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Geology Bites

89 episodes - English - Latest episode: about 1 month ago -

What moves the continents, creates mountains, swallows up the sea floor, makes volcanoes erupt, triggers earthquakes, and imprints ancient climates into the rocks? Oliver Strimpel, a former astrophysicist and museum director asks leading researchers to divulge what they have discovered and how they did it.

To learn more about the series, and see images that support the podcasts, go to geologybites.com.
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Twitter: @geology_bites
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Episodes

Damian Nance on What Drives the Supercontinent Cycle

February 24, 2024 14:47 - 35 minutes - 26.1 MB

Perhaps as many as five times over the course of Earth history, most of the continents gathered together to form a supercontinent. The supercontinents lasted on the order of a hundred million years before breaking apart and dispersing the continents. For decades, we theorized that this cycle of amalgamation and breakup was caused by near-surface tectonic processes such as subduction that swallowed the oceans between the continents and upper mantle convection that triggered the rifting that s...

David Kohlstedt on Simulating the Mantle in the Lab

February 09, 2024 14:25 - 32 minutes - 21.1 MB

The Earth’s tectonic plates float on top of the ductile portion of the Earth’s mantle called the asthenosphere. The properties of the asthenosphere, in particular its viscosity, are thought to play a key role in determining how plates move, subduct, and how melt is produced and accumulates. We would like to know what the viscosity of the the asthenosphere is, and how it depends on temperature, pressure, and the proportion of melt and water it contains. Few mantle rocks ever reach the Earth’s...

Claire Corkhill on Geological Radioactive Waste Disposal

January 07, 2024 16:10 - 31 minutes - 18.7 MB

In many countries, nuclear power is a significant part of the energy mix being planned as part of the drive to achieve net-zero greenhouse-gas emissions. This means that we will be producing a lot more radioactive waste, some of it with half-lives that approach geological timescales, which are orders of magnitude greater than timescales associated with human civilizations. In the podcast, Claire Corkhill discusses the geology such storage sites require, some new materials that can confine ra...

Mahesh Anand on What Human Return to the Moon Means for Lunar Geology

December 22, 2023 18:23 - 32 minutes - 24.5 MB

We have learned a great deal about the geology of the Moon from remote sensing instruments aboard lunar orbiters, from robot landers, from the Apollo landings, and from samples returned to the Earth by Apollo and robot landings. But in 2025, when NASA plans to land humans on the Moon for the first time since 1972, a new phase of lunar exploration is expected to begin. What will this mean for our understanding of the origin, evolution, and present structure of the Moon? A lot, according to Ma...

Susan Brantley on Earth's Geological Thermostat

December 10, 2023 20:35 - 27 minutes - 21 MB

At the core of Earth’s geological thermostat is the dissolution of silicate minerals in the presence of atmospheric carbon dioxide and liquid water. But at large scales, the effectiveness and temperature sensitivity of this reaction depends on geomorphological, climatic, and tectonic factors that vary greatly from place to place. As described in the podcast, to predict watershed-scale or global temperature sensitivity, Susan Brantley characterizes these factors using the standard formula for...

Clark Johnson on the Banded Iron Formations

November 12, 2023 19:48 - 28 minutes - 21.1 MB

Banded Iron Formations (BIFs) are a visually striking group of sedimentary rocks that are iron rich and almost exclusively deposited in the Precambrian. Their existence points to a major marine iron cycle that does not operate today. Several theories have been proposed to explain how the BIFs formed. While they all involve the precipitation of ferric (Fe3+) iron hydroxides from the seawater via oxidation of dissolved ferrous (Fe2+) iron that was abundant when the oceans contained very low le...

Catherine Mottram on Dating Rock Deformation

October 18, 2023 23:55 - 36 minutes - 25 MB

The geological history of most regions is shaped by a whole range of processes that occur at temperatures ranging from above 800°C to as low as 100°C. The timing of events occurring over a particular temperature range can be recorded by a mineral which crystallizes over that range. The mineral calcite is suitable for recording low-temperature processes such as fossilization, sedimentation, and fluid flow, and it is especially useful as it is virtually ubiquitous. But using uranium-lead radi...

