The Application of Chemostratigraphic Techniques to Distinguish Compound Incised Valleys in Low-Accommodation Incised-Valley Systems in a Foreland-Basin Setting: An Example from the Lower Cretaceous Mannville Group and Basal Colorado Sandstone (Colorado Group), Western Canadian Sedimentary Basin

摘要: Changes in the bulk inorganic geochemical composition of both sandstones and silty mudstones taken from conventional cores are used to subdivide Lower Cretaceous Mannville Group overlying Colorado into chemostratigraphic packages units. The broadly equivalent lithostratigraphic formations whereas geochemical units represent finer-scale informal stratigraphic subdivisions that occur within formations. The Formation, Upper Basal Sandstone (an unit at base Group), Joli Fou Formation. changes, which enable each unit, or package, be geochemically fingerprinted, primarily related changes mineralogy,which turn appear coincide with sediment provenance basin architecture. These packages, formations, can considered result first-order whole-rock geochemistry. The units incised-valley-fill sequences units, here it is shown have a unique signature. Three present latter intervals, oldest lie Valleys incise deposits termed lower sandstones. youngest valleys top upper sedimentary these incised chemically distinguished one another, even where sandstone-on-sandstone contact single wellbore. incised-valley fill recognized as second-order variations referred Stacked observed Formation been subject previous work, all signature also units. The succession, sequence boundary. By enabling clear identification above below boundary, technique chemostratigraphy has direct application aiding correlations low-accommodation settings.