University of Delaware
2006-2007 Distinguished Lecturer
Exploring the Application of Foraminiferal Mg/Ca Ratios to Questions of Early Cenozoic Climate Change

Much of what we know about past climate change comes from the oxygen isotopic composition of benthic foraminifera. Although this proxy outlines large-scale climate change, the absolute magnitude of glaciation and the relationship between glaciation events and ocean temperatures cannot be determined uniquely from this proxy. This is because the oxygen isotope ratios of a foraminiferal test depend on the oxygen isotopic composition of the ambient seawater and the seawater temperature. If oxygen isotope measurements are paired with an independent temperature proxy, such as foraminiferal Mg/Ca ratios, then it should be possible to constrain the temperature effect and obtain a refined view of the isotopic composition of seawater through time, which varies largely due to the growth and decay of continental ice sheets.

Mg/Ca paleothermometry, however, is limited by uncertainties related to the cycling of these cations through seawater; most studies have focused on the Pleistocene in order to avoid ambiguities related to temporal changes in seawater Mg/Ca ratios. With this in mind, I explore the application of foraminiferal Mg/Ca paleothermometry in refining the early Cenozoic history of Antarctic glaciation.

Dr. Billups participated in Ocean Drilling Program (ODP) Leg 177 (Southern Ocean Paleoceanography) as a shipboard scientist.


September 22, 2006 – University of Wisconsin-Madison
September 25, 2006 – Indiana State University
October 19, 2006 – Syracuse University
February 9, 2007 – Florida International University
February 12, 2007 – University of Miami, RSMAS
October 15, 2007 – Colorado College