Morphometric Scaling Relationships in Submarine Channel-Lobe Systems: Implications for Turbidite Depositional Processes and Stratigraphic Architecture

Abstract

Submarine fans represent the largest sedimentary accumulations on Earth and their constituent channels and channel-mouth deposits (CMDs; i.e., ‘lobe deposits’) form significant petroleum reservoirs. A dataset of compiled and interpreted channel and CMD morphometrics from 35 submarine fan systems demonstrates scaling relationships between genetically related channels and CMDs, providing insight into the architectural development of these systems. Including data from submarine fan systems that cover a range of sediment supply characteristics, tectonic settings, and geographic locations enables investigation into global trends in depositional morphology. CMDs have a consistent, scale-independent length-to-width ratio of ~2:1. The thickness-to-area ratios for CMDs show two morphologic trends: CMDs that are (1) proportionally thicker and (2) proportionally thinner in relation to their depositional area. We interpret that these trends are driven by topographic confinement during deposition. Morphometric analysis of genetically related channel (width, depth, cross-sectional area) and CMD 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 CMDs. These relationships demonstrate that CMDs proportionally scale to their concomitant channels and thus to the volume of sediment supplied prior to an avulsion, providing insights into depositional processes of submarine fans. However, channel and CMD dimensions do not or only weakly scale with associated catchment parameters (catchment area, fluvial sediment discharge, water discharge). Applications of these results include predicting stratigraphic architecture, sediment partitioning, and sediment/carbon flux in modern and ancient submarine channel-lobe systems.

AAPG Datapages/Search and Discovery Article #90323 ©2018 AAPG Annual Convention and Exhibition, Salt Lake City, Utah, May 20-23, 2018