People | Katharina Billups

• B.S., Geology, University of California, Davis, 1991.
• M.S., Geology, University of California, Davis, 1993.
• Ph.D., Earth Sciences, University of California, Santa Cruz, 1998.

I use light stable isotopes and other geochemical tools to investigate paleoclimates and ocean history as recorded in deep-sea sediments. My research primarily involves the application of stable isotopes in planktonic and benthic foraminifera to extract paleoenvironmental information about the surface and deep ocean. The stable isotopic composition of foraminifera is a fundamental tool to reconstruct individual components of the earth's climate system, such as surface and deep ocean circulation, from which we learn about past ocean-atmosphere interactions and climate sensitivity to boundary conditions, for example. I am interested in the processes behind the climate record which necessitates comparisons of proxies on millennial to tectonic time scales. This research is anchored in large volumes of stable isotope analyses on relatively small samples. I have a facility for stable isotope mass spectrometry.

At sites in the northwestern subtropical North Atlantic we are generating multi-species, high resolution, planktonic and benthic foraminiferal stable isotope records that span the time interval between about 1.4 Ma to 0.3 Ma. This time period includes many glacial to interglacial cycles as climate evolved toward more extreme states. Our objective is to investigate the relative climate stability of glacial versus interglacial periods.

We are constructing benthic and planktic foraminiferal stable isotope records from ODP Site 1208 in the northwestern subtropical Pacific spanning the early to late Pliocene climate transition. We are interested in the role of the subtropical Pacific surface ocean in the development of wide spread Northern Hemisphere Glaciation at this time.

Together with collaborators in Europe (L. Diester-Haas, K. Emeis, L. Francois) I am reconstructing marine productivity over key intervals of the Neogene. The project involves proxies (benthic foraminiferal accumulation rates and geochemical records) as well as numerical modeling to better understand the relationship between the carbon cycle and longer term climate change. 

Nicholas Venti, Ph.D. Student

Nicole Voutsina, Undergraduate Student, University of Delaware

Jessie Wenke, Undergraduate Student, Department of Geology, University of Delaware

• Geological Oceanography MAST 637
• Paleoceanography MAST/GEOL 857
• Isotope Geochemistry MAST 852

2008

Weirauch, D. K. Billups and P. Martin.  2008.  Evolution of Millennial-Scale Climate Variability During the Mid Pleistocene, Paleoceanography, 23, PA3216, doi:10.1029/2007PA001584.

Billups, K., C. Kelly and E. Pierce.  2008. The Late Miocene to Early Pliocene Climate Transition in the Southern Ocean, /Palaeoecology, Palaeogeography, Palaeoclimatology, 267, 31-40.

Billups, K. 2008. A Tale of Two Climates, Nature Geosciences, 1, 294-295.

Lazarus, D., B. Bittniok, L.  Diester-Haass, K. Billups,  Y. Ogaway, Y. Takahashi, K. Takahashi and P. Meyer. 2008. Radiolarian and sedimentologic paleoproductivity proxies in late Pleistocene sediments of the Benguela Upwelling System, ODP Site 1084, Marine Micropaleontology, 68, 223-235.

Waite, A., L. Diester-Haass, S. Gibbs, R. Rickaby, H. Stoll and K. Billups. 2008.  A Top-down and Bottom-up Comparison of paleoproductivity proxies: Calcareous Nannofossil Sr/Ca Ratios and Benthic Foraminiferal Accumulation Rates, G-Cubed, 9, doi: 10/1029/2007GC001812. **

2007

Billups, K. and K. Scheiderich.  A synthesis of late Oligocene through Miocene deep sea temperatures as inferred from foraminiferal Mg/Ca rations.  Sedimentology, in press.

Ravelo, A.C., K. Billups, P.S. Dekens, T.D. Herbert and K.T. Lawrence.  2007. Onto the Ice Ages:  Proxy evidence for the onset of Northern Hemisphere Glaciation, in deep-time perspectives on climate change:  marrying the signal from computer models and biological proxies.  M. Williams, A.M. Haywood, J. Gregory and D. Schmidt (eds).  The Geological Society of London and the Micropalaeontological Society. 

2006

Diester-Haass, L., K. Billups and K. C. Emeis. The late Miocene carbon isotope shift and marine biological productivity in the Indo-Pacific Ocean (ODP Sites 721, 1172, 1146, and 846): a (dusty) link? Paleoceanography/, 21, doi.:10.1029/2006PA001267,2006.

Billups, K., C. Lindley, J. Fisler and P. Martin. 2006. Mid Pleistocene climate instability in the subtropical northwestern Atlantic. Global Planetary Change, 54, 251-262.

