Impact of Discharge, Sediment Flux and Sea‐Level Change on Stratigraphic Architecture of River–Delta–Shelf Systems

Abstract

Variation in sediment transport and temporary sediment storage at large spatial and temporal scales is governed by inherited relief and by the interaction between climate change (water discharge and sediment yield), eustatic sea-level change and tectonics. These processes influence the character of sedimentary successions, and are difficult to reconstruct from stratigraphy alone. Physical modelling can help by allowing observation and quantification of processes that generate model stratigraphy. Sediment transport in the model set-up shows diffusive behaviour. Non-dimensionalizing the relevant physical parameters that underlie model stratigraphy allows a comparison with real-world examples. The effect of (changes in) the forcing parameters (discharge, sediment yield, sea-level change and consequent shoreline position) on a loose bed of sand in a set of experiments is measured by means of high-resolution digital elevation models (DEMs). These DEMs are transformed into geological maps, profiles and Wheeler diagrams that allow detailed reconstruction of sediment flux and routing, storage time, and headward erosion rates. All raw data are stored in the Pangaea database, and are publicly available. A synthesis of all experiment results obtained over the past 10 years has resulted in a first-order prediction of sediment flux that is induced solely by sealevel change. The flux changes with relaxation time (response time) of the system, transport efficiency of the river system (in terms of slope gradient), and the amount that sea level drops below the shelf edge (change in slope gradient); all variables are dimensionless. The results are presented as templates covering systematic trends in the effects of the dimensionless parameters on stratigraphic architecture, which allows for the assessment of the impact of sea-level change on sediment flux relative to the other forcing parameters.

Inferring autogenically induced depositional discontinuities from observations on experimental deltaic shoreline trajectories

“…Increasing water discharge decreases the river gradient, causing erosion in the river, therewith increasing sediment supply S to the delta; decreasing water discharge increases the river gradient, causing deposition in the river, and decreasing the regional sediment supply S to the delta. As a result, regional sediment supply to the delta is approximately proportional to water discharge S ∝ Q (van den Berg van Saparoea and Postma, ; Postma and van den Berg van Saparoea, ). This causes the regional sediment supply to the delta to fluctuate in‐phase S IP ∝ E and out‐of‐phase S OP ∝ − E with sea level respectively (Leeder et al ., ; Perlmutter and Plotnick, ).…”

“…This procedure is hindered by the complexity of the functional relations between independent and dependent variables. Many of these relations have been addressed by a great number of researchers: modelling of deposystems (Paola et al ., ); experimental scaling (Schumm et al ., ; Paola et al ., , ; Peakall et al ., ; Paola, ; van Heijst and Postma, ; Castelltort and van den Driessche, ; Postma et al ., ; Kleinhans et al ., ); autogenic mechanisms (Tipper, ; Muto and Swenson, ; Kim and Paola, ; Muto et al ., ; Nicholas and Quine, ; van Dijk et al ., ; Karamitopoulos et al ., ; Leva López et al ., ); allogenic controls on shoreline (Pitman, ; Muto and Steel, ; Kim et al ., ); autogenic controls on shoreline (Muto and Steel, , ; Kim et al ., ; Kleinhans et al ., ); discharge control on supply (Leeder et al ., ; van der Zwan, ; van den Berg van Saparoea and Postma, ; Postma and van den Berg van Saparoea, ); discharge and supply control on stratigraphy (Postma and van den Berg van Saparoea, ; Carvajal et al ., ); supply control on accumulation (Tipper, , , , ; Kemp, ; Kemp and Sexton, ); accumulation (Sadler, , , ; Sadler and Strauss, ; Kemp and Sexton, ); multivariate control (Heller et al ., ; Kim et al ., ; Burgess et al ., ; Postma and van den Berg van Saparoea, ; Burgess and Prince, ); prediction vs. inference (Paola, ); supply vs. sea level (Muto and Steel, ; Burgess and Hovius, ; Perlmutter et al ., ; Carvajal et al ., ; Bijkerk et al ., ); and sea‐level curve vs. shoreline trajectory (Pitman, ; Martin et al ., ).…”

Estrategias cuantitativas para el estudio de cerámica arqueológica. Una propuesta desde el caso de la cerámica histórica alavesa

“…Como un conjunto equivalente aunque mediatizado por procesos de equifinalidad, que pueden suponer el mismo resultado a partir de estados iniciales diferentes (LYMAN, 2004;ESCRIBANO-RUIZ, 2011: 110). A large number of factors, many of which are linked, may contribute to the stratigraphic product, and likely more than anywhere else the notion 'equifinality' is applicable to stratigraphic successions (POSTMA, VAN DEN BERG, 2008). …”