Graduation Year


Document Type




Degree Granting Department

Marine Science

Major Professor

David Hollander, Ph.D.

Committee Member

Terrence Quinn, Ph.D.

Committee Member

Edward VanVleet, Ph.D.


geochemistry, paleoclimate, lacustrine, sedimentary, subtropical


Recent sedimentary records have indicated that climate in low latitude, continental environments have varied significantly throughout the mid to late Holocene. In subtropical North America, major climatic phenomena such as the migration of the Intertropical Convergence Zone (ITCZ) and the Bermuda High have been shown to play a major role in this variability. Specifically, the northward migration of the ITCZ and the eastward position of the Bermuda High during summer months leads to warmer and wetter conditions over subtropical North America, and vice versa. A quantitative approach to understanding hydrologic dynamics (i.e. atmospheric circulation patterns, relative humidity) associated with these and other phenomena is necessary to accurately reconstruct the behavior of these hydrologic parameters in the past. Previous studies have shown that the hydrogen isotopic composition of algal material is a direct reflection of source waters, and that hydrogen isotopic enrichment in terrestrial material relative to aquatic biomass is a function of evaporative processes associated with the level of relative humidity in a given environment. This study utilizes a lacustrine system to provide a modern calibration that will attempt to develop a new climatic proxy for relative humidity and further examine varability in the behavior of environmental waters. This calibration was then applied to a sedimentary record to examine hydrologic variability in the geologic past.