Deposition of deep-water fan systems is, in part, influenced by a variety of shelf margin and slope processes that affect the sediment pathways into the receiving basins. Shelf and slope seafloor topographic changes that resulted from tectonic movement, mobile substrate deformation and/or relative sea level fluctuations, may lead to switching of the sediment pathways leading to deep-water basins and result in depositional pulses of shelf and slope material that interrupt the background pelagic and hemipelagic sedimentation in different areas through time. The sediment pathways of the Permian deep-water deposits in the Tanqua and Laingsburg subbasins seen in outcrops in the southwest corner of the Karoo Basin, South Africa, have been influenced by fluctuations in seafloor topography caused by tectonic forces associated with the adjacent fold thrust belt. The two subbasins have geologically near-contemporaneous formation and filling, and in part contain deep-water sediments. Studies on these deep-water deposits have allowed reconstruction of the shelf and slope environment. Tectonic compression in the area has led to the formation of a basin floor high (anticlinorium) that separates the subbasins and influenced sediment transport. The Tanqua subbasin has developed into a broad, open basin that received five stacked submarine fan systems, while the Laingsburg subbasin has built into a deeper, longer and narrower basin that also has received five stacked submarine fan systems. Petrologic and microprobe analysis of the sandstones in the submarine fan systems indicate that they have come from a common source area that is an extended distance away (as great as 400 km). The subbasins, most likely, share a single shelf edge canyon and slope transportation system that involves enough length to allow for switching of the slope pathways through the evolving topographic highs and lows over time.

Understanding the interactions of the source-to-sink sedimentary system is necessary to place a deposit in a receiving basin in its proper depositional perspective. This is true for any part of the source-to-sink system, whether it deals with fluvial, deltaic, shelf, slope, or deepwater, especially when the sink is now in the subsurface. One should look updip as well as down-dip to understand better the environment of interest. Critical information to classify the variety of submarine fans, such as the range of grain size and the distribution of sand, can be found in the time-equivalent deltaic environment at the shelf margin. Four major factors can be identified that influence all parts of the source-to-sink system: tectonic activity, climate, relative sea level fluctuations, and sediment characteristics. Tectonic activity, both local and regional, comprises the primary factor. Pre-depositional tectonic movements guide the location and elevation of the sediment-providing mountains, climatic conditions for weathering and precipitation, types of subaerial transport, development of the coastal plain and its delta (if any), the shelf width, slope characteristics, and the receiving deep-water basin characteristics. Climate influences several attributes, including sea level fluctuations and sediment transport to the coast and beyond. Sea-level fluctuations, controlled by large-scale tectonic activity and/or climatic changes, influence subaerial and coastal processes. During rising, high relative, or global sea level, coastal plains become submerged and sediments are stored on the continent and the shelf. During the lowering and initial rising stages, sea level can result in shelf-edge deltas or the feeding of sediment directly to a deep-water basin. The maturity of the sediment is strongly influenced by the type and duration of subaerial transport, where the majority of the mechanical and chemical weathering takes place. During subaqueous transport, significant amounts of clay-sized sediment facilitate transport of fine-grained sands far into the ocean basins. Whether deep-water sediments are coarsegrained or fine-grained, the coastline dictates if the feeding sediment source is canyon-fed or delta-fed. Shelf margin deltas are typical for fine-grained sediment and are normally located on wide, low-gradient shelves. Lateral switching of the delta establishes a new location for the entry point of the sediment to a deep-water basin. Shelf margin deltas on narrow shelves do not always exist during low sea-level periods.

