Sedimentology of the basal Stoddart Formation (Upper Mississippian) in the area of Josephine Field, northwest Alberta

Abstract

<p> A sedimentogical and petrological examination of the basal sands of the Stoddart Formation in the area of Josephine field has been undertaken. The determination of the depositiianal environment and the history of sedimentation of the basal Stoddart sands are the objectives of this study. </p> <p>The thick sands at the base of the Stoddart Formation which have a blocky gamma ray response consist of fine-grained sandstone dominated by angle of repose cross-bedding. The sedimentary structures, stratification types, composition and facies relationships of these sands indicate that they are of a coastal aeolian origin.</p> <p>The compositional, textural and surface texture characteristics of these sands were studied under petrographic, cathodolumenescent and scanning electron microscopes. Observations indicate that the above criteria can be used to support the interpretation of an aeolian origin for the cross-bedded sands of the basal Stoddart Formation. </p> <p>The sands of the basal Stoddart show rapid transitions between sub-aerial and marine environments. These rapid changes are believed to be caused by sudden sea level fluctuations resulting from movement of reactivated faults in the Peace River arch area. </p>