Global Variation in Submarine Channel Sinuosity: Implications for Channels in Space and Time

Jeffrey Peakall, Ransome Corney, Gareth Keevil, Ian Kane, and Bill McCaffrey
University of Leeds, Leeds, United Kingdom

Submarine channels can exhibit spectacularly sinuous planforms and these have drawn comparison with meandering fluvial channels. Deep-marine channel systems can however also form remarkably straight channels with sinuosities barely above one. The range of sinuosity observed in submarine channels can be expected to lead to first order variations in the intra-channel facies architecture of the systems, most notably in terms of deposition on the inside of channel bends. As a consequence, understanding the controls on sinuosity is important for predicting large-scale facies distributions within these systems.

Submarine channels have been shown to individually exhibit a gradual increase in sinuosity towards the mid-fan, a maximum sinuosity at approximately the mid-fan, and then a gradual decline towards the termination of the system. Analysis of the peak sinuosities versus the longitudinal slope of the systems has shown a general trend between maximum sinuosity and slope with the most sinuous being on low slopes and the least sinuous on high slopes. This led to a classification of fans in terms of two end-members, low sinuosity – high gradient systems, and high-sinuosity – low gradient systems.

Here we look at channel sinuosity as a function of latitude and demonstrate that the strength of the correlation between the two is strong. Importantly, the dependence of sinuosity on latitude is very much stronger than the dependence on slope. The possible underlying reasons for this observation are then explored.