David Amblas, Scott Polar Research Institute, University of Cambridge, UK
Thomas P. Gerber, Statoil Research and Technology, Norway
Steven Y.J. Lai, National Cheng Kung University, Taiwan
Miquel Canals, CRG Marine Geosciences, University of Barcelona, Spain
Julian A. Dowdeswell, Scott Polar Research Institute, University of Cambridge, UK
Towards an understanding of the long-term evolution of submarine canyons
The morphology of Earth’s continental slopes is in many ways similar to that observed in terrestrial uplands. Where the seafloor descends from coastal to abyssal depths it is sculpted by submarine canyons that in both form and scale are comparable to river valleys in erosional landscapes. Yet the continental slope is also a site of long-term sediment accumulation and, as such, contains a record of its surface evolution beneath the present-day seafloor. Though it can be helpful to draw on surface process models developed for upland landscapes to explain the evolution of continental slopes, a deeper understanding of canyon development requires models for the submarine processes that build and shape the slope.
In this contribution we summarize a number of recent studies that together have shed new light on canyon form and growth. We document observations and measurements from the Catalano-Balearic Basin (NW Mediterranean) that relate the long-profile form of canyons and channels to the processes that control their evolution. We briefly present a model for the long-profile curvature of submarine canyons that includes the combined effects of turbidity currents and background (i.e. hemipelagic) sedimentation, and compare the range of model profile shapes with those observed on the present-day NW Mediterranean slope. Finally, we report on a new line of experimental research aimed at producing canyon morphologies at reduced-scale (Figure). We show that by isolating two key processes – the progressive growth of slope relief and a constant source of unconfined gravity flows – we are able to produce a canyon growth sequence and morphologies that appear similar to what’s observed at field scale. We conclude our discussion with some remarks on our view of the outstanding problems and critical research questions related to canyon geomorphology and stratigraphy that will motivate future lines of research.
Theme 1: Canyon processes in the space-time continuum (formation, evolution, circulation)
Submarine canyons formation and evolution, sedimentary processes, long-profile analysis, experimental modeling