Martin Van Kranendonk on the Earliest Life on Earth

September 12, 2023 18:50 - 33 minutes - 24.9 MB

In this episode, Martin Van Kranendonk lays out a convincing case for life on Earth going back to at least 3.48 billion years ago. To find evidence for very ancient life, we need to look at rocks that have been largely undisturbed over billions of years of Earth history. Such rocks have been found in the Pilbara region of northwest Australia. As explained in the podcast, the 3.48-billion-year-old (Ga) rocks of the Pilbara's Dresser Formation contain exceptionally well-preserved features tha...

Rob Butler on the Origin of the Alps

August 17, 2023 13:56 - 30 minutes - 22.3 MB

The Alps are the most intensively studied of all mountain chains, being readily accessed from the geological research centers of Europe. But despite this, there remains considerable uncertainty as to how they formed, especially in the Eocene (about 40 million years ago) when the events that led directly to Alpine mountain-building started. In the podcast, Rob Butler explains how much of this uncertainty stems from our fragmentary knowledge of the locations and structures of sedimentary basin...

John Wakabayashi on the Franciscan Complex

July 03, 2023 18:41 - 32 minutes - 23.7 MB

The Franciscan Complex is a large accretionary prism that has been accreted onto the western margin of the North American continent. Unlike most such prisms, which are submarine, it is exposed on land, making it a magnet for researchers such as John Wakabayashi. In the podcast, he describes this remarkable complex and explains the mechanisms that may have operated over its 150-million-year history. John Wakabayashi is a Professor in the Department of Earth and Environmental Sciences at Cali...

Bruce Levell on Bias in the Sedimentary Record

June 20, 2023 19:47 - 33 minutes - 23.6 MB

How can we tell if the sedimentary record is good enough to make solid inferences about the geological past? After all, it can be difficult, or even impossible, to infer what is missing, or indeed whether anything is missing at all. As he explains in the podcast, Bruce Levell tackles this question by combining fieldwork with systematic analysis based on what we know about contemporary deposition and erosion. Armed with an understanding of preservational bias, he questions the confidence wit...

Sujoy Mukhopadhyay on Probing the Hadean World with Noble Gases

April 20, 2023 23:25 - 33 minutes - 23.5 MB

In a recent episode, Nadja Drabon spoke about newly discovered zircon crystals that formed during the late Hadean and early Archean, when the Earth was between 500 million and a billion years old.  The zircons revealed information about processes occurring in the Earth’s nascent crust, casting light on when and how modern-day plate tectonics may have started.  In this episode, we talk about a very different source of information about the early Earth, namely the abundances of noble gases occ...

Patrick Fulton on the 2011 Tōhoku Earthquake

March 23, 2023 11:33 - 30 minutes - 22.5 MB

In 2011, a massive earthquake struck off the eastern coast of Japan. The destructive power of the earthquake was amplified by a giant tsunami that swept ashore, killing over 15,000 people. A major cause of the tsunami was the 50-m slip along the plate boundary fault between the subducting Pacific plate and the overriding North American plate. Patrick Fulton and his team set out to find out why there was so much movement along the fault by installing a temperature observatory in a borehole d...

Romain Jolivet on the 2023 Turkey-Syria Earthquakes

March 02, 2023 00:23 - 29 minutes - 20.5 MB

Romain Jolivet studies active faults and the relative motion of tectonic plates.  His research focuses on the relationship between slow, aseismic slip that occurs “silently” between earthquakes and the rapid slip accompanying earthquakes.  As he describes in the podcast, he uses interferometric synthetic aperture radar (InSAR) images from radar satellites to examine surface deformation over wide areas at meter-scale resolution.  InSAR images of the 2023 Turkey-Syria earthquakes reveal compli...

