Abstract Tidally influenced meandering river deposits of the Cretaceous middle McMurray Formation are characterized by rapid vertical and lateral lithological and associated reservoir property changes. Within the reservoir, water may occur below, above, and in the middle of the bitumen column, and there may be multiple gas intervals. Although conceptual understanding about the depositional environment and its control on distribution of different fluids (bitumen, water, and gas) is documented in literature, integration of these concepts into reservoir models and history matching through flow simulation is lacking. Thus, even in areas with closely spaced wells (as much as several hundred meters apart), geostatistical modeling approaches show high degrees of randomness. This chapter closes the gap between the conceptual mapping and numerical modeling approaches. Specifically, the workflow for creating a deterministic three-dimensional (3-D), object-based (geobody) model, which integrates data from closely spaced wells, high-quality 3-D seismic data, and sound geologic concepts is shown. The geobodies are typically large-scale depositional elements comprising meandering river deposits. Geobodies include channel lag breccia (tens to hundreds of meters wide and as much as several meters thick), lower and upper point-bar deposits (from several hundreds of meters to as much as 5 km [3 mi] wide and as much as 40m [131 ft] thick), and mud plug deposits (as much as 500m [1640 ft] wide and as much as 40m [131 ft] thick). Because of the potential impact on reservoir development economics, top water, top gas, and low-bitumen, high-water saturated zones are mapped as distinct geobodies. Based on their reservoir development potential, geobodies can then be classified as reservoir flow unit types 1 and 2, reservoir flow barriers, and reservoir flow impairments.

Abstract Previously termed concave bank-bench deposits, point-bar-tail deposits, and distal point-bar deposits, counter-point-bar deposits have received little research attention, and their stratigraphy and sedimentology is poorly understood in modern and ancient river meander belts. The stratigraphy and lateral continuity of counter-point-bar deposits were studied in the modern Peace River Delta, northeast Alberta, Canada. Morphology of counter-point-bar deposits was identified as having concave-shaped scroll-bar and vegetation patterns, and they are always located immediately downriver from sandy point bars. Stratigraphy of counter-point-bar deposits, composed of 55 to 86% silt, were studied using a vibracorer to depths of 6.5 m and channel-bottom grab samples to depths of 20 m over a river distance of 1800 m. This contrasts with 95 to 100% sand in adjacent point-bar deposits. Like point bars, counter point bars are also lateral-accretion deposits, but are composed of inclined heterolithic strata. Counter-point-bar deposits can form in short-radius meanders, as well as in wide-radius broad meanders. Counter-point-bar deposits formed where channels impinge at low angles (10 to 40°) against bedrock valley sides or other erosion resistant sediment. Within the Athabasca River Delta, a different feature called an eddy-accretion deposit, was studied and compared to counter-point-bar deposits. Eddy-accretion deposits formed as short-radius, pronounced concave scroll-bar and vegetation patterns that notably arc up-valley. In contrast to the counter-point-bar deposits analyzed, these deposits are thicker, sandier, and not as laterally extensive for a channel of a given size. Eddy-accretion deposits formed where river flow impinges more directly against (40°–140°) a valley side or channel margin composed of bedrock or resistant sediment such as an oxbow-lake fill, abandoned-channel fill or, as in this case, a Holocene prodelta deposit. The eddy-accretion deposit studied is up to 500 m wide and 24 m thick, although probably closer to 34 m thick during near-bankfull discharge. It is composed of up to 80% sand.

Abstract In many ways, incised valleys reflect in a condensed form the complexity of the entire stratigraphic record. This is because the formation and filling of geographically and stratigraphically isolated incised valleys is dependent on the interplay of the same set of variables that is responsible for the stratigraphic record of most alluvial, coastal, and shallow-marine deposits. Thus, valleys and their fill provide a miniature “laboratory” in which to examine how autocyclic and allocyclic processes interact to create sedimentary successions. As is described in the Preface, this volume is based on the premise that each modern or ancient incised valley and its fill represents a natural experiment that was performed under a particular set of boundary conditions (i.e., tectonic setting, climate, sediment supply, physical and biological processes, etc.). Therefore, a careful comparison of valleys of different ages and locations should allow us to unravel the complex process–response relationships that occur in this multidimensional dynamic system. The purpose of this Introduction to the Volume is twofold. First, I attempt to summarize some of the common themes and major findings of the papers that make up the volume. In doing this, I make no claim of being comprehensive in my synthesis: some points that are important in the context of an individual study may not have fit well into this overview, whereas some minor points found resonance with similar points in other papers. In other words, reading this synthesis should not be a substitute for reading the excellent papers that constitute this volume.

