Date of Award
1-1-2024
Document Type
Dissertation
Degree Name
Ph.D. in Engineering Science
First Advisor
Brian Platt
Second Advisor
Jennifer Gifford
Third Advisor
Lance Yarbrough
School
University of Mississippi
Relational Format
dissertation/thesis
Abstract
This study was carried out to characterize the sequence stratigraphic framework, sand and sandstone diagenesis, and inorganic geochemistry of the Upper Cretaceous Tuscaloosa Group in the southern-central Mississippi Embayment. Sequence stratigraphic analysis revealed nine systems tracts: three each of lowstand (LSTs), transgressive (TSTs), and highstand (HSTs) systems tracts. LSTs show progradational and aggradational stacking patterns of fluvial and incised valley settings. TSTs comprise mainly mud with some sandstone and siltstone originating in deltaic and distal shelf environments, displaying retrogradational stacking patterns. HSTs consist mostly of sandstone with mudrocks and siltstones of deltaic and proximal shelf settings, showing progradational and aggradational stacking patterns. The formation of Tuscaloosa sequences was primarily controlled by accommodation space, influenced by global sea-level rise and the Mississippi Embayment subsidence, and sediment supply from the Appalachians, with the Ouachita highlands serving as a secondary source.
Tuscaloosa sands and sandstones exhibit various diagenetic features, including clay, carbonate, and hematite cements, grain dissolution, and evidence of mechanical compaction. Compaction has a more significant impact on porosity reduction than cementation, with average compactional porosity loss (COPL) values of 23.0% compared to mean cementational porosity loss (CEPL) values of 7.7%. Based on cement content, intergranular porosity, and compaction porosity loss values, nine diagenetic facies were identified. The study revealed that Spontaneous Potential (SP) logs were effective in distinguishing only three of these diagenetic facies and showed limitations in differentiating between compaction and cementation-influenced diagenetic facies.
Four chemofacies in sandstones and five in mudrocks + carbonate chemofacies were identified through a combination of geochemical and statistical analyses. In sandstone chemofacies, Si, Si/Al, and Si/Ca ratios positively correlate with permeability, while Al, K, Rb, Sr, Fe, and Mg show negative correlations. In mudrocks + carbonates, Ca and Si/Al ratio positively correlate with permeability, while Fe, K, S, Zn, and Rb show inverse correlations. The Lower Tuscaloosa shows high Ca values in some intervals, indicating carbonate cementation under oxidizing conditions. The Middle Tuscaloosa exhibits evidence of anoxic conditions with increasing S and Fe concentrations. The Upper Tuscaloosa displays fluctuations in Zr and Nb, suggesting potential compositional variations in the sediment source area.
Recommended Citation
Zubi, Husamaldeen, "Sequence Stratigraphy, Diagenesis, and Inorganic Geochemistry of The Tuscaloosa Group in the South-Central Mississippi Embayment" (2024). Electronic Theses and Dissertations. 2991.
https://egrove.olemiss.edu/etd/2991