Dan Rothman on Thresholds of Catastrophe in the Earth System

February 10, 2023 14:36 - 37 minutes - 26 MB

The geological record shows that the Earth’s carbon cycle suffered over 30 major disruptions during the Phanerozoic.  Some of the biggest ones were accompanied by mass extinctions.  Dan Rothman analyzed these disruptions to find a pattern governing their magnitude and duration.  As he explains in the podcast, this pattern is suggestive of a non-linear dynamical system that, once excited, undergoes a large excursion before returning to where it was.  Could we be exciting such a disruption now...

Nadja Drabon on a New Lens into the Hadean Eon

January 02, 2023 01:02 - 26 minutes - 17.7 MB

Vanishingly few traces of the early Earth are known, so when a new source of zircon crystals of Hadean age is discovered, it makes a big difference to what we can infer about that eon.  In the podcast, Nadja Drabon describes how she analyzed the new zircons she and her colleagues discovered and what they reveal about the Earth’s crust between about 4 and 3.6 billion years ago. Nadja Drabon is Assistant Professor of Earth and Planetary Sciences at Harvard University. For podcast illustrations...

John Cottle on the Petrochronology Revolution

December 03, 2022 20:53 - 29 minutes - 22.1 MB

Over the course of Earth history, many parts of the crust have undergone multiple episodes of metamorphism.  Modern methods of dating and measuring trace-element abundances are now able to tease out the timing and conditions of the individual episodes.  But new techniques were needed before these methods could be scaled up to unravel regional tectonic events such as the formation of mountain belts and subduction zones and continental rifting.  In the podcast, John Cottle describes one such t...

Martin Gibling on Rivers in the Geological Record - Part 2

November 10, 2022 19:18 - 25 minutes - 18.4 MB

This episode is the second of two of my conversation with Martin Gibling.  In the first episode, we discuss fluvial deposits in the geological record and we trace the effect that the break-up of Pangea around 200 million years ago had on river systems.  In this episode, we address the history of the rivers of Europe and the Americas, as well as the impact of the recent ice ages on today’s rivers.  We end by considering how humans have changed rivers and their deposits throughout mankind’s hi...

Martin Gibling on Rivers in the Geological Record - Part 1

November 10, 2022 19:11 - 29 minutes - 21.7 MB

Rivers can seem very ephemeral, often changing course or drying up entirely.  Yet some rivers have persisted for tens or even hundreds of millions of years, even testifying to the breakup of Pangea, the most recent supercontinent, about 200 million years ago.  On the one hand, their courses may be determined by tectonic processes such as the formation of mountain belts.  And on the other, they themselves can affect tectonic processes by creating continent-scale features, such as giant submar...

Anna Fleming on the Experience of Rock Climbing

October 10, 2022 11:04 - 18 minutes - 13.5 MB

This episode is a bit of a departure from the objective approach to geology of past episodes in that here we address the subjective nature of various rocks as experienced by a rock climber with a literary bent. A rock climber’s very survival can depend on the properties of a rock encountered along a climbing route.  This engenders a uniquely intense relationship between climber and rock.  Anna Fleming has written perceptively about this intense relationship gained from climbing in Britain a...

Brian Upton on the Unique Rift Zone of South Greenland

September 02, 2022 23:10 - 26 minutes - 17.3 MB

Between 1.3 and 1.1 billion years ago, magma from the Earth's mantle intruded into a continent during the assembly of the supercontinent called Nuna. Through good fortune, the dykes and central complexes that resulted have been preserved in near-pristine condition in what is now the south of Greenland. The dykes are extraordinarily thick, and the central complexes contain an order of magnitude more exotic minerals than otherwise similar complexes around the world. In the podcast, Brian Upton...

