TONIGHT: The Earth's First Crust

Richard Carlson

Thursday, September 24, 2020 - 18:30
Neighborhood Lecture Series
Richard Carlson, Director, Earth & Planets Laboratory

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Earth is unique amongst the rocky planets in having two very different types of crust. Continental crust is composed primarily of silica-rich rocks like the granite of your kitchen countertops. Oceanic crust is instead almost entirely a black magnesium and iron-rich volcanic rock, basalt, like that erupted in Hawaii.

The continental crust juts above water because it is thick and granite is less dense than basalt so it floats higher on top of Earth’s interior. Oceanic crust sinks back into Earth’s interior on hundred-million-year timescales. In contrast, the buoyancy of continental crust allows it to survive longer at Earth’s surface. Even so, only a very small portion of Earth’s surface consists of rocks formed within half a billion years of Earth formation.

EPL Director Richard Carlson will discuss the continuing efforts to find these rare remnants of Earth’s oldest crust and what they can tell us about what our home planet was like in its infancy.

The lecture will be held via Zoom and will be streamed live on the EPL YouTube channel.

About NLS: 

After postponing our lectures this spring, we're thrilled to announce that the Neighborhood Lecture Series is back—virtually of course. The silver lining? Now that the lectures are being held online, the whole world is our neighborhood!

As always our Neighborhood Lectures provide an opportunity to explore the world from the perspective of scientists who are working at the leading edge of scientific discovery. The lectures will begin at 6:30 p.m. EST and last for approximately one hour, followed by a brief question and answer period. Please note that registration will be required to access the Zoom webinar. We will also be streaming to our YouTube channel.