the hangingwall of a newly This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process which may lead to differences between this version and the Version of Record. Please cite this article as