Electronic Theses and Dissertations

Date of Award

1-1-2025

Document Type

Dissertation

Degree Name

Ph.D. in Engineering Science

First Advisor

Jennifer N. Gifford

Second Advisor

Brian F. Platt

Third Advisor

Lance D. Yarbrough

School

University of Mississippi

Relational Format

dissertation/thesis

Abstract

Southeast Laurentia has many Cretaceous-aged suites of alkalic volcanics with unknown origins and lack geochemical data. The primary goal of the research is to define the origins of Cretaceous-aged volcanism and volcanic materials in and around the Mississippi Embayment (MSE) through geochemical analyses via fusion inductively coupled plasma mass spectroscopy (F-ICP-MS). The MSE is within the Mississippi Valley Graben (MVG), an area of significant intraplate seismic activity and volcanism throughout geologic history. Throughout the MSE and surrounding region are suites of ultramafic and alkalic intrusive complexes and associated volcanic suites from the Cretaceous (~145–66 Ma), these suites include peridotite, lamprophyre, kimberlite, syenite, and carbonatite. Geochemical (Major/Trace/REE) and petrologic analyses performed indicate deep mantle origins (≥150 km) for samples within a linear trend of volcanic provinces, providing context for hotspot volcanism being the mode of formation. The secondary goal is to compare data to modern examples of hotspot volcanism to identify possible congruence in volcanic province formation via a case study in the Canary Islands. Data from the Canary Islands does aid in identifying hotspot REE signals within the MSE. Finally, the research aims to identify the origins of volcaniclastic gravels found in the Pleistocene (~2.85–0.012 Ma) aged PLTDs of western MS. The volcaniclastics show geochemical correlation with the in situ volcanics of the St. Francois Mountains of Missouri. This indicates glacial advance further into the southern US than previously accounted within the literature.

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