The Athabasca lower delta plain and subaqueous delta plain (lower Athabasca Delta) are mainly a product of fluvial influence and a shallow receiving basin. The geomorphology of the lower Athabasca Delta reflects these conditions, and is characterized by bifurcating, low-sinuosity distributary channels, muddy interdistributary basins, distributary mouth bars and a gently sloping offshore profile.

The major sandy bodies within the lower Athabasca Delta are the product of deposition within the distributary mouth bar, the crevasse-splay and the infilling distributary channel.

Channel infilling occurs due to vertical aggradation as well as through the process of limited lateral accretion. Vertical aggradation is due to bedform migration along the channel thalweg, and produces a uniform sand sequence. Limited lateral accretion involves the process of step-wise bar formation, and occurs diagonally as opposed to strictly vertically or laterally.

The type of channel-fill sequence is a reflection of the rate of channel abandonment.