Master of Science (MS)
Geology and Geophysics
The Eocene-Oligocene (E-O) transition is a key interval in geological history because it marks a major change in Earth’s climate and because these strata are also popular oil targets in the Gulf Coast. E-O sequences in Alabama are stratigraphically complex. The St. Stephens Quarry (SSQ) in Alabama is one of the few accessible quarries along the Gulf Coast where the E-O boundary is visible in outcrop. Despite the abundance of research projects conducted in the SSQ, many controversies still surround the E-O boundary placement and correlation to the Global Stratotype in the Massignano section in Italy that is based on the extinction of the Hantkeninidae family. The lack of Hantkenina sp. (Miller et. al., 2008) in a core from near the SSQ and the stratigraphy there contribute to the controversy in boundary placement. To supplement the rarity of foraminifera biomarkers in the section, I present the results of a high-resolution palynological study of the St. Stephens Quarry in Alabama, to help better constrain the boundary placement and associated environmental changes. The new data provide 1) an alternate biostratigraphic zonation and locate the E-O boundary based on organic-walled microfossils to increase biostratigraphic control in the Gulf Coast region, 2) a way to supplement and assist biosteering when foraminifera are not present, and 3) new environmental data (sea-surface conditions and climate) across the boundary. By comparing SSQs palynomorph assemblages to worldwide stratigraphic charts we have established that the E-O boundary occurs within the transition between the Shubuta marl and the Bumpnose limestone (between 3.60- 3.65m depth).
Document Availability at the Time of Submission
Release the entire work immediately for access worldwide.
Jensen, Kevin, "A high-resolution palynological analysis of the St. Stephens Quarry, Alabama: locating the Eocene-Oligocene boundary and characterizing the environmental changes across the margin" (2012). LSU Master's Theses. 3330.