Net deposition is accompanied by systematic loss of sediment mass from the transport system. How is this mass loss reflected in the deposits, and to what extent can it be used to predict streamwise facies changes? We review mass-extraction analyses of laboratory experiments on fluvial channel stacking; experimental and field turbidites that show a change from channel-dominated to lobe-dominated deposits at about 80% total mass extraction; and experimental, theoretical, and field studies that show a close connection between rate of mass loss and rate of downstream grain-size fining. Applied thoughtfully, depositional mass balance provides a framework for quantitative prediction and comparison across basins of varying scale and shape.

Physical experiments in laboratory tanks allow observation of basin-scale processes under controlled conditions and greatly accelerated time scales. But to what extent are the observations relevant to the field? Judge for yourself as we review the results of recent experiments on steering of channels by tectonic tilting, interaction of axial and transverse river systems, and wave and tide effects on deltas. We'll also look at natural similarity and its role in explaining the “unreasonable effectiveness” of stratigraphic experiments.