Geochemical record of subduction

Geochemical record of subduction

Author: PNAS August 3, 2026 Duration: 10:35

Evidence of early plate tectonics

Science Sessions are brief conversations with cutting-edge researchers, National Academy members, and policymakers as they discuss topics relevant to today's scientific community. Learn the behind-the-scenes story of work published in the Proceedings of the National Academy of Sciences (PNAS), plus a broad range of scientific news about discoveries that affect the world around us.

In this episode, Brad Peters explores what we can learn from the journey of sediments from the early Earth through the rock cycle.

In this episode, we cover:
•[00:00] Introduction.
•[01:04] Geochemist Brad Peters tells us about the Marquesas Archipelago and why is it a place of interest for geologists.
•[02:42] He recounts evidence suggesting that one component of the Marquesas lavas was recycled sediment from the early Earth.
•[04:59] Peters walks us through the likely journey of this sediment from its origins to its eruption on the Marquesas Archipelago.
•[06:24] He explains what this lava tells us about the tectonic processes that were active four billion years ago.
•[07:43] Peters summarizes how this result is different than what we previously thought about the inception of plate tectonics.
•[08:19] He talks about what the results mean for the story of the early Earth.
•[09:13] He lists the caveats and limitations of the study.
•[10:09] Conclusion.

About Our Guest:

Brad Peters
Postdoctoral researcher
ETH Zurich

View related content here: https://www.pnas.org/doi/abs/10.1073/pnas.2500506123

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Tune into PNAS Science Sessions for a direct line to the people shaping modern science. Produced by PNAS, this podcast offers more than just summaries of published research; it’s where you hear the candid, often personal stories behind the headlines. Each episode features concise conversations with the researchers themselves-from emerging voices to established Academy members-alongside the policymakers whose decisions are informed by this work. You’ll get a genuine sense of the questions that drive these experts, the unexpected hurdles they face in their labs and field studies, and why their findings matter right now. The scope is deliberately wide, reflecting the interdisciplinary nature of science itself, covering discoveries that range from microscopic processes to planetary-scale phenomena. This isn't about dry lectures, but about capturing the human endeavor of investigation. For anyone curious about how science actually unfolds and wants to understand the context of breakthroughs as they happen, this podcast serves as an essential, engaging resource. It connects the dots between a published paper in a prestigious journal and the real-world implications that ripple out from it.
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