Abstract Analysis of Quaternary successions from the Himalayan Foreland Basin suggests that tectonics, climate, and glacioeustasy have influenced valley and floodplain architecture in different parts of the Ganga Plains. Tectonic and climatic effects are implicated in valley formation near the Himalayan Front, where major faults are active. Climate was an important factor near the craton margin in the western plains, where tectonic activity is minor and subsidence rates are moderate. Age models for this region suggest that discontinuity-bounded sequences formed over timescales of 10 3 to 10 4 years in response to variations in monsoonal precipitation and fluid and sediment discharge in the rivers. Modern megafans and interfan rivers of the eastern plains are not incised, probably due to high sediment yields, low unit stream power, and high subsidence rates. Although long-term records are sparse, discontinuities are probably uncommon in this area. Channels on the Ganga–Brahmaputra Delta are not presently incised, but sea-level fluctuations generated thick late Pleistocene valley fills that extend several hundred kilometers inland. Many Himalayan and cratonic rivers across the area experienced Early Holocene incision in response to monsoon intensification following the Last Glacial Maximum, and brought a large sediment load to the delta and the Bengal Fan. Many reaches in axial parts of the Ganga system appear to have migrated progressively southward in the recent past, generating cliffs along their southern valley margins. Such systematic migration reflects collision of India and Asia and resulting uplift at the Himalayan Front. Climatically controlled sequences may be superimposed on this long-term valley migration, which should generate diachronous valley-base surfaces. Valleys on inland alluvial plains may vary from prominent to subtle over short periods and over distances of hundreds of kilometers, as well as avulsing periodically and migrating systematically.

Abstract The shape and infilling of the submerged parts of valleys incised along the southern coast of Brittany (France) have been investigated using very high-resolution seismics and a small number of piston cores. The valley location and morphology are found to be controlled mostly by submarine topography, which is marked by a well-developed fault zone that lies between the modern coast and a prominent basement-cored island and shoal complex located 5–15 km offshore. The faults controlled the shape of the valley networks and the amount of incision along the valley profile. They were probably active until the end of incision, because the valley thalwegs show scarps up to 10 meters high where they are crossed by these faults. The valleys were incised during the Quaternary lowstands of sea level, and most of the fill was emplaced during the last postglacial sea-level rise. The valley fills form a transgressive succession, consisting mainly of fluvial deposits at the base (possibly amalgamated from older sequences) overlain by tide-dominated estuarine deposits and capped by offshore muds. The most prominent internal surfaces are the tidal- and wave-ravinement surfaces. The valley-fill architecture is strongly dependent on the valley morphology (depth of incision, width of the valleys, and extent of estuarine intertidal areas). Estuarine deposits inside narrow and linear valleys are mostly aggrading muds, whereas those inside large and dendritic valleys dominantly comprise sandier, tidal-channel and bar deposits.

Abstract This paper presents a detailed VHR seismic analysis, ground-truthed by vibracore sampling, of the middle and outer segments of two modern incised-valley fills (the Charente and the Lay–Sèvre incised valleys) located on the French Atlantic coast, about 100 km north of the well-known Gironde incised valley. Despite strong similarities between these two incised-valley systems, including (1) small river drainage basins of less than 10,000 km 2 , (2) mixed-energy wave- and tide-dominated estuaries, (3) similar valley shape, and (4) two major disconnected submarine depocenters separated by a sediment starved area, their internal architecture shows major differences. To the south, the seaward depocenter of the Charente incised valley displays a typical succession including, from base to top: high-angle, subhorizontal (mixed sand and mud unit) and high- to low-angle reflector (sandy unit) units. The shoreward depocenter of the Charente incised-valley fill consists mainly of seismic units that display subhorizontal reflectors and is composed of mixed sand and mud, draping over small seismic units that display high-angle reflectors. To the north, the Lay–Sèvre incised-valley fill exhibits a rather different internal architecture, displaying mainly high-angle clinoforms composed of sand, covered by a mud drape in the shoreward depocenter. Summarizing our results, it appears that the northern Lay–Sèvre incised-valley fill is sand-dominated, whereas the southern Charente incised-valley fill consists of mixed sand- and mud-dominated deposits. Because those two incised-valley systems are located very close together (a few kilometers), it is postulated that they have experienced similar sea-level changes, vertical crustal motions, and climate changes. As a consequence, the observed differences in sediment infill must be related to variations in sediment supply. Because the drainage-basin areas of the rivers connected to those valleys are very small, and given that sediments include marine facies, it is proposed that variations in sediment supply signify different marine sources. A greater marine sediment supply has infilled the northern incised valley (the Lay–Sèvre incised valley) more than the southern (the Charente incised valley) because this northern valley acted as a trap for marine sediments derived from the southward-oriented littoral drift. By comparison, the Charente valley contains more mud derived from the Gironde estuary, located to the south. Such comparative study between two modern incised valleys belonging to the same basin shows that, despite similar tectonic, eustatic, and hydrodynamic controls, their infill can be very different as a function of variations in the type and amount of marine-derived sediment, controlled by both physiography and littoral drift. It shows a variant model for sediment-starved margins, which we name the rocky-coast estuarine model, where hydrodynamics and sediment transport are strongly controlled by bedrock morphology.

