Current Research

My current research focuses on isotope geochemistry and igneous petrology, in its broadest sense. My PhD study encompasses three distinct but related projects, all of which address fundamental questions in the field of mantle geochemistry and employ the use of xenoliths. The first of which focused on the use of Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) and Electron Microprobe Analysis (EMPA) to quantify both the abundance and distribution of major and trace elements in the constituent minerals of spinel peridotite and garnet clinopyroxenite xenoliths from the suboceanic and subcratonic upper mantle. This approach has allowed us to rapidly obtain mineral-mineral partition coefficients for 32 petrogenetically important trace elements, including the period four transition metals in the natural sample. Ultimately these distribution coefficients should shed light on the controls of pressure, temperature and bulk composition on sub-solidus trace element partitioning. Secondly, a subset of these samples were analyzed for their Fe3+/Total Fe through the use of 57Fe Mossbauer spectroscopy at the Bavarian Research Institute of Experimental Geochemistry and Geophysics, University of Bayreuth in collaboration with Dr. Shantanu Keshav and Dr. Catherine McCammon. The ultimate goal of the study is to employ the measurement of ferric iron contents of lherzolite spinels and pyroxenitic garnet-clinopyroxene pairs and experimentally derived oxybarometers to quantify the oxygen fugacity of the suboceanic lithospheric mantle. Additionally, these measurements will allow for the investigation of the impact of Fe3+ contents on trace element partitioning. Finally, the third part of my dissertation research focuses on the radiogenic isotope systematics (Hf-Nd-Sr-Pb) of the rutile-bearing Koidu eclogites from Sierra Leone. These eclogites are unique in that they possess superchondritic Nb/Ta, Nb/La and Ti/Zr ratios which are imparted on the whole rock by the rutile which dominates the budget of these elements. Understanding the age (accomplished here by Lu-Hf & Sm-Nd isotope dilution mineral-mineral isochrons as well as model ages), source lithology (trace element modeling) and features of this reservoir (Hf-Nd-Sr-Pb) are key to ascertaining the role of refractory, rutile-bearing eclogite in global mantle recycling. All of this work is done at the Division of Isotope Geochemistry, National High Magnetic Field Laboratory, Florida State University and through the use of the Thermo Scientific (Finnigan) Neptune Multicollector(MC)-ICP-MS, MAT 262 Thermal Ionization Mass Spectrometer (TIMS) and Element 1 ICP-MS.

Research Interests

• Geochemistry at F.S.U.
• Mossbauer Spectroscopy at Bayreuth
• EMPA at the Florida Center for Analytical Electron Microscopy Florida International University
• Mantle Plumes
• Eclogite
• Hawaiian Volcanism
• Origins of Life
• Sea Turtle Conservation

Selected Publications

• Tibbetts, N.J.T.; Parker, W.C.; Rink, W.J. and Boyce, J.I., 2007, Observed Relationship Between Coastal Geomagnetic Anomalies and Nesting Density of Green and Loggerhead Turtles in Tortuguero, Costa Rica, Symposium on Sea Turtle Biology and Conservation, Myrtle Beach, SC, February 22-28 (2007); Published in Proceedings of the Twenty-Seventh Annual Symposium on Sea Turtle Biology and Conservation, NOAA Technical Memorandum, NMFS-SEFSC-569 64-65(talk).

Peer-Reviewed Publications

• Delano, J.W.; Zellner, N.E.B.; Barra, F.; Olson, E.; Swindle, T.D.; Tibbetts, N.J. and Whittet, D.C.B., 2007, An integrated approach to understanding Apollo 16 impact glasses: Chemistry, isotopes and shape, Meteoritics & Planetary Science, 42 (6), 993-1004.

Posters, Abstracts and Presentations

• Tibbetts, N.J.; Bizimis, M.; Salters, V.J.M. and Rudnick, R.L., 2008, The Hf-Nd Systematics of Rutile-Bearing Eclogites From Koidu, Sierra Leone, American Geophysical Union Fall Meeting, SanFrancisco, CA, December 15-19 (2008); Published in EOS Transactions of the American Geophysical Union, Fall Meeting V33C-2236, 89 (53) (2008).


• Froelich, P.N.; Kowalczk, A.J.; McCardle, D. and Tibbetts, N.J., 2007, Speleothem Paleoclimate Records from the Floridian Panhandle, American Geophysical Union Fall Meeting, SanFrancisco, CA, December 13-17 (2007); Published in EOS Transactions of the American Geophysical Union, Fall Meeting PP43A-099 8, 88 (52) (2007).


• Zellner, N.E.B.; Swindle, T.D.; Barra, F.; Delano, J.W.; Tibbetts, N.J.; Whittet, D.C.B. and Spudis, P.D., 2005, Chemical and Isotopic Analyses of Apollo 16 Glasses: An Integrated Approach, Lunar and Planetary Science XXXVI, Houston, TX, March 14-18 (2005), Abstract # 1199.

Courses Taught

Florida State University

• GLY1000 - Dynamic Earth

Research Assistant

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Community Outreach and Education

As part of the active scientific community, and especially as scientific staff at the National High Magnetic Field Laboratory, it is of utmost importance to participate in education and outreach. Through the Center for Integrating Research & Learning (CIRL) I have had many opportunities to serve as a mentor, tour guide and ombudsman between federally sponsored research scientists and the general public in many venues. Some of which have included: teaching in K-12 classrooms, presenting for the SciGirls summer camp, middle school mentorship, assisting REU and RET participants with advanced laboratory techniques and creative and interactive Open House demonstrations which reach between 3 and 5,000 people each spring.