So much of what we make starts with materials we extract from the Earth.   Some of these materials make up only a tiny proportion of our planet, but fortunately for us, they are concentrated in certain places, which makes it possible to extract them in economically viable quantities.   So how exactly do these materials become concentrated?

Lawrence Robb is a Visiting Professor at the Department of Earth Sciences at Oxford University.   By analyzing the relationship between mineral deposits, principally in Africa and Asia, and our latest understanding of plate tectonics and mountain-building, he has unraveled the processes that formed some of our most important mineral deposits.

Go to geologybites.com for illustrations that support this episode as well as to learn more about the podcast series.

Bruce Buffett is a Professor in the Department of Earth and Planetary Science at the University of California, Berkeley.   He investigates the structure and motions within the Earth’s core by matching physics-based simulations of the core to the observed magnetic field of the Earth.

Go to geologybites.com for diagrams that support this podcast episode as well as more about the Geology Bites podcast series.

David Sandwell uses satellites to make accurate measurements of the shape of the ocean surface.  He explains how this enabled him to create a global map of the topography on the sea-floor.  This revealed the global extent of classic plate-tectonic features, such as spreading ridges and transform faults, but also intriguing new features we still do not understand.

David Sandwell is a Professor at Scripps Institution of Oceanography at the University of California San Diego.

Barbara Romanowicz uses the seismic waves triggered by earthquakes to probe the interior of the Earth.  She has forged new techniques for analyzing these waves to give us a much sharper view of the deep structure of the Earth.  She is a Professor of the Graduate School at the University of California at Berkeley, and Chair of Physics of the Earth’s Interior at the Collège de France in Paris.

The Earth was formed just over 4.5 billion years ago.  What happened just after it formed and what were conditions like then?  John Valley reveals what we have managed to discover about our planet’s very distant past, and how we did it.

The asteroid belt lies between the orbits of Mars and Jupiter.   It formed out of the same protoplanetary disc as the Earth, but many asteroids have barely changed since then.  Sara Russell explains what these time capsules can reveal about the Earth and how we will learn much more from the spacecraft currently fetching and returning asteroid samples to Earth.

Sara Russell is a professor of planetary sciences and leader of the Planetary Materials Group at the Natural History Museum in London.  Her research seeks to unravel how the solar system formed and cast light on questions such as how the Earth got its water and organic materials.  She even has an asteroid named after her.

Most rocks were formed many millions of years ago.  Since then, some have been largely left alone, while others have been baked at high temperatures and buried at great depths.  Clare Warren explains how we can now uncover remarkably precise histories of such rocks, even if they have been through more than one episode of such extreme treatment.

Clare Warren is a Senior Lecturer in the School of Environment, Earth and Ecosystem Sciences at The Open University.

For more on Geology Bites, go to geologybites.com, where you can also find diagrams and pictures that support the podcast.

Why do some volcanoes erupt almost all the time but others lie dormant for centuries, millennia, or even longer?  Steve Sparks has turned our ideas about volcanoes upside down.  Not quite literally, but by applying the physics of fluid motion to the rocks and magma below volcanoes, he discovered that magma forms at much greater depths than previously thought, eventually forming an unstable blob that forces its way up through as much as a hundred kilometres of overlying rocks to erupt from a volcano.  It is how quickly such blobs form that determines how frequently a volcano will erupt. 

For more on Geology Bites, go to geologybites.com, where you can also find diagrams and pictures that support the podcast.

Steve Sparks has turned our ideas about volcanoes upside down.  Not quite literally, but by applying the physics of fluid motion to the rocks and magma below volcanoes, he discovered that magma forms slowly at much greater depths than previously thought, eventually forming an unstable blob that forces its way up through the overlying rocks to erupt from a volcano. 

Why look to another planet to reveal something new about the Earth?  Dan McKenzie describes an ingenious way of using the data sent back from the Magellan Venus orbiter to discover that Venus is covered with an elastic plate about 30 kilometers thick.   Explaining this very unexpected result revealed something extraordinary about the Earth.

For more on Geology Bites, go to geologybites.com, where you can also find diagrams and pictures that support the podcast.