George Kemper's Honours Thesis Abstract

Thesis Title: 
Sedimentology of the Outan Island Formation

The Hele Member of the Outan Island Formation, Sibley Group, is dominantly composed of fine-grained sediments, most commonly mudstone/siltstone to fine-grained sandstone.  Sedimentary structures consist of parallel lamination, soft sediment deformation features, in the form of load structures, and cross-stratified sandstone featuring a distinct lack of desiccation cracks, vegetation and evaporite formation.
The frequency of small-form ripples and parallel laminations in fine-grained sediment were taken to be representative of a low-energy system with a high suspended load.  The abundant load structures are indicative of frequent, flashing addition of sediment to a wet substrate.  The lack of desiccation cracks and evaporites indicate a non-arid environment ranging into the sub-humid.  Ancient, sub-humid dryland fluvial systems are sparsely researched and comparisons were instead drawn to modern dryland systems and ancient dryland systems, omitting or compensating for factors such as aridity conditions (formation of caliche and evaporites) and bioturbation (ruining the preservation of depositional structures.)

The Hele Member is theorized to be representative of an inland, basinal, sub-aerial, low-gradient, ephemeal, semi-humid, ancient, fluvial floodplain dominated environment based on the outcome of this study and data from Rogala, 2003.