Abstract Outcrop sections containing excellent physical and biogenic sedimentary structures within the Late Permian Ecca Group are exposed within the Tanqua Karoo that show the transition from shelf margin delta through to slope and basin floor fans. The Tanqua submarine fan complex comprises six regionally distinct fan systems, five of which form a progradational stack with the sixth fan, to the south, downlapping onto the fifth fan. Progradation of the deltaic deposits across the basin has been in response to a decrease in accommodation space created by relatively high rates of sedimentation within the foreland basin setting. The sedimentology and sequence stratigraphy of the Hangklip Fan represents a shelf margin delta feeding downdip slope fan deposits. Wave ripples, swaley cross-stratification and trace fossils, including Gyrochorte , suggest substantially shallower depositional conditions than slope fan deposits, which are devoid of such features. Erosional slump scars, cutting into laminated shale with chaotic infill of sand intraclasts, point toward slope depositional processes that are not in evidence in the underlying submarine fan deposits.

Abstract The southwestern part of the Karoo basin, South Africa is comprised of two mountain chains (Figures 1,2). The southern branch (Witteberg Swartberg Range) runs east-west, and the western branch (Cedarberg Range) is more or less north-south. Where the two meet is a northeast-trending syntaxis with two anticlinoria. This structural area encloses two foredeep areas, known as the Laingsburg subbasin and the Tanqua Karoo subbasin. The east-west running Laingsburg subbasin is a typical elongated foredeep. Later tectonic activities tilted this basin, with the result that the layers are close to vertical. Between the western branch and the anticlinoria is the location of the Tanqua Karoo subbasin. The outcrops of this basin now cover an area of 650 km2 (250 mi2). The basin is Permian age ( Figure 3 ; Wickens and Bouma, 2000 ). Gradual sinking of the basin has resulted in a 7–8-km (4.36–5.0-mi)-thick package of younger deposits overlying the deep-water sediments. A later rebound eroded overburden, with the result that the Permian deep-water deposits became exposed. The outcropping area is about 34 km (21 mi) long and has no tectonic dip in the north-south direction. The visible width varies from 8 to 12 km (5–7.5 mi), and shows 1–3° tilt to the east. Lack of vegetation exposes large outcrops along the western and southern sides, as well as in the middle along the Gemsbok River ( Figure 5 ). The outcrops make it possible to observe the depositional changes in the downslope direction. The subbasins formed during the Permian compressional collision

Abstract The eastern 2 km (1.2 mi) of Fan 3 outcrops represent channel deposition at the base-of-slope (Figures 1, 2). Figure 1 shows details of the contacts between channels while Figure 2 shows approximately 1200 m (3937 ft) of the outcrop with multiple stacked and laterally offsetting channels that are best described as nested channels. The Ongeluks outcrop area is the transition from the feeder canyon to the deep-water basin. As the canyon flares out and the gradient lessens, density currents move from side to side, filling topography and cutting into pre-existing channels. There are 19 partial channels in the outcrops; most are less than 300 m (967 ft) in width (see Figure 2 ; the summary tables). Many of the sand-filled channels have shales or silty shales lining the channel bases, but in some cases local scour has removed the shale leading to sand-on-sand contacts. The silty shales also occur within the channels and most are laterally discontinuous. The measured sections and paleocurrent directions for this outcrop are from studies by O. van Antwerpen (1992).

Abstract The Fan 5 outcrops at Bloukop Farm include channel and thin-bed deposits. Initially, this outcrop was interpreted as consisting of middle-fan channel sandstones overlying thin-bedded outer-fan sheet sandstones. Closer examination (and clearing of the outcrop face) revealed that the massive channel sandstones were locally coeval with several of the thin beds (see Figures 4, 5) suggesting channel and levee deposition (Bouma and Wickens, 1994). Kirschner (1999) conducted a detailed study of the area (also reported in Kirschner and Bouma, 2000) that supported this interpretation. Two channels were recognized in the outcrop. channel 1 is the lower channel that shows the connectivity of two of the levee thin beds with the channel sandstones. Most of the other beds are truncated by the channel illustrating variable times of channel cutting and thin-bed deposition. Both of the channels are shallow and wide, and they mostly have erosional contacts with the underlying deposits. And although the channels commonly overflowed (sand-rich sediments form poor and low-relief levees), direct contacts between the channel and thin beds are rare due to deposition, scour, and subsequent fill. The average grain size of the channel deposits is slightly larger than the levee deposits. Paleocurrents of ripples indicate a northerly transport direction within the channel while the layered levee deposits have a divergent 35° offset direction on both sides of the channels. Common sedimentary structures include parallel laminations, current ripple laminations, and climbing ripples; climbing ripples are common at this location ( Figure 5 ).

