Das, Himangshu¹, Chris Reed¹, Alan Niedoroda¹
(1) URS Corporation, Tallahassee, FL

ABSTRACT: Time Evolution of Meandering Submarine Channels

The process of meander migration in deep water channels is similar to that in the fluvial channels as both are gradual processes, striving to establish equilibrium of morphological pattern through dynamic interactions between turbidity flow, ambient water and the channel substrate. Although fluvial channel migration processes are well established, interactions between turbidity currents and underlying sedimentation in submarine channels are far less understood and it has mostly been the subject of descriptive studies. Recently acquired 3D seismic images have provided fascinating details of the evolution of some submarine channels and it has been demonstrated that submarine channels evolves through repeated aggradation and lateral migration analogous to fluvial meanders.
The objective of this study is to gain quantitative insight into the paleo flow and sediment condition that might lead to a gradual migration and evolution of those channels. This is achieved through a combination of 2D and 3D models of turbidity current flow and sediment transport. At first, a depth integrated 2D model is used to reconstruct the flow field that allowed us to closely match the migration traces of a deep-water channel from offshore Angola. Later, a fully coupled 3D model is used to demonstrate the formation of scroll bars or lateral accretion packages (LAPs, Abreu et al., in press) as seen in the seismic image of that channel. The numerical simulation of the well resolved Angola channel demonstrates that it is possible to reconstruct the flow and depositional characteristics of submarine meandering channels based on their migration traces.

AAPG Search and Discovery Article #90026©2004 AAPG Annual Meeting, Dallas, Texas, April 18-21, 2004.