CWU geology graduate students receive GSA Graduate Student Research Grants
Congratulations to Rachel Hunt, Matt Jenkins, Aaron Mayfield, and Sarah Nagorsen, whose Geological Society of America Graduate Student research proposals were funded. The GSA research grants program provides support of MS and PhD research. In 2010, 51% of graduate student applicants received funding.
Rachel's research will focus on testing two different hypotheses for the origin of compositional diversity observed on Alicudi Island, Italy. In one model (Bonelli et al., 2004) the basalts and basaltic andesites were dominated by assimilation (A)-fractional crystallization (FC) processes in deep magma reservoirs. Andesites evolved in a shallow chamber by FC. In the other model (Peccerillo et al., 2004) both sets of eruptive products evolved in deep magma reservoirs, and basalts and basaltic andesites experienced assimilation during ascent because they were hotter. Each model predicts distinct and testable core to rim compositional changes in plagioclase. To test these hypothesese, Rachel will determine these compositional changes by probing plagioclase using the electron microprobe and Laser Ablation Multi Collector Inductively Coupled Mass Spectrometry (LA-MC-ICPMS).
Aaron's research will focus on the Fossa delle Felci flow sequences, Salina Island, Italy. He will apply magma chamber models MELTS (Ghiorso & Sack, 1995) and Energy-Constrained Assimilation-Fractional Crystallization (EC-AFC) (Spera & Bohrson, 2001) to quantify the differentiation history of these flows. Modeling will produce concrete predictions of compositional changes as recorded in plagioclase that grew as a ubiquitous phase in the Fossa delle Felci magma. Plagioclase growth records and retains a record of local magma chamber conditions. Core to rim textural and in situ analysis of plagioclase in the sequence will elucidate changing magma chamber conditions, thereby directly testing model predictions and evaluating the efficacy of the quantitative models.
Matt will process and analyze an ice core recovered from the Tibetan Plateau for concentrations of black carbon,
the second largest contributor to global warming behind CO2.
When deposited on snow and ice, black carbon reduces albedo and enhances energy absorption, and is thought to be the main contributor to a recent warming of twice the global mean in the region. However, there are no records of black carbon from the Tibetan Plateau spanning pre-industrial time to present, essential information for evaluating black carbon’s role in recent climate change, and its contributions to early snow melt and glacier retreat in the source region of many of Asia’s largest rivers. Matt's research will establish the first historical record of regional black carbon concentrations from the Tibetan Plateau through high-resolution analysis of the ice core, and will help to further our understanding of black carbon's role in climate change.
Sarah's research will test two hypotheses: (a) extensional and strike-slip deformation rates increased within ~50 km east of the Sierra Nevada, CA as a consequence of the initiation of uplift of that mountain range at 5-3 Ma (Jones et al., 2004) and (b) 0.4-0.8 mm/yr of dextral fault slip is predicted to have been transferred since the Pliocenen northward into the Adobe Hills, CA region (Lee et al., 2009). To test these postulates, Sarah will complete (U-Th)/He geochronology on magnetite, a powerful new geochronologic tool for dating mafic extrusive volcanic rocks, from basalt lavas and cones exposed in the Adobe Hills. Sarah's mapping in the Adobe Hills shows that deformation is characterized by ENE-striking sinistral faults that curve into or cut NS-NNW-striking normal faults. Both fault sets cut and offset basalt lavas, but not basalt cinder cones. Measured offset linear and planar features yield a minimum sinistral offset of 2.1 ± 0.1 km across the Adobe Hills. If the Adobe Hills basalt lava flows are Pliocene in age, then net sinistral slip rates range from ~0.4-1.0 mm/yr, a result consistent with both hypotheses.