Abstract Kanaalkop, located on the Klein Gemsbok Fontein Farm, contains parts of three of the five fans of the Tanqua Karoo. Fans 1 and 2 are thin and represent parts of distal fans. Fan 3, the subject of this paper, occurs in a middle fan location ( Figure 1 ). The Fan 3 outcrop includes a complete channel cross section and levee-overbank deposits of three precursor channels. The most important part of the outcrop, the fill of the upper channel, is 508 m (1667 ft) wide and 19 m (62 ft) thick in the center. The sandstone layers in the axis of the channel are amalgamated. In the channel margins, the fill thins and the sandstone beds become interbedded by shales. The channel center also has two small erosional scours: a 0.75 m (2.5 ft) cut on the left and 0.50 m (1.6 ft) cut on the right. The center of the channel is mostly parallel to the underlying bedding. Thin beds underlie the entire channel complex ( Figure 2 ). Work by Kirkova (1998) indicates that these thin beds represent overbank deposits from three other channels (not present in this outcrop). The three intervals are labeled a, b, and c in Figure 2 . Note that there are more thin beds underlying the margins of the main channel where the channel thins laterally. Overall, there are general fining- and thinning-upward trends in these units and there is also an offset (possibly due to compensating bedding) in the thickening and thinning of the thin-bedded units.

Abstract Excellent exposures of Fans 3 and 4 in an L-shaped outcrop are present at the Klip Fontein Farm. Some parts of Fan 5 can also be seen. The east-west arm is 1800 m (5900 ft) long and the north-south arm is 1000 m (3280 ft) long. Fan 3 is fed from the south, making the east-west arm a strike section. Fan 4 is fed from the west and shows a dip section on the east-west outcrop. Fan 5 is fed from the south. The outcrops are a classic example of a high net-to-gross, fine-grained, amalgamated sheet package deposited in the outer fan. The strike and dip sections show very similar features. Fan 3 is about 13.5 m (44 ft) thick, and Fan 4 is 54–60 m (177–197 ft) thick. The shale separating the two fans has a thickness of about 16 m (54 ft). Both fans represent outer-fan sheet sands (depositional lobes). This paper will concentrate only on Fan 4. At first view, the sandstone layers appear to be parallel. However, detailed drafting of shale contacts shows rather flat bottoms and the convex upper contacts show a gradual lateral thinning of the sandstones. Fan 4 shows laterally continuous sandstone and shale beds and occasional amalgamation in the center of succeeding sandstone beds. The thin interbedded shales are comprised of alternations of very thin sandstones and shales. Plant fragments are common on the top of most silt-rich shale laminae. Thickening-upward sequences and some incomplete Bouma sequences can be detected. Paleocurrent directions vary widely due to bathymetric compensation.