Abstract A seismic and multibeam sonar (swath) imaging study onboard the RV Southern Surveyor in Hervey Bay, east coast of Australia, revealed an incised valley (up to 50 m deep, 600 m wide, and at least 5 km long) cut into a Pleistocene shelf carbonate platform. The incision occurred in the Late Pleistocene, during the last eustatic sea-level lowstand. The subsequent transgression drowned the incision, but none of the fluvial or estuarine sediments that are typically deposited within incised-valley systems during passage through the coastal zone are evident on seismic. Instead, the seismic shows a low-amplitude fill with few internal impedance contrasts, suggesting a homogeneous, sandy composition. The incision is currently underfilled, and shows as a sinuous impression on the sea floor. Shelf sand dunes can be seen on the surrounding carbonate shelf migrating from the south towards the valley. At one location in the study area, the dunes migrate into the valley and appear to be filling it, because the dune crests can be traced across the valley margin and into the valley. Backscatter data from the multibeam survey also confirm the presence of extensive sand covering the valley floor. Scours can be seen adjacent to the steep valley walls, indicating the presence of strong tidal currents, which could be a mechanism for redistributing sand inside the valley. Implications for existing facies models of incised-valley systems are significant, because the filling of this incision did not occur in the coastal zone during transgression. Filling by shelf sediments could occur at any time during the sea-level cycle when the shelf and valley are not subaerially exposed. Depending on the dominant shelf process responsible for filling the valley, the valley-fill deposits can be anything from homogeneous sand, as in the case described here, to highly variable shelf facies, which would complicate any potential reservoirs in such a valley fill.

Abstract The development of an estuary and the accumulation of organic matter in it are strongly influenced by variations in sea level and river discharge related to climate changes. We examined the relationship between development of a Holocene estuary and the sedimentation of organic matter. The study estuary, on the Niigata Plain, central Honshu, Japan, is wave-dominated and microtidal, with a barrier island and bay-head delta. We took two 50-m-long cores, one from an area adjacent to major river discharge and another from the basin margin. Estuarine environmental and sea-level changes were reconstructed using facies analysis. Bottom conditions, which affect the preservation of organic matter, were also examined by means of facies and geochemical analyses, including the TS (total sulfur) content and C/S (carbon to sulfur) ratio. Organic constituents of the estuarine sediments were examined with reflected-light fluorescent microscopy and geochemical analyses, including TOC (total organic carbon), C/N (carbon to nitrogen) and stable carbon isotope ratio (δ 13 C) of organic matter. Late transgressive and highstand estuaries are especially suitable for the preservation of organic matter, because they are enclosed by a barrier island that promotes anoxic bottom conditions. Nearly all of the organic matter preserved in this estuary is terrestrial origin, and a part of it is preserved as NFA (nonfluorescent amorphous organic matter), which forms under anoxic conditions. The NFA formed during the highstand stage in the basin-margin area, whereas an even greater abundance of coarsegrained organic matter accumulated during the late transgressive stage in the area with major river input. During the late highstand stage, coarse-grained terrigenous organic matter, including vitrinite and cutinite, was deposited in both the marginal area and the river -mouth area. Industrial minerals and rocks are Earth materials utilized because of their characteristic physical and/or chemical properties and not because of their metal content and which are not energy sources. According to this definition they cover a broad spectrum of minerals and rocks which form at all geological environments. The relative importance of industrial minerals to the economy of the various countries reflects the economic maturity of that country and today they constitute the most important raw materials exploited in the developed industrialized countries. The unit value of many industrial minerals is small compared to that of metals and depends on the geographic site from which they are extracted, i.e . they have a large place value. The small unit value also dictates the extent of processing and beneficiation. As they are used by the industry because of their physical and chemical properties, different industrial minerals may often compete for the same applications. In some cases the industrial practice requires production of synthetic industrial minerals, such as zeolites and diamonds, with tailored properties and therefore high added value. Due to increasing environmental awareness, there is need for utilization of waste materials from mining activities, which are also in the mineral form and can thus be considered as industrial minerals. The economic significance of industrial minerals is expected to increase further in the future.

