AAPG Foundation 2019 Grants-in-Aid Projects

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Variability in sedimentary provenance from proximal to distal foreland basin fill: implications for sediment routing into and within the Cretaceous Western Interior Seaway


Are there significant differences in sedimentary provenance between linked depositional environments? Detrital zircon geochronology is commonly used to identify provenance signatures in vertical transects though sedimentary basins, which is used to infer both local- and regional-scale changes in sedimentary transport though time. However, the potential for differences in provenance between time-equivalent depositional environments, even over small distances, has not been thoroughly investigated. The probability of sediment mixing from multiple, differentiable source terrains typically increases with transport distance. Additionally, the likelihood and degree of mixing and fractionation may be enhanced in some depositional environments (e.g., fluvial versus marine) due to differences in sediment transport mechanisms. Cretaceous deposits along the margins of the Western Interior Seaway in North America were chosen for this study due to abundance of outcrop, core, well data from proximal-to-distal depositional environments, in conjunction with the well-established stratal relationships and depositional age constraints. We will collect samples along three proximal-to-distal transects including fluvial, shoreface, and marine shelf sandstones from strata representing a narrow time interval in the Upper Campanian. Using detrital zircon geochronology and heavy-mineral abundances, we will search for trends and systematic differences in provenance spatially and between depositional environments. This study will increase our understanding of regional sediment transport in foreland basins, provenance variability along the Western Interior Seaway, and provide insights on how to interpret detrital geochronology data.