Abstract Fan 3 on Kleine Riet Fontein Farm shows two interesting outcrops separated by shale scree. At the southern outcrop, channel fills can be observed, and in the northern outcrop are levee-overbank deposits with a number of thicker, massive sandstones with net-to-gross (N:G) near 1.0 that can be recognized by their light color. They are interpreted as crevasse splays. The north-south-oriented outcrop probably makes only a small angle with the overall north-south paleotransport direction of Fan 3, making it difficult to obtain a good cross view of the channel margins. Nevertheless, the outcrop shows important parts of channels and levees belonging to a fine-grained turbidite system. The location of both outcrops is shown in chapter 75, this volume. Figures 1A-C reveal three channels separated by thin shales and very thin sandstones. The shaly separations thicken to both sides, indicating that the erosion of the underlying channel was often strongest in the central zone of the channels (see upper channel, Figure 1A ). This photograph shows thin-bedded, sand-rich layers separated by silt-rich shales. The picture in Figure 2 does not reveal the thickness of the sand layers. Figure 3B shows four light-colored, massive sandstone layers, which are interpreted as crevasse splays. The massive central part of each channel shows some bedding when observed close-up. Layers are separated by thin shale and/or thin sandstone layers. Both sides of the massive part become thinner layered and thin-bedded. A succession of sandstones and silt-rich shales becomes more distinct toward the ends.

Abstract Although the cleanly visible portion of the outcrop at Kleine Gemsbok Fontein Farm is quite small (36 m [118 ft] long) and lacks third dimensionality, it is a good example of the transition from thicker amalgamated sheet sandstones to thinner sandstones in a very short distance. In addition, details of amalgamation are well preserved in this high net-to-gross, fine-grained outer-fan setting. The Fan 2 outcrop, interpreted as outer-fan sheet sandstones, is an example of local connectivity in an overall nonamalgamated outer-fan layer sheet sand deposit (Rozman, 1998, 2000; Bouma and Rozman, 2000). This small outcrop, orientated northeast-southwest, shows massive, amalgamated sandstones that change laterally to bedded silty shales and thin sandstones. Some of the layers show vertical connections where the shale is locally eroded and filled with sandstone ( Figure 1 , arrows point to the locations). This outcrop is oriented at 45° with respect to the paleocurrent direction. No third dimension is available to determine whether these sand-on-sand contacts are localized or extensive, or in which direction they are oriented. If they are extensive, they may represent filled gullies (furrows).

Abstract The two authors explain how and why the Grès d'Annot successions were chosen for their influential studies in the context of the 1960s and the 1980s. Arnold Bouma explains the origin of the Bouma Sequence in the 1960s, while Christian Ravenne focuses on the significance of the area as analogues of deep-sea fans and seismic stratigraphy in the 1980s. Ravenne recalls the main results obtained at that time: palaeogeographical maps, interpretative and synthetic sections, the spectacular onlap relationships at Chalufy, the strong interaction between seismic interpretation and field data, and the importance of large failures/collapses on the continental slope for the initiation of density surges.

Abstract Four main controls (tectonics, climate, sedimentary characteristics and processes, and sea-level fluctuations) commonly interact with each other and do so at varying intensities. This results in a wide variety of basin types and shapes, timing of transport within the sequence stratigraphy framework, transport and depositional processes, grain size ranges, and distribution of sediment within a basin. Two major end members of turbidite systems can be recognized: coarse-grained/sand-rich and fine-grained/mud-rich. Coarse-grained fans typically belong to active margin settings. They prograde gradually into a basin and show a decrease in thickness and grain size in the downflow direction. The sediment source is near the coastline, and the turbidite basins are commonly small to medium in size. The fine-grained fans occur on passive and active margins, prograde rapidly into a basin, and deposit most of the input sand in the distal fan as oblong sheet sands. Tectonically confined basins normally have their sediment source nearby, and therefore will be filled with coarse-grained fans. Most of the open (unconfined) basins are medium to large in size, have their sediment source far from the coast, and therefore lose the coarser fractions during continental transport. Diapirically controlled basins are small- to medium-sized confined basins that have a fine-grained turbidite fill, but may not reveal the bypassing of the majority of the sand to the outer fan because of the abundance of sediment transport to the basin.