Abstract An extensive data set of over 10,000 km of high-resolution seismic data and over 300 cores and platform boring descriptions has been collected in the northwestern Gulf of Mexico from the Rio Grande to the Western Louisiana Shelf. The incised valleys that formed during the last fall and lowstand of sea level (between 18 and 20 ka) were mapped using this dataset. The climatic setting for the study area ranges from semiarid to humid, and the margin physiography ranges from broad low-gradient shelves with a distinct shelf break to ramps. This study has led to several important observations about the morphology and fill of incised valleys on passive margins. First, one of the most important factors controlling valley morphology is shelf physiography. Generally, if a distinct shelf break exists, incised valleys extend to the shelf break. Both the Rio Grande (semiarid climate) and the Colorado (subhumid climate) valleys exhibit this morphology. On ramp margins, such as the central Texas shelf, incised valleys shallow seaward and often do not extend to the shelf break. Two major morphologies are also seen in the valleys of the Gulf of Mexico. These include terraced valleys and simpler V-shaped or U-shaped valleys. Rivers of small to moderate size are more commonly terraced as a result of their tendency to stay in the same location throughout the fall in sea level. Generally, large river valleys are V-shaped or U-shaped in cross section. This is because larger rivers are more inclined to avulse at a site above the landward limit of incision and to abandon their terraced highstand valleys. The facies architecture of incised-valley fills is a function of the systems tract in which the valley was filled and the rate of sediment supply versus sea-level rise. Valley-fill sediments deposited during a lowstand are generally coarser grained than fill deposited during the transgression, and transgressive fill exhibits a fining-upwards succession. Long-term sediment supply is controlled mainly by climate and drainage-basin size. Lastly, the relative influence of fluvial, wave, and tidal processes on valley infilling vary as the morphology of the valley, rate of sea-level rise, and sediment input vary. These combined effects result in valley morphologies and fill architectures that are more complex than existing incised-valley models indicate. We suggest a revised classification of incised valleys based on the proportion of fluvial versus estuarine and marine fill. The two end members are overfilled and underfilled with respect to fluvial sediments. Underfilled systems fit the classic incised-valley models set forth in earlier studies, but overfilled systems are not highlighted in these models. Overfilled valleys do not contain central-basin (open, middle, or lower bay) or marine facies. Overfilled valleys are commonly associated with deltas throughout the eustatic cycle, including the transgression, and exhibit a complex internal architecture of many diastems that do not represent sequence boundaries.

Abstract Four sediment-rich incised-valley systems in China, which underlie the Luanhe fan delta, the Changjiang delta, the Qiantangjiang estuary, and the Zhujiang delta, are examined based on over 800 drill cores. These four systems are of different shapes and sizes, and are located in different tectonic zones with different tide regimes ranging from microtidal to macrotidal. Because of the abundant fluvial sediment supply and relative dominance of river forcing, sediments in the modern Qiantangjiang and paleo-Changjiang estuaries display a fining-seaward trend. This is different from the classical estuarine facies model of coarse bay-head delta, fine central basin, and coarse bay-mouth deposits. The abundant sediment supply also results in the presence of relatively thick transgressive successions in the overall incised-valley fill. The transgressive succession constitutes more than 50% of the total strata thickness and approximately 60–70% of the total sediment volume within the valley. The river-channel facies in the transgressive succession was formed by retrogressive aggradation during postglacial sea-level rise. Retrogressive aggradation extends far inland beyond the reach of flood-tidal currents, and, therefore, no marine signatures were found at the lower portion of the incised-valley fill. The regressive succession in the incised-valley systems consists of fluvial facies or tidal facies and deltaic facies, and was developed as the estuary filled and evolved into a progradational delta. The tide-dominated facies tends to be developed in the apical areas of funnel-shaped estuaries, such as the modern Qiantangjiang and paleo-Changjiang estuaries. Four generalized facies successions (FS-I, FS-II, FS-III, and FS-IV) are recognized within the valley fill. An idealized schematic incised-valley fill contains FS-I at the coastline region, FS-II and FS-III in the middle, and FS-IV at the apex area of the delta or estuary, reflecting a decreasing marine influence and increasing terrestrial contributions. The preservation of multiple incised-valley-fill sequences is controlled by the different regional tectonic characteristics. Vertically superimposed valleys are preserved beneath the Changjiang delta, whereas the Luanhe fan delta is characterized by lateral juxtaposition of valley as a result of channel switching.