Morphometric scaling relationships in submarine channel-lobe systems

Morphometric analysis of submarine fan systems, the largest sedimentary deposits on Earth, demonstrates scaling relationships between genetically related channels and lobe-shaped bodies (LBs) deposited beyond the channel terminus, providing insight into the architectural development of these systems. Compiling dimensional data from depositional systems that cover a range of sediment supply characteristics, tectonic settings, and geographic locations enables investigation into global trends in depositional morphology. LBs have a consistent, scale-independent length-to-width ratio of similar to 2:1. The thickness-to-area ratios for LBs show multiple morphologic trends, likely driven by topographic confinement, with LBs getting proportionally thicker in relation to increasing confinement. Morphometric analysis of genetically related channel dimensions (width, relief, cross-section area) and LB dimensions (length, width, thickness, area, volume) reveals robust scaling relationships; most notably, channel width and cross-sectional area can be used to predict the volume and depositional area of related LBs. These relationships demonstrate that LBs proportionally scale to their concomitant channels, and thus to the volume of sediment supplied prior to an avulsion. While the dimensions of submarine fans scale to associated terrestrial catchments, the building blocks of submarine fans (i.e., channels and LBs) do not, suggesting a down-system decoupling (or lack of scaling) at LB deposition time scales. Applying these morphometric trends and scaling relationships as input parameters for source-to-sink and reservoir models can improve predictions of stratigraphic architecture, sediment partitioning, and sediment/carbon flux in modern and ancient submarine fan systems.