Abstract Siltstones, mudstones and shales have been studied mainly with regard to general transport-deposition processes and clay mineralogy. A small group of investigators, with differing backgrounds, have worked on these fine-grained deposits. While there have been a number of resulting publications, they are spread out over a wide array of geological literature. Recent studies on deepwater deposits from cores and outcrops indicate that the presence of finer-grained deposits greatly affect the fluid flow properties of deepwater reservoirs. Further analysis indicates that the majority of these finer-grained deposits have a large silt component and are closer to siltstones rather than mudstones, commonly called shales. Studies on these deposits have indicated that they are often comprised of graded fine silt laminae sandwiched between films of clay minerals, quartz dust and organics. Characteristics and rock properties of these deposits, which resulted from a variety of depositional processes, are just beginning to be understood. Depending on the transport-deposition processes, the architecture of the deposit will have different 3D extents and continuity as well as varying rock properties. Stratigraphic prediction of the position and dimensions of the fine-grained beds can indicate whether the deposits will be a barrier or a baffle to fluid flow or a possible reservoir for natural gas. Minor variations in depositional style and other characteristics can result in more differences than presently assumed.

Abstract A symposium dedicated to fine-grained sediments (shales, mudstones, and siltstones), as seen from various directions, was organized by the authors along with William Bryant (Dept. of Oceanography, Texas A&M University) and held at the 2002 GCAGS Annual Meeting in Austin, Texas, on October 30, 2002. The term ‘shales’ is widely used and misused. Although over 60% of all sediment present on Earth fit the term shale, very few people work on these deposits. The few researchers active in this field vary widely in their interests and the type of journal they publish in. This results in earth scientists at large not being familiar with what is known to date. For that reason we decided to organize a symposium to start bringing these sediments more the to forefront. A total of eleven presentations were given to an audience of over 30 persons. The symposium was well received and the idea for a follow-up was strongly supported. Every participant received a hard copy and a CD-ROM. In addition to the written papers the CD also contains a copy of all the additional illustrations used by the speakers. A copy of the CD can be obtained from the SEPM office (SEPM, 6128 East 38 th Street, Suite 308, Tulsa, OK 74135-5814. Tel.: 918/610-3361 or 1-800-865-9765).

Abstract Fluid muds are high-concentration near-seabed suspensions of fine sediments, and have been recognized in coastal sedimentary systems for many years. However, in the past decade, fluid-mud development and transport have been identified in an increasing number of settings as important mechanisms for marine dispersal of fluvial sediments. It has been shown that the combination of high-energy benthic hydrodynamics and sufficient fine sediment can result in cross-shelf gravity-driven flows (on very low slopes) that can blanket hundreds of square kilometers to thicknesses exceeding 10 cm. The sedimentary fabric that results from gravity-driven flows consists of a stacked pattern of predominantly fine-grained, fining-upward packages. The resulting morphology of the shelf can be a clinoform, with maximum deposition occurring on the foreset (convex-upward) region. The western Louisiana inner shelf has been experiencing fluid mud deposition in response to increased fine sediment supplied by the Atchafalaya River since ∼1950’s. A review of observations collected during recent studies of the Eel and Fly rivers, and their similarities to the Atchafalaya shelf indicate that wave-enhanced gravity driven flows are responsible for the sedimentary features and clinoform morphology present along the Chenier plain coast of Louisiana.

