An Integrated Study on the Spatial Distribution and Formation of Contourites

Abstract

This study applies an integrated GIS, outcrop, and physical modelling approach to define and quantify the dominant controls on contourite deposition and distribution. We link observed contourite deposits identified in the Global Contourite Atlas by (Rebesco, et al. 2014) with various spatial oceanographic parameters like: Surface current speed, storm activity, ocean turbidity, tidal amplitudes and geostrophic currents. We find a strong correlation between the spatial distribution of contourites and bottom drag, a parameterization of the friction between the ocean floor and ocean bottom currents (Trossman et al. 2016). Also, ocean turbidity published in Shi and Wang (2010) positively correlates with the distribution of contourites. We find that storm activity plays only a minor role, contradicting previous studies arguing that abyssal storms powered by surface storms strongly influence contourite deposition (Hollister and McCave, 1984). We corroborate this by physically modelling the transfer of wave energy across a modelled thermocline, hypothesizing that the ocean thermocline provides a kinetic barrier for wave energy between the surface and the ocean floor. We integrate these findings with the results of an outcrop study on Miocene contourites in Morocco with the aims of defining the effects of paleogeography on the lateral extent of contourites as well as spatial and temporal variations in sedimentation rate.

AAPG Datapages/Search and Discovery Article #90350 © 2019 AAPG Annual Convention and Exhibition, San Antonio, Texas, May 19-22, 2019