Date of Award
6-2018
Degree Name
Master of Science
Department
Geological and Environmental Sciences
First Advisor
Dr. Stephen E. Kaczmarek
Second Advisor
Dr. William B. Harrison III
Third Advisor
Dr. Peter Voice
Fourth Advisor
Jay Zambito
Keywords
A-1 carbonate, chemostratigraphy, Michigan Basin, ED-XRF, sequence stratigraphy
Access Setting
Masters Thesis-Open Access
Abstract
Handheld energy dispersive x-ray fluorescence spectrometry (ED-XRF) is routinely used to observe elemental variability in fine-grained siliciclastics but has been applied rarely in fine-grained carbonates. Here, ED-XRF chemostratigraphy is utilized in the texturally homogenous, mudstones of the Silurian A-1 Carbonate (A-1C), Michigan Basin. Previous studies on the A-1C focused on the stratigraphic relationship with the underlying Niagaran reefs, so little is known about the geological variability in the basin center. In this study, high-resolution elemental data from nine cores were integrated with petrographic and mineralogical observations to evaluate two hypotheses: (1) Texturally homogeneous, basin-center mudstones in the A-1C have spatially correlative elemental signatures (i.e. chemofacies); (2) Elemental variations reflect temporal changes in relative sea-level, redox conditions, and sedimentation rate.
Spatially correlative temporal variations in Si, Al, K, and S are observed between basin-center wells. High abundances of Si, Al, and K associated with siliciclastic minerals are interpreted to reflect intensification of clastic sedimentation during low sea-level. Associated S increases are interpreted as diagenetically altered gypsum that was deposited during periods of low sea-level. Chemofacies successions indicate 6 low-order transgressive-regressive cycles and up to 14 high-order cycles. These findings demonstrate the ability of ED-XRF to provide geologically relevant elemental data that can be used to refine sequence stratigraphic interpretations in fine-grained carbonates.
Recommended Citation
Hemenway, Matthew A., "Application of Handheld ED-XRF for High-Resolution Chemostratigraphy in Texturally Homogeneous Carbonate Mudstones: Salina A-1 Carbonate (Silurian), Michigan Basin" (2018). Masters Theses. 3704.
https://scholarworks.wmich.edu/masters_theses/3704