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I study how Earth's crust and mantle evolve over time using a variety of quantitative geochemical and geochronologic techniques. My research interests include ancient mantle domains, radiogenic heating in the crust, continental collision zones, and geobiological feedbacks.

Contact me if you are interested in research opportunities or collaboration. I am enthusiastic about working with scientists at all levels!

News and Highlights


Our paper in Nature reports the highest magmatic 3He/4He yet found in terrestrial rocks. Find out why we think that helium in Baffin Island lavas and elsewhere might be coming from Earth's core.

Are high 3He/4He ratios in intraplate lavas derived from solar nebula preserved in Earth's core?

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We are assessing helium isotope variability in recent volcanic eruptions to determine whether helium might inform volcanic hazard forecasts. See this Oceanus article for details.

In collaboration with Pete Barry and Marc-Antoine Longpré

Can helium isotopes in lavas inform volcanic hazard forecasts?


From a single rock, we recovered a nearly complete record of Himalaya-type continental collision

See our paper in Journal of Metamorphic Geology about this incredible sample from Madagascar.

Deeply subducted seafloor sediments of the Indus Fan melted, ascended as magmas, and erupted in southern Afghanistan. 

See my paper in Nature Geoscience about the discovery of the first subduction zone carbonatite volcano. Seafloor sediments that are carbon-rich can subduct into Earth's mantle and then return to the surface to form volcanoes formed primarily of carbonate minerals. See Nature Reviews Earth & Environment for a research highlight.

We discovered primordial neon in Baffin Island lavas!

See our recent publication in Earth and Planetary Science Letters.

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Carbonatites are rare igneous rocks composed primarily of carbonate minerals. Our recent paper about a carbonatite volcano in Afghanistan highlights the important role of fluids during carbonatite volcanism...

See our recent publication in Geochemistry, Geophysics, Geosystems.

See our paper about helium in olivine

"Helium distributions in ocean island basalt olivines revealed by X-ray computed tomography and single-grain crushing experiments" - Horton, Farley, and Jackson

We discovered that helium and CO2 are hosted in fluid inclusions inside olivine crystals. Carbon escapes as grains decrepitate (crack due to a buildup of overpressure in the inclusions) as they ascend in hotspot lavas. Helium probably diffuses through the olivine lattice.


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Successful 2018 field season on Baffin Island!

Paul Asimow, Joe Biasi, and I had an adventurous field season in the Arctic Circle in August, 2018. We explored the high 3He/4He lavas that erupted as Greenland and Canada rifted apart. These rocks potentially hold clues about the deepest, oldest domains in Earth's mantle.


Click here to learn more about this research.


Department of Geology & Geophysics

Woods Hole Oceanographic Institution

360 Woods Hole Rd, MS #08
Woods Hole, MA 02543 USA


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