Variations in Fluvial Style as Revealed by Architectural Elements, Kayenta Formation, Mesa Creek, Coloralk), USA: Evidence For Both Ephemeral and Perennial Fluvial Processes
Michael H. Bromley, 1991. "Variations in Fluvial Style as Revealed by Architectural Elements, Kayenta Formation, Mesa Creek, Coloralk), USA: Evidence For Both Ephemeral and Perennial Fluvial Processes", The Three-Dimensional Facies Architecture of Terrigenous Clastic Sediments and its Implications for Hydrocarbon Discovery and Recovery, Andrew D. Miall, Noel Tyler
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Architectural studies in the Kayenta Formation (Lower Jurassic) of the Colorado Plateau reveal the characteristics of two types of sandstone body, that reflect both ephemeral and perennial fluvial processes. The first type is composed of high-regime horizontally-laminated sandstone, forming multiple-event Storys up to 8 m thick, deposited by flash floods. The second type is composed of planar cross-beds, deformed parabolic cross-beds and massive sandstone formed under low-regime flow from a perennial river during high stage.
The style of deposition is dependent upon the degree of confinement within the boundaries of the channel system in question. Where confinement was dominant, sedimentary fill often reflects the geometry of the containing channel. Paleocurrent distribution reflects the depositing flow conditions in confined bodies. Horizontally-laminated units show strongly unimodal currents, whereas the heterolithic confined units show a wider scatter.
Where flow was unconfined (during high stage, when thalwegs were inundated), the resulting deposits are broad sheets interfingering with underlying confined sandbodies. A zone of interdigitation displays sharp changes in paleoflow direction within the same stratigraphic horizon, resulting from the simultaneous action of confined and unconfined depositional processes. The interdigitation records the incremental abandonment of channels, as large unconfined barforms encroached on them during high stage.
Discharge variability is inferred from lithofacies composition; variable but perennial discharge shows a wide range of lithofacies, including clay drapes resulting from minimum, sluggish flow. Flashy discharge shows only two lithofacies types, those representing low-regime waxing and waning flow and those representing high-regime peak flow. Clay drapes are absent
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The Three-Dimensional Facies Architecture of Terrigenous Clastic Sediments and its Implications for Hydrocarbon Discovery and Recovery
While there has been much interest in recent years in concepts of sequence stratigraphy, this book focuses on stratigraphic units that are, in general, an order of magnitude smaller than sequences. A knowledge of such architectural detail is of considerable significance in the development of detailed, scaled facies models for depositional environments, and is of paramount importance in the efficient design of advanced petroleum recovery projects. This book is the outcome of a SEPM Research Symposium held at the annual meeting of the Society in San Antonio, Texas, April 1989. The intent of the meeting was to bring together modern research on facies architecture, and to apply this research to the investigation of reservoir heterogeneities and production problems.