Rates of accommodation and sediment supply are the principal controls on stacking patterns in siliciclastic basin fills. Stratigraphic inversion is aimed at reconstruction of these controls from the detrital record. Efforts to 'explain' siliciclastic basin fills have been focused on analysis and numerical modelling of sequence geometry in response to changes in accommodation, whereas comparatively few studies have attempted to address the role of sediment supply. The compositional and textural properties of siliciclastic basin fills are linked with the evolution of drainage basins through the principle of climatic-physiographic control of sediment production and supply. Application of this principle leads to a method of compositional analysis for distinguishing sequences controlled by high-frequency changes in the rate of accommodation from sequences controlled by high-frequency variations in the rate of sediment supply (order of 10 kyr). This method does not require detailed time control. Changes in rate and type of sediment supplied to depositional systems in response to environmental perturbations in drainage basins are explored in greater detail by means of a numerical model of sediment production under various scenarios of climatic and tectonic forcing. Simulation experiments suggest that drainage basins respond differently to highfrequency tectonic and climatic perturbations. Synthetic time series of cyclically forced sediment production display different types of asymmetric variations in grain size, accumulation rate and residence time of sediments in response to tectonic and climatic forcing. The results also highlight the role of vegetation as the principal modulator of climate forcing, and show that the nonlinear response to climate change may frustrate any attempts at providing broad generalizations of the system's responses. The modelling results confirm the usefulness of a combined analysis of sediment composition and sequence geometry, and the mathematically rich behaviour of the system suggests that further development of this approach is likely to increase our ability to reconstruct forcing mechanisms and initial boundary conditions from the detrital record. of depositional systems in response to secular variations

Physical modelling of clastic sedimentary systems over geological time spans has to resort to analogue modelling since full scaling cannot be achieved within the spatial and temporal restrictions that are imposed by a laboratory set‐up. Such analogue models are suitable for systematic investigation of a sedimentary system's sensitivity to allocyclic changes by isolating governing parameters. Until now, analogue models of landscape evolution were mainly qualitative in nature. In this paper, we present a quantitative approach. The quantitative experimental results are verified and discussed by comparison with high‐resolution data from the Colorado river–shelf system of the Texas shelf that we used as a prototype. The model's dimensions are proportionally scaled to the prototype, except for a vertical exaggeration. Time is scaled using a Basin Response factor to maintain a similar ratio between the period of change and the system's equilibrium time for model and prototype. A Basin Fill factor was used to compare the ratio between the time‐averaged sedimentation rate and the rate of change in accommodation space of model and prototype. The flume‐model results are in the form of sediment budgets that are related to shelf cannibalism and fluvial supply, which are compared with the ancestral Colorado river–delta evolution of the last 40 kyr. Model and prototype have similarities in delta evolution in response to one cycle of sea‐level change. With sea‐level change as the isolated variable, the flume model generates a significant supply pulse caused by headward erosion of the shelf in response to the sea‐level fall. This pulse adds to the yield of the hinterland. The supply induced by sea‐level change persists during the early rise, although its rate declines. A similar trend is observed on the east Texas shelf. We argue that shelfal and fluvial degradation cycles induced by sea‐level changes can significantly influence the timing and amount of sediment supply to basins and must therefore be taken into consideration.

The Quaternary glaciations had a profound impact on the geomorphology and stratigraphy of passive continental margins. The challenge is to resolve the contributions of the main forcing controls relative sea‐level change and sediment flux. The key to answer this question is to understand the interaction between the marine and terrestrial environments, where river dynamics play an essential role. A comprehensible three‐dimensional numerical model is presented in order to investigate quantitatively the behaviour of river–shelf sedimentary systems under glacio‐eustatic conditions. Distinctive features observed in the model results include river avulsion, delta‐lobe switching, incision and knickpoint migration. An important event in the development of the modelled river–shelf system is the establishment of a direct and inextricable link between the drainage basin and the depocentre on the shelf edge, thereby bypassing the exposed shelf. This is termed as ‘drainage connection’. In the model, the timing of drainage connection occurs over a broad interval when the model run is repeated many times with small differences in the initial topography, reflecting the sensitivity of the system to its initial state. It demonstrates the inherent variability in the evolution of a sedimentary system as a consequence of non‐linear behaviour. A statistical approach to modelling is suggested in order to deal with this problem.

The preservation potential of sedimentary deposits is a reflection of the probability that a stratigraphic level will escape reworking. In this paper, the preservation of strata on passive continental margins during glacial-interglacial cycles is investigated by means of a three-dimensional, dynamic numerical model. The reworking of sediment is primarily driven by glacio-eustatic base-level changes, and varies across the shelf. Local topography and the existing drainage pattern influence the distribution of erosion. Statistically the coastal wedge (highstand delta), the adjacent inner shelf and the shelf edge are most vulnerable. The differential preservation, especially of shelf and upper continental slope deposits, is also manifested in the chronostratigraphy, leading to a considerable deviation in the volume distribution from the sediment supply signal. The formation of a subaerial erosional unconformity commences during falling sea level, continues until early rise, and greatly affects paralic deposits. Various scenarios of sea-level change, different gradient contrasts between coastal prism and shelf, and sediment supply and discharge have been investigated.

Changing conditions during Quaternary glacial and interglacial stages have had a great influence on the location and amount of sedimentation, and on the grain size of deposits. In this modelling study, the volume and grain-size distribution in passive continental margin strata are investigated. A principal aspect of the basin-scale grain-size sorting process is the formation of a subaerial erosional unconformity. During forced regression, deltaic coarsening-up sequences are deposited on the shelf. The relatively coarse-grained topsets of these successions have a lower preservation potential than the finer prodelta deposits. Therefore, erosion on the exposed shelf results in enrichment of river-transported sediments with coarse material during sea-level lowstand. Thus, shelfal strata are depleted of coarse material, increasing the coarse content of deposits on the upper continental slope. In contrast, in the absence of an erosional unconformity, the composition of sediments on the shelf is relatively coarse. The extent to which sediment within a stratigraphic column has been separated into coarse strata, as opposed to mixed compositions, is expressed as a 'differentiation ratio'. Interconnectedness of coarse-grained sediment bodies in the stratigraphy of the continental shelf and slope is closely related to the palaeogeographical evolution, and is consequently a highly variable property.