Mapping Ocean Gateways from 3D Seismic Data Using Color Processing and Analogues from Seismic Data

Mapping sedimentary features to delineate ancient oceanic gateways from 3D seismic data has long been a challenge owing to their limited vertical resolution. We present the technique of colour processing of seismic data, which improves the vertical resolution to very few seismic samples corresponding to 5–10 m. The result is a representation of the seismic impedance contrast correlation in red–green–blue colours, which creates images similar to satellite images that assist with geological interpretation because the red–green–blue colours can be associated with mud-rich and sand-rich sediments. Using this approach, we have extracted six different sedimentary bedforms from different bottom flow settings and correlated these with the bedform–velocity matrix by Stow et al. (2009) . We then studied bedform assemblies in their regional contexts in the area covered by the 3D seismic dataset. We conclude by comparing a modern analogue and an ancient analogue – both from 3D seismic data – and infer palaeoflow direction and velocity using oceanographic measurements available for the modern analogue. The method provides insights into ocean bottom currents and their impact on the formation of contourite depositional systems in modern and ancient oceanic gateways, which contributes to the reconstruction of the palaeoclimate as an input to present-day climate change models.