Abstract The continental margin of the northern Gulf of Mexico is characterized by a very complex morphology due to the interactions between sedimentary and halokinetic processes. Sediments deposited on the margin during the last glaciation provide an excellent opportunity for the study of depositional processes of fine-grained sediments in a structural complex deep-water environment. This study is based on detailed analysis of long sediment cores and high-resolution geophysical data from two areas of the northern Gulf of Mexico: Bryant and Eastern Canyon Systems and the Atlantis Discovery. At least three sedimentary provinces existed on the continental margin during the last glaciation. The Mississippi Canyon and Fan resulted from the building of the Mississippi River delta at the shelf-margin during the last glaciation. Turbidity currents flowing through the Mississippi Canyon at this time contributed to the continued development of the preexisting Mississippi Fan. The Texas and Louisiana continental slope province characterized by numerous intraslope basins. Deposits from the last glaciation consist of hemipelagic sediments interbedded with finegrained (silty-clay to clayey-silt) turbidites that thin and fine downdip. These deposits were produced by low-density turbidity currents that resulted from the depositional segregation (deposition of the coarsest material at the most proximal locations) of large turbidity currents initiated on the outer shelf and/or upper continental slope. Thick (up to 40 m), structureless mud deposits (unifites) on the floors of intraslope basins most likely resulted from the partial deposition of long-lasting (1.5-3 months), low-density turbidity currents. The continental rise and lower continental slope province of the northwest Gulf of Mexico has fine-grained, layered sediments that are siltier than those of the fine-grained turbidites from the continental slope province, and occasionally reveal a lenticular to wavy nature. The layered sediments are interpreted as deposits of turbulent sediment flows whose site of deposition is controlled by westward flowing bottom currents. The currents pirate the finer-grained sediment load (upper part and tails) of turbidity currents flowing through the Mississippi Canyon to the Mississippi Fan and relocate them within this province. Turbidity currents were most abundant between 32-28.5 ky BP and 28.5-21.5 ky BP. The first time interval coincides with the development of a major deglaciation event that led to highly increased river discharges. The second time interval coincides with the drop of the sea level to the shelf edge, and the production of shelf margin deltas during the last glacial maximum.

Abstract The Upper Cretaceous Lewis Shale in the Greater Green River Basin provides outcrop exposures of deepwater deposits that are linked to updip shelf margin deltas. A 6m thick section of thin-bedded, fine-grained mudstones along a well-exposed gully has been measured and described in detail, and grain-size of individual laminae have been analyzed by laser particle size analysis. The outcrop consists of three facies. In the upper 3m of the section, a gray laminated, graded mudstone is the dominant lithology. Stratigraphically beneath this, the laminated, graded mudstone and tan, massive mudstone are interbedded. The laminated, graded mudstone encases siltstone beds which increase in thickness upward from 0.3 to 10 cm and which are also graded. The size ranges for the facies are: massive mudstones (6.4μm – 10.0 μm), laminated, graded mudstones (6.5μm -37.97μm), and siltstone (45.75μm – 55.13μm). At outcrop scale, two styles of mudstone grading are observed. The first type is a fining-upward sequence that typically ranges in thickness from 2.5-5cm. The second type is a compound of a basal coarsening-up unit and an upper fining-up unit, which combined are typically 3.8cm thick. At the mm+ scale, laser grain size analysis of individual laminae and groups of laminae spaced mm’s apart indicate both fining-upward and coarsening-upward laminae sets are present. The fining-upward laminae sets are interpreted as the result of deposition from waning flow from dilute turbidity or hyperpycnal flows. The combined graded sequence described in outcrop, and coarsening-upward laminae sets identified from laser grain size analysis are typical of hyperpycnites found elsewhere in modern deep marine environments. They are believed to be the result of progressive increase in river discharge during rising and peak flood stage (upward increase in grain size), followed by waning flow after the flood begins to abate (upward decrease in grain size). The results reported here are preliminary, and additional research is required to fully confirm or modify these conclusions.

