whoover [at] umd [dot] edu

Sarah Penniston-Dorland

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Natural hazards, such as earthquakes and volcanoes, profoundly impact human life, yet the mechanisms that drive these events are still poorly understand, in part because such geologically short events (<<1 million years) are difficult to identify in the geologic record. I integrate diffusion chronometry, stable isotope geochemistry, petrology and field geology to constrain the short duration and high spatial-resolution record of fluid and melt transport in Earth’s crust and mantle and its role in driving natural hazards.

My PhD research has focused on fluid flow in subduction zones and its relationship to earthquakes. Currently, I am using bulk and in situ Li isotope measurements and diffusion chronometry to identify rapid, cyclic fluid flow events which are invoked by many models of subduction zone seismicity. This research is part of a large multi-disciplinary international research network studying subduction processes (http://geoprisms.org/exterra/e-fire).

In addition to these geologic questions, I am interested in the development of new methods for in situ measurement of non-traditional stable isotopes. As part of my PhD, I have developed a method for the analysis of Li isotopes in garnet by secondary ion mass spectrometry.

In addition to my geologic research, I am involved in a number of STEM and earth science education and outreach efforts in the local community. I am the Program Manager for Kids Excelling in Math and Science, an after school science enrichment program at Hyattsville Middle School (find out more at http://kemsmaryland.org). I have also organized several K-8 field trip programs that use hands-on activities to teach about the rock cycle, mineral and rock identification and the layers of the earth. If you are interested in a field trip feel free to shoot me an email!

Barnes, J., Penniston-Dorland, S., Bebout, G., Hoover, W., Beaudoin, G., Agard, P. (2019) Chlorine and lithium behavior in metasedimentary rocks during prograde metamorphism: A comparative study of exhumed subduction complexes (Catalina Schist and Schistes Lustrés). Lithos. 336-337 40-53. DOI: 10.1016/j.lithos.2019.03.028

Hoover, W., Page, F.Z., Schulze, D., Kitajima, K., Valley, J. (2020) Massive fluid influx beneath the Colorado Plateau (USA) related to slab removal and diatreme emplacement: Evidence from oxygen isotope zoning in eclogite xenoliths. Journal of Petrology. 61 DOI: 10.1093/petrology/egaa102

Hoover, W.F., Penniston-Dorland, S.C., Baumgartner, L.P., Bouvier, A.-S., Baker, D., Dragovic, B., Gion, A. (2021) A method for SIMS analysis of lithium isotopes in garnet: The utility of glass reference materials. Geostandards and Geoanalytical Research. 45(3) 477-499. DOI: 10.1111/ggr.12383

Hoover, W.F., Penniston-Dorland, S.C., Baumgartner, L., Bouvier, A.-S., Dragovic, B., Locatelli, M., Angiboust, S., Agard, P. (2022) Episodic fluid flow in an eclogite-facies shear zone: Insights from Li isotope zoning in garnet. Geology. 50 (6) 746-750. DOI: 10.1130/G49737.1

Hoover, W.F., Penniston-Dorland, S.C., Piccoli, P.M., Kylander-Clark, A. (2023) Reaction-Induced Porosity in an Eclogite-Facies Vein Selvage (Monviso Ophiolite, W. Alps): Textural Evidence and In Situ Trace Elements and Sr Isotopes in Apatite. Journal of Petrology. 64 1-23. DOI: 10.1093/petrology/egac128