Depositional Processes and Facies Variability in Organic-rich Mudstones of the Colorado Group, West-central, Alberta, Canada
Abstract
The Early Cenomanian to Early Turonian Fish Scales, Belle Fourche and Second White Specks formations across southern and central Alberta, comprising the lower portion of the Colorado Group, were deposited across a broad shelf setting during the Mowry Transgressive-Regressive Cycle and the transgressive portion of the Greenhorn Transgressive-Regressive Cycle. They are composed of organic-rich, mixed siliciclastic and calcareous mudstones deposited under the influence of changing paleooceanographic conditions and sediment sources within the Western Interior Seaway (WIS). Based on an understanding of sediment transport mechanisms across shelf environments, sedimentological evidence of mudstones comprising the Colorado Group suggests influences by geostrophic bottom currents. Allomembers defined within a complex stratigraphic framework of the Second White Specks Formation reveals significant lateral facies changes likely affected by subtle changes in water depth. Lastly, the spatial and temporal distribution of facies is a result of sediment reworking processes across a low gradient shelf.
Description
Keywords
Geology, Geophysics
Citation
Zajac, N. A. (2016). Depositional Processes and Facies Variability in Organic-rich Mudstones of the Colorado Group, West-central, Alberta, Canada (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/25556