Ask a Geologist:Plumes and Plates

By: Val Finlayson

© Johan Swanepoel

About MeVal Finlayson● Most of the time: Isotope geochemist! Also:

cyclist, tinkerer (coding, paint, things that move), occasional musician

● PhD 2017, U. of Hawai’i-Mānoa, currently a postdoc researcher at U. of Maryland

● Favorite volcanoes: Lōihi, Arago Seamount

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(PHOTO OF YOU)

Plates

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Source: globalchange.umich.edu

● “Plates” of crustal rock on Earth’s surface

● Continents, ocean basins

Plates

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Source: globalchange.umich.edu

● “Plates” of crustal rock on Earth’s surface

● Continents, ocean basins

Plates

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Brown et al. (2015)

Most volcanoes are at plate boundaries. What about these “intraplate ones?

Plumes

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Hand et al. (2015)

Plumes

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Hand et al. (2015)Koppers et al. (2001)

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Plates, plumes, and time

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Finlayson et al. (submitted)

● Plume chemistry tells us about what’s deep inside the Earth

Plates, plumes, and time

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Finlayson et al. (submitted)

Konrad et al. (2018)

● And comparing plumes to each other tells us how things change deep in the Earth

“Seeing” Earth’s interior

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● Seismics “see” hot/dense (red) and cold (blue) structures in the mantle

● These circulate the mantle, driving plates AND plumes!

Why Do We Care?A few reasons!1. Knowing plate tectonics helps us know more about

earthquakes and volcanoes2. Understanding how plumes work over time3. Looking for metals, resources that form in some

volcanic systems4. How do (habitable) planets work?

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Deeper looks in time, planets

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USGS

Bernhard Steinberger

Deeper looks in time, planets

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USGS

Bernhard Steinberger

What’s nextUnderstanding what we see at the surface of a planet helps us “see” its interior better

Understanding how the Earth formed and changed with time, how it became able to support life

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© Johan Swanepoel

Question Time!