Geomorphic Channel Patterns of Deltas versus Distal Submarine Fans: Implications for Sedimentation Processes on Earth and Mars

Channel systems at the distal limits of submarine fans show variability in channel size and bifurcation patterns. This information is useful in constraining channel properties in static reservoir models, e.g. the mean and range of values typical for channel dimensions, sinuosity, and branching angles. Criteria were evaluated that might help discriminate between deltas and submarine fans based on the bifurcation pattern of the channels present on the fans, i.e. by using the properties of channel width, length, sinuosity, branching angle and gradients. Submarine fans and deltas show nonlinear decreases in mean channel width and channel length with increasing bifurcation order. Sinuosity is also found to decrease down fan. Channel branching angles appear to be stochastic and do not provide a meaningful measure to discriminate between fan types. The trends of mean channel length versus mean channel width follow a power law. The steepness of the power law trend does not appear to correlate with the dominant grain size present on the fan, the water depth of the fan, margin type or drainage basin size. The exponents of the power law fit for deltas are somewhat smaller than the exponents for submarine fans, but taking into account the uncertainties on the values, the two types of fans cannot be wholly distinguished. We also characterized the channel patterns on a Martian submarine fan and delta and compared them to terrestrial fans. Channel lengths fall off slightly more slowly for a