The purpose of this dissertation is to track the evolution and consequences of Paleocene-Eocene thermal maximum (PETM) greenhouse gases, which is of utmost importance in determining the response of the atmosphere/ocean system to large perturbations of the global carbon cycle. The research contained within this dissertation has produced the highest resolution dataset for the PETM-onset interval to date and has refined the timing of events surrounding the short lived hyperthermal event. A high resolution (cm-scale), single-specimen stable isotope study on planktic and benthic foraminifera from the expanded carbon isotope excursion (CIE) onset interval at Site 689 (Maud Rise - Weddell Sea, high-latitude South Atlantic) concludes that the surface-ocean warmed prior to the CIE and the effects of the event progressed following a surface-to-bottom pathway. (mod. auth. abst.)