Geology Bites: An Earth and Planetary Science Podcast

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Roberta Rudnick on the Continental Crustal Composition Paradox

Continental crust is derived from magmas that come from the mantle. So, naively, one might expect it to mirror the composition of the mantle. But our measurements indicate that it does not. Continental crust contains significantly more silica and less magnesium and iron than the mantle. How can we be sure this discrepancy is real, and what do we think explains it? In the podcast, Roberta Rudnick presents our current thinking about these questions. Surprisingly, more than 30 years after she and others first identified the so-called continental crustal composition paradox, there is still no consensus among geologists as to which of the many proposed hypotheses most convincingly solves the paradox. Rudnick is a Distinguished Professor in the Department of Earth Science at the University of California Santa Barbara. Illustrations and full transcript: https://geologybites.com/roberta-rudnick

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  Tony Watts on the Mechanics of Tectonic Plates

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  Torgeir Andersen on Ultrahigh-Pressure Metamorphism

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  Brian Wernicke on Lithospheric Extension and the Basin and Range Province

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  Bernhard Steinberger on Whether Hotspots Are Fixed

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  Sonia Tikoo on the Moon's Magnetic Field

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  Steve Brusatte on the Dinosaurs That Survived the Asteroid

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  Alec Brenner on When Tectonic Plates First Moved

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  Steve Jacobsen on Materials in Extreme Environments

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  Esther Sumner on Turbidity Currents

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  Hal Levison on the Mission to Jupiter's Trojan Asteroids

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  Sara Pruss on the First Reef Builders

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  Michael Manga on Wet Eruptions

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  Carina Hoorn on the Evolution of the Amazon Basin

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  Anat Shahar on What Makes a Planet Habitable

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  Keith Klepeis on How Plutons Form

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  Tom Herring on High-Precision Geodesy