AN EXPERIMENTAL MODEL OF THE ARCHITECTURAL DEVELOPMENT OF SUBMARINE FAN CHANNELS DUE TO DEPOSITIONAL TURBIDITY CURRENTS

Predictive sedimentation models for submarine channel systems depend upon an understanding of the complex interaction between a turbidity current and the channel it constructs, and upon the subsequent stratigraphy. Submarine channel models based upon seismic-stratigraphic studies not only suffer limitations due to the lack of supporting sedimentological data, but also by limited spatial and temporal resolution. Presently, there is no method available to observe or collect meaningful data of the process of a turbidity current traversing and depositing sediment along a submarine fan channel, thus an experimental approach is undertaken. We conduct scaled laboratory experiments to investigate the interaction of a sediment-laden, depositional turbidity current with a sinuous channel. Morphological and architectural development of the channel, and channel complex deposits, are examined in space and time. Continuous channel overspill, flow stripping downstream of bend corners, construction of perched channel-levee deposits, and reach dependent alternating coarse/fine grained channel and levee deposits are observed. Channel geometry and relative current thickness strongly controls down-channel, and cross-channel depositional patterns, deposit thickness, grain-size sorting and levee development.