Publication Date

Summer 2019

Advisor(s) - Committee Chair

Michael T. May (DIrector), Patricia Kambesis, Fredrick D. Siewers

Degree Program

Department of Geography and Geology

Degree Type

Master of Science

Abstract

The Ste. Genevieve Limestone is a Mississippian-aged, carbonate-dominated stratigraphic unit that is a prominent hydrocarbon producer in the Illinois Basin, and is widely distributed in states such as Missouri, Kentucky, Indiana, and Illinois. There has been relatively limited study focused on characterizing the Ste. Genevieve Limestone in terms of lithofacies, stacking patterns, and sequence stratigraphic context via analysis of roadcut exposures of the unit in western Kentucky.

The focus of this study is to use lithologic data collected from roadcuts and draft these data into cross sections for presentation of detailed stratigraphic columns that are locally correlative. Seven roadcuts were used in the study, five in Warren County Kentucky and two in Barren County Kentucky. The goal of this study is to characterize the lithofacies, stacking patterns, and sequence stratigraphy of the Ste. Genevieve Limestone. Another goal is to identify intervals in the unit that have a high potential to be hydrocarbon reservoirs and by extension, determine associated rocks that may function as seals or traps for reservoirs.

The results of this study show that the characteristics of the Ste. Genevieve Limestone in western Kentucky are:

  • Roadcut consists of three stratigraphically distinct stacking patterns: 1) alternating coarse-grained units and fine-grained units, 2) a backstepping, retrogradational,shoal-building pattern, and 3) static, thick coarse-grained intervals.
  • The roadcuts are dominated by limestone units, with coarse intervals consisting of mainly skeletal-ooid grainstones and fine-grained intervals representative of mudstones and wackestones.
  • Dolomitized limestone is present, with dolomitized mudstone making up the majority of dolomitic units and fine-grain units in general.
  • Oolitic and skeletal units are the most ideal hydrocarbon reservoir rocks in the roadcuts with paleokarst intervals such as brecciated limestone also being viable potential reservoirs.
  • The presence of thick skeletal and skeletal-ooid grainstones are indicative of High Stand System Tracts (HSTs), which make up the majority of roadcut exposures and brecciated limestone in contrast, is indicative of a Falling Stage System Tract (FSST).
  • Overall, the rocks exposed in the roadcuts are representative of shoal or shoaling upward environments yet possess localized partitioning of units based on identification of depositional and diagenetic facies changes.

Disciplines

Geology | Oil, Gas, and Energy | Sedimentology | Stratigraphy

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