Lily Claiborne

Senior Lecturer
lily.claiborne@vanderbilt.edu
Office: 6704 Science & Engineering Bldg
Phone: (615) 343-4515

Education

Ph.D. Vanderbilt University, 2011
M.S. Vanderbilt University, 2006
B.S. University of the South, 2002

Specializations

• Igneous Petrology
• Geochemistry
• Magma Chamber Processes

 

General Interests

Generally, I am interested in silicic magmatic systems, including plutonic, volcanic, and what lies in between. This includes differentiation of magmas, the fluid mechanics of crystal mushes, signatures of magmatic processes recorded in accessory minerals, assembly of plutons and sub-volcanic plumbing systems. I use fieldwork, petrography, geochronology, geothermometry, geochemistry, and theoretical and physical modeling to address magmatic questions.

I also enjoy geoscience and environmental education, whether as a Teaching Assistant or working with youth or the general public. I never miss an opportunity to share my love and my knowledge of the natural world with others, with hopes of instilling in them a better understanding and appreciation of the environment in which they live and thereby, a better awareness of their connection to and dependence and impact on the world outside themselves.

Current Research

• The sub-volcanic history of Mount St. Helens
• Composition of igneous zircon
• Physical processes in crystal mushes
• Volcano-pluton connections

Excerpt from most recent grant proposal:

Zoned zircons record the time-temperature-composition history of the magma in which they grew. Recent development of trace element analysis techniques using SHRIMP-RG (Mazdab and Wooden, 2006), combined with in situ U-Pb and U-series geochronology and the new Ti-in-zircon thermometer (Watson et al., 2006), provides a powerful tool for extracting this information. We have used this approach to delineate the complex history of the Spirit Mountain batholith in southern Nevada, including repeated episodes of crystallization, melt evolution, differentiation, recharge, and transport of magma between storage zones in the shallow, Miocene intrusive system (Lowery Claiborne, et al., 2006; Walker et al., in press). Zircons from individual samples, and even single zircon grains, record temperature variations of up to 100°C and order-of-magnitude variations in trace element concentration. Unfortunately, the timescales of closely-spaced events recorded by zoning are beyond resolution of in situ (SHRIMP) U-Pb geochronology (>105 years for Miocene zircons). By applying these methods to zircons erupted from very young volcanic systems, including U-series geochronology with its much higher age resolution (~104 years), we anticipate better constraining the timescales of pre-eruptive magmatic processes such as rejuvenation and differentiation, and providing insight concerning the connections between volcanic and plutonic systems.

While the recent history of Mount St. Helens is one of the most thoroughly investigated volcanic systems in the world, its more distant past is just beginning to be unraveled. No studies have yet attempted to read the magmatic history of the system recorded in zircons from its erupted units. The relatively low diffusivity of Zr in melts limits zircon growth and dissolution rates. Thus, analyzable zircon zones are likely to reflect relatively long-term growth (order of 103 years), and zircon grains may survive periods of undersaturation (<10 to 105 years, depending on conditions), for example in response to reheating immediately prior to eruption. This record, therefore, may provide clues as to how the magmas that erupted from Mount St. Helens were stored, differentiated, and mechanically interacted prior to eruption, both in the recent active history of the system and in less well known, earlier stages.

The dacites from Mount St. Helens, by far the most voluminous product throughout its history, appear somewhat monotonous in bulk composition, but studies of 1980-1986 and 2004-2006 mineral assemblages and phenocryst and trace-element compositions hint at a more complex history that may also be reflected in zircons from units throughout its existence. We have collected a suite of samples that span the eruptive history of Mount St. Helens, from the Ape Canyon Stage, beginning ~300 ka, to the most recent eruption (December 2005), and have extracted zircons from five samples thus far. A single analyzed sample, an Ape Canyon Stage quartz-biotite dacite, yielded a complex 238U-230Th age spectrum indicating multiple ages of growth ranging from ~50 ka to 300 ka or more. Elemental as well as U-series analyses of our samples (scheduled for May '07) will provide further insight into the evolution of the magmatic plumbing system sustaining Mount St. Helens since its beginnings ~300 ka.

Selected Publications

Claiborne, L.L., Miller, C.F., Furbish, D.J. (in prep) Teaching radioactive decay and radiometric dating:

An analog activity based on hydrostatics, Journal of Geoscience Education.

Gualda, G.A.R., Pamukcu, A.S., Claiborne, L.L., and Rivers, M.L. (2010) Quantitative 3D petrographyusing x-ray tomography. 3: Documenting accessory phases with differential absorption tomography,Geosphere, v. 6, in press [DOI:10.1130/GES00568.1]

Miller, C.F., Furbish, D.J., Walker, B.A., Claiborne, L.L., Koteas, G.C., Bleick, H.A., and Miller, J.S.(2010) Growth of plutons by incremental emplacement of sheets in crystal-rich host: evidence from Miocene intrusions of the Colorado River region, Nevada, USA, Tectonophysics, in press [DOI:10.1016/j.tecto.2009.07.011]

Claiborne, L. L., Miller, C.F., Flanagan, D.M., Clynne, M.A., Wooden, J.L. (2010) Zircon reveals protracted magma storage and recycling beneath Mount St. Helens, Geology, v. 38, no. 11, p. 1011–1014 [DOI: 10.1130/G31285.1]

Claiborne, L.L., Miller, C.F., Wooden, J.L. (2010) Trace element composition of igneous zircon: a thermal and compositional record of the accumulation and evolution of a large silicic batholith, Spirit Mountain, Nevada. Contributions to Mineralogy and Petrology, v. 160, p. 511–531 [DOI:10.1007/s00410-010-0491-5]

Lang, N.P., B.A. Walker, L.L. Claiborne, C.F. Miller, R.W. Hazlett, M.T. Heizler (2008) The Spirit Mountain batholith and Secret Pass Canyon volcanic center: A cross sectional view of the magmatic architecture of the uppermost crust of an extensional terrain, Colorado River, Nevada-Arizona. Geological Society of America Field Guide, vol. 11, p. 187-214 [DOI:10.1130/2008.fld011(09)]

Walker, B.A., C.F. Miller, L. Lowery Claiborne, J.S. Miller and J.L. Wooden (2007) Batholith construction: New insights concerning timescales and physical processes from the Spirit Mountain Batholith, southern Nevada, Journal of Volcanological and Geothermal Research v. 167, p. 239-262 [DOI:10.1016/j.jvolgeores.2006.12.008]

Claiborne, L.L., C.F. Miller, B.A. Walker, J.L. Wooden, F.K. Mazdab and F. Bea (2006) Tracking magmatic processes through Zr/Hf ratios in rocks and Hf and Ti zoning in zircons: An example from the Spirit Mountain batholith, Nevada, Mineralogical Magazine, v. 70, no. 5, p. 517-543 [DOI: 10.1180/0026461067050348]