Abstract Debris flows tend to conserve their density, whereas turbidity currents constantly change theirs through erosion, deposition, and entrainment. Numerical models illustrate how this distinction leads to fundamental differences in the behaviors of debris flows and turbidity currents and the deposits they produce. The models predict that when begun on a slope that extends onto a basin floor, a debris flow will form a deposit that begins near its point of origin and gradually thickens basinward, ending abruptly at its head. By contrast, deposition from an ignitive turbidity current (i.e., one that causes significant erosion) will largely be restricted to the basin floor and will be separated from its origin on the slope by a zone of erosion. Furthermore, the turbidite will be thickest just beyond the slope base and thin basinward. These contrasting styles of deposition are accentuated when debris flows and turbidites are stacked.