Abstract Observations by transmission and scanning electron microscopy (TEM and SEM) of surficial sediment microfabric along with quantitative geochemical tests of organic matter from continental margin deposits reveal important fundamental interrelationships of material properties and processes during diagenesis of mud to shale. Fine-grained surficial muds possessing ≥2% total organic carbon (TOC) and ≥5% smectite commonly have very high porosities (≥90%), low wet bulk densities, and very low effective stresses that are consistent with minimal dewatering and consolidation in the upper few meters subbottom. These muds are characterized by random orientation of clay domains and marine organic material in the form of mucopolysaccharides and living microbiota that bridge between clay particles and aggregates and commonly appear to fill pore space in 2-D EM views. These fine-grained, organic-smectite-rich, clayey muds consolidate to very low porosities (≤30%) under relatively low overburden stress (∼1000 kPa or ∼120 m below the seafloor). In contrast, similar smectite-rich clayey muds possessing ∼0.5% TOC consolidate to approximately the same porosities but at loads of at least six times the overburden stress. In both cases, the microfabric observed by TEM and SEM following consolidation reveals a strong preferred clay particle orientation normal to the direction of the effective stress indicative of significant anisotropy in the permeability. Sandy clayey silts (62%-75% silt) that possess TOC contents of 1.3% to 4.2% consolidate remarkably different from the organic-rich clayey muds. The sandy clayey silts display porosities well above 38% at high consolidation stresses and show significant resistance to consolidation at high stresses probably due to grain-to-grain contact of the sand and large silt particles. Despite the exceptionally high depositional porosities of the sandy clayey silts, these muds, even those having high TOC, dewater significantly less under large consolidation stress compared to the organic-smectite-rich clayey sediments. A general correlation is found in the fine-grained sediment between the amount of smectite and the amount of organic material in the sediment. Studies have shown that smectite has a strong affinity for organic material and correlates well with water content, high porosities, and low wet bulk densities. Thus, the presence of organic material (≥2% TOC) largely controls the microfabric during early sediment diagenesis and has a significant impact on post depositional consolidation. The microfabric, mineralogy, and organic content of muds largely control the porosity and permeability of not only the sedimentary analogs of mudstone and shale but also largely determines the ultimate properties of the rocks in the geologic column. Noteworthy is that many highly fissile shales are rich in organic material. It is postulated that the presence of large amounts of organic material ( i.e ., ≥2% TOC) in sediments during consolidation and early diagenesis may ultimately affect the mechanical properties and response of the mudstones and shales during deep burial and tectonic stresses at passive and active margins and in epicontinental seas. The insoluble organic component of sedimentary rocks, kerogen, can be differentiated on the basis of the amount of hydrogen and carbon present in the material. The different types of kerogen influence not only the consolidation behavior but also may affect the development of fractures and migration pathways during continental margin evolution. Upon thermal maturation, some geochemical types of kerogen produce oil (types I and II), while type III produces natural gas. Kerogen of mainly terrestrial origin (type III) consists largely of negatively-charged polymers that inhibit adsorption of the organic matter onto negatively-charged clay mineral surfaces. Type I and II kerogen, which are of marine origin, are more readily adsorbed onto clay particles and can be expected to influence the development of geotechnical properties differently than kerogen of terrestrial origin. The kerogen types would be expected to behave differently in different stratigraphic sequences and perhaps even enhance fracture healing, retard stress fracturing, or conversely, promote fracturing during deformation. Thus, the clay microfabric, organic content, and isotropy/anisotropy of a mudrock or shale largely determines the stratigraphic formation functionally in terms of its role as either a petroleum source rock, reservoir seal, or migration pathway. Continental margin tectonic patterns result from regional stress fields imposed on stratigraphic sequences developed with different properties characteristic of the environments of deposition. The rock types developed and the productivity of the source rocks at depth appear to primarily depend upon the mineralogy, grain size distribution, organic material, microfabric, stress regime/depth of burial, and probably the differences in the material properties (porosity, permeability, strength, etc. ) of the sand, mudstone, and shale in the stratigraphic sequences.

Abstract Stratigraphic correlation of deep water siliciclastic sequences generally is based on biostratigraphic, palynological, and lithologic markers. However, in sequences that are barren of, or have limited fossil assemblages along with inconclusive lithologic correlation, the chemical composition of the silts and shales in the stratigraphic section can be used to determine potential tie points in the basin fill. This chemical composition can be used to correlate sedimentary packages across a basin or even potentially between adjacent basins. Successfully used, correlation of the chemical composition of shales and silts can give a fuller understanding of the timing of the basin fill and depositional environments.