Kristeen McGonigal Roessig

---

Paleontology

Current Research:

Ocean Drilling Program Leg 189 drilled 4 high quality sites south of Tasmania in order to eludicate paleoceanographic conditions prior to and following the opening of the Tasmanian Seaway. My research will focus on the changes in nannofossil assemblages through the Miocene epoch. In particular, I will
1) Correlate late Oligocene to early Miocene nannofossil marker species in the Southern Ocean with high-resolution oxygen-isotope stratigraphy from the same samples. Other microfossil groups (dinocysts, benthic foraminifera, and planktonic foraminifera) will also be available for correlation. Only one study of deep-sea sediments has correlated nannofossil bioevents with the Mi events (Maiorano and Monechi, 1998).
2) Test the paleobiogeographic interpretations for Miocene calcareous nannofossils (Haq, 1980) in the Southwest Pacific. Statistical analysis and comparison between sites will provide paleoenvironmental information for genera not considered in Haq's study (1980), such as Calcidiscus and Cyclocargolithus .
3) Determine if the glacial events described by Zachos, et al. (1997) can be identified at Leg 189 sites by fluctuations in calcareous nannofossils assemblages. To record how the nannofossil assemblages change across the Oi and Mi events in terms of species diversity, nannofossil size, species turnover, nannofossil absolute abundance, and nannofossil flux.
4) Calculate if fluctuations in the nannofossil populations display Milankovitch cyclicity. Oxygen-isotope variations, carbonate variations, magnetic susceptibility and other sedimentological parameters have been shown to fluctuate at Milankovitch cyclicities through this time interval (Zachos, et al., 1997; Paul, et al., 2000; Abdul Aziz, 2000). Nannofossil fluctuations in the late Miocene (Beaufort and Aubry, 1990) and the early Jurassic (Walsworth-Bell, Bown, and Weedon, 2000) have demonstrated cyclicity at Milankovitch periods.

Research Interests:

Micropaleontology
Ocean Drilling Program, Leg 189: Southern Gateways
Stable isotope geochemistry

Professional Information:

• M.S. Geology, 2000, Florida State University (FSU)
• B.S. Geology, 1993. University of California, Davis (UCD)
• Member of International Nannoplankton Association (INA)
• Curriculum Vitae (CV)

Advisor: Sherwood Wise