Extensive outcrops of coarse-grained channel to fine-grained levee deposits of the Campanian Cerro Torro Formation are present throughout the Torres del Paine National Park in southern chile ( Figure 1 ; Fildani et al, chapter 33, this volume). The outcrop panel in Figure 2 represents part of one face of a nearly continuous exposure mapped in this paper that is present on all four faces of a mesa within the Silla Ojo Syncline ( Figure 1 ). The depositional architectures consist predominantly of sheetlike, tabular elements comprising interbedded sandstone and shale bedsets, onlapping older levee deposits (described by Barton et al., chapter 39, this volume). Isolated channel elements and scour features are also present. The vertically stacked, tabular architectural elements observed in the outcrop panel are interpreted to represent a phase of partially confined to unconfined deposition outboard of a major levee avulsion site, analogous in many respects to the avulsion deposits described by Hiscott et al. (1979). Overlying and truncating the tabular elements of the avulsion deposits is a thick, multistory channelized conglomerate ( Figure 2 ) with internally organized and chaotic bedding and impressive debris flow deposits. A similar vertical facies transition from levee to avulsion to channel deposists is also described by O’Byrne et al. (chapter 30, this volume) and Arnott (chapter 29, this volume) from the Isaac Formation, Canada.

Abstract A hierarchical organization of heterogeneity in sedimentary systems has long been noted and this concept was explicitly built into Shell’s proprietary reservoir modeling system in the early 1990’s. The approach nested progressively finer levels of detail within parent objects and provided a mixed deterministic and stochastic technique for achieving realistic reservoir architectures at multiple levels in the hierarchy of heterogeneity. By 1999, the concept of hierarchical static modelling had been extended to basin-scale, as a means to promote consistency between local and regional data, interpretations, and models. Tangible business benefits were demonstrated for both exploration and appraisal decision making and the approach promoted continuity in subsurface evaluation along the whole exploration through to production lifecycle. Key to the success of the multiscale static modeling approach is the combination of multiple data types (having differing resolutions and degrees of completeness) and global geological knowledge to complete the gaps associated with data resolution limits and incomplete data coverage. Synthetic seismic expression of resultant models is used to ensure consistency with available seismic information.

Abstract Two end-member classes of sediment distribution systems on topographically complex slopes are distinguished here: (a) cascades of silled sub-basins , and (b) connected tortuous corridors . In the first scenario a process of filling and spilling of successive silled sub-basins down a slope occurs. For each sub-basin a sill tends to hinder further downslope flow of at least the basal sandy portions of sediment gravity flows until deposition reduces the relief sufficiently to allow spill down-slope. Spill is associated with incision in the sill. In the connected tortuous corridors scenario, flows avoid bathymetric obstacles, but follow a (laterally confined) continuous tortuous path down the slope. Without complete three-dimensional imaging of slope architecture it can be possible to incorrectly infer from two-dimensional profiles a cascade of silled sub-basins model. Thus flow paths in adjacent apparent subbasins can be connected out of the plane of section. Convergent thinning and convergent baselap stratal patterns occur in both scenarios, but only in the silled sub-basin case do such patterns occur against closing frontal slopes. For a given complex slope morphology, dominant controls on fill patterns and reservoir architecture are (a) the history of sediment supply character, and (b) rates of structure growth relative to rates of smoothing of topography by erosional and depositional processes. Two particularly important aspects of sediment supply are (i) flow volumes relative to scales of receiving spaces, and (ii) flow properties (in particular, transported grain size distribution, flow thickness and flow concentration), these controlling depositional gradients and the equilibrium profiles to which slopes tend to grade.

Abstract The latest Ordovician and lower Silurian fill of the Welsh Basin contains a range (in terms of scale, sediment texture, stratigraphic architecture and supply configuration) of deep-water depositional systems that record the influence of basin-floor topography on sediment distribution patterns. Systems supplied from the eastern basin margin at a time of broadly rising relative sea-level are interpreted to have initially filled an inboard base of slope depression lying above a tilted basement fault block (Cerig Gwynion Grits System). An opposing slope is thought to have caused deflection of turbidity currents to run parallel with the strike of the slope. Following this fill phase, a channel-fed lobe system (Caban-Ystrad Meurig System) extended further basinwards. After flooding of the eastern basin margin, voluminous, texturally immature axial systems, supplied from the southern basin margin, developed. These systems exhibit evidence for deflection of flows to run parallel to tectonically induced slopes and probable local flow reflections in areas of obliquity between bounding slopes and incident flows. The architecture of the lateral-slope to basin-axis profile has been plausibly modelled using a geometric forward model with a low-gradient lower basin slope and basinward higher aggradation rates and sand percentage.

Abstract Onlap terminations of deep-marine sandstones in the Grès d'Annot, SE France, exhibit a range of styles, from abrupt onlap to feathering ‘aggradational onlap’ geometries. These are well exhibited in the large exposure of southward onlap terminations at Montagne de Chalufy, on the southern end of the Trois Evêchés Massif (Alpes de Haute Provence). These stratal architectures are here simulated by geometrical models that are governed simply by bounding slope gradients and the ratio of coeval slope to basinal aggradation rates. In cases of no coeval deposition on bounding slopes, pure onlap results. In cases of high slope aggradation rates relative to basinal aggradation rates, a feathered geometry results with successive sandstone beds onlapping against successively younger slope drapes. The cyclicity of alternating sand-rich and sand-poor packets seen at Chalufy results in a stepped climbing trajectory of successive slope base positions, with climb angle equal to bounding slope angle when mud-poor sandy flows deposited sandstone bodies with abrupt onlap, and climbing more steeply when slope drapes are deposited. An implication of this result is that any zones of facies change and palaeocurrent swing that are related to distance from bounding slope will exhibit a comparable vertical trajectory through time. The two end member termination types can be compared with the convergent-baselapping and convergent-thinning seismic facies used in the Gulf of Mexico subsurface and elsewhere. The convergent-baselapping seismic facies may include both abrupt onlap and intervals of feathering aggradational onlap if the presence of slope drapes is not resolvable by the frequency content of the available seismic data.