Lazarus, D., Bittniock, B., Meyers, P., Diester-Haass, L. and K. Billups. 2006. Comparison of radiolarian and sedimentologic Paleoproductivity proxies in the latest Miocene-Recent Benguela Upwelling System. /Marine Micropaleontology, 60, 269-294.*

Billups, K., C. Lindley, J. Fisler and P. Martin. 2006. Mid Pleistocene climate stability in the subtropical northwestern Atlantic, Global Planetary Change, 54, Issues 3-4, 251-262.

2005

Diester-Haass, L., K. Billups and K.C. Emeis. 2005. In search of the late Miocene-early Pliocene "Biogenic Bloom" in the Atlantic Ocean, (ODP Sites 982, 925, 1088). Paleoceanography, 20:10.1029/2005PA001139.

Niemitz, M. D. and K. Billups. 2005. Millennial-scale variability in western tropical Atlantic surface ocean hydrography during the early Pliocene. Marine Micropaleontol. 54:155-166.

Billups, K. 2005. A snowmaker for the ice ages. Nature News and Views. 433:809-810.

2004

Billups, K., R. Rickaby and D. P. Schrag. 2004. Cenozoic pelagic Sr/Ca records: Exploring a link to paleoproductivity. Paleoceanography, 19: doi: 10.1029/2004PA 001011.

Billups, K., H. Paelike, J. Channell, J. Zachos and N. Shackleton. 2004. Astronomic Calibration of the Late Oligocene Through Early Miocene Geomagnetic Polarity Time Scale. EPSL, 224:33-44

Billups, K., W. Chaisson, M. Worsnopp and R. Thunell. 2004. Millennial-Scale Fluctuations in Subtropical Northwestern Atlantic Surface Ocean Thermal Stratification. Paleoceanography, 19: doi: 10.1029/2003PA000990.

Rosenthal, Y., S. Perron-Cashman, C. H. Lear, E. Baard, S. Barker, K. Billups, M. Bryan, M. L. Delaney, P. B. deMenocal, G. S. Dwyer, H. Elderfield, C. R. German, M. Greaves, D. W. Lea, T. M. Machiotto, D. K. Pak, A. C. Ravelo, G. L. Paradis, A. D. Russell, R. R. Schneider, K. Scheiderich, L. Stott, K. Tachikawa, E. Tapa, R. Thunell, M. Wara, S. Weldeab and P. A. Wilson.  2004.  Inter-laboratory comparison study of Mg/Ca and Sr/Ca, measurements in planktonic foraminifera for paleoceanographic research.Geochemistry, Geophysics, Geosystems, 5: (4), 10.1029/2003GC000650.

Billups, K.  2004. Low-down on a rhythmic high. Nature (News and Views), 427:686-687.

2003

Billups, K. and D. P. Schrag.  2003.  Application of benthic foraminiferal Mg/Ca ratios to questions of early Cenozoic climate change. Earth and Planetary Science Letters, 209:181-195.

Channell, J.E.T., S. Galeotti, E.E. Martin, K. Billups, H. Scher and J.S. Stoner.  2003.  Eocene to Miocene magnetic, bio-and chemostratigraphy at ODP Site 1090 (subantarctic South Atlantic). Geological Society of America Bulletin, 115:607-623.

2002

Billups, K.  2002.  Late Miocene through early Pliocene deep water circulation and climate change viewed from the subantarctic Southern Ocean. Palaeoecology, Palaeogeography, Palaeoclimatology, 185:287-307.

Billups, K., J. Channell and J. Zachos.  2002.  Late Oligocene to Early Miocene Geochronology and Paleoceanography From the Subantarctic South Atlantic. Paleoceanography, 17:(1), 10.1029/2000PA000568.
Billups, K. and D. P. Schrag. 2002.  Paleotemperatures and Ice-Volume of the Past 27 myr Revisited with Paired Mg/Ca and Stable Isotope Measurements on Benthic Foraminifera. Paleoceanography, 17:(1), 10.1029/2000PA000567.

Lindley, Carolyn. Millennial-scale variability during the Pleistocene: An investigation of climate stability during marine isotope stages 12-16 (M.S., 2004). Office of Climate Observation, NOAA.

Scheiderich, Kathleen. Multiple uses for paried Mg/Ca and oxygen isotope measurements of foraminiferal calcite: Paleoclimatic, Paleoceanographic, and Tectonic applications. (M.S., 2004). University of Maryland, College Park (Ph.D. Student).

Waite, Amanda Jo. Top down and bottom up: A comparision of nannofossil SR/CA and benthic foraminiferal accumulation rates as paleoproductivity indicators. (M.S., 2005). Rosenstiel School of Marine & Atmospheric Science, Miami, FL (Ph.D. Student).

Weirauch, Daniel. A high-resolution record of climate instability spanning ~1.0 million years across the mid-Pleistocene transition. (M.S., 2007).