Geoff Abers on Subduction Zones and the Geological Water Cycle

August 10, 2022 20:50 - 27 minutes - 23.4 MB

Subduction zones are places where a slab of oceanic lithosphere plunges into the mantle below.  The slab consists of the sediments on top, crustal rocks in the middle, and the lithospheric mantle on the bottom, all plunging down together as a kind of sandwich.  In each of these layers is an ingredient that plays a key role in shaping the evolution of the Earth over geological time – and that is water. Geoff Abers has conducted extensive research on water in subduction zones.  In this episod...

Maria McNamara on Seeing the Ancient World in Color

June 17, 2022 08:03 - 30 minutes - 20.6 MB

Popular reconstructions of ancient environments, whether they be in natural history museum dioramas, in movies, or in books, present a world of color. But are those colors just fanciful renderings, perhaps based on the colors we see around us today?  Or is there evidence in the fossil record that we can use to determine the actual color of plants and animals that lived in the geological past? Maria McNamara tries to answer these questions by studying the fossil preservation of soft tissues,...

Phil Renforth on Carbon Sequestration

June 01, 2022 17:45 - 25 minutes - 18.3 MB

For many years, efforts to limit climate change have focused on curtailing anthropogenic emissions of greenhouse gases.  But it is increasingly clear that such curtailment will not, on its own, be able to prevent the damaging effects of global warming.  Therefore, more attention is now directed to mitigating climate change by enhancing the removal or sequestration of greenhouse gases from the atmosphere.  As a result, our climate change goals are now often specified in terms of when we plan ...

Tony Watts on Seamounts and the Strength of the Lithosphere

May 12, 2022 12:45 - 28 minutes - 20.3 MB

When plate tectonics was adopted in the 1960s and early '70s, researchers quickly mapped out plate movements.  It seemed that plates moved as rigid caps about a pole on the Earth's surface.  But since then, a lot of evidence has accumulated suggesting that plates are not, in fact, totally rigid.  In fact, we can see them flex in response to stresses that are imposed on them.  Such stresses can arise on plate boundaries, such as when two plates collide and one plate flexes down to subduct und...

Neil Davies on the Greening of the Continents

April 24, 2022 22:28 - 33 minutes - 26.9 MB

Life only emerged from water in the Ordovician.  By that time, life had been thriving in oceans and lakes for billions of years.  What did the colonization of the land look like, and how did it reshape the Earth’s surface?  Neil Davies describes how we can decipher the stratigraphic sedimentary record to address these questions.  Perhaps surprisingly, it’s easier to recognize small and fleeting events than to recognize large-scale features such as mountains, valleys, and floodplains.  He als...

Ben Weiss on the Mission to the Mission to Psyche

April 12, 2022 22:23 - 30 minutes - 19.3 MB

The asteroid Psyche is probably the most metal-rich body we have discovered.  There are two, quite different, theories as to how it may have formed: Either it formed that way, or it originally had a more typical composition, but its rocky outer portion was blasted off during a major collision.  To help determine which is most likely, NASA is sending a space probe there, to be launched on August 1, 2022.  And if we can unravel the history of Psyche, we will also learn how other planets may ha...

Ben Weiss on the Mission to Psyche

April 12, 2022 22:23 - 30 minutes - 19.3 MB

The asteroid Psyche is probably the most metal-rich body we have discovered.  There are two, quite different, theories as to how it may have formed: Either it formed that way, or it originally had a more typical composition, but its rocky outer portion was blasted off during a major collision.  To help determine which is most likely, NASA is sending a space probe there, to be launched on August 1, 2022.  And if we can unravel the history of Psyche, we will also learn how other planets may ha...

Roger Bilham on Himalayan Earthquakes

March 22, 2022 18:03 - 34 minutes - 25.5 MB

We hear about earthquakes in the Himalaya, especially when they claim lives and cause damage. And we understand that, broadly speaking, it is the continued northward movement of India ploughing into Tibet that causes these earthquakes. But where exactly do the earthquakes occur, how do they occur, and what determines how much damage they inflict? Roger Bilham has conducted a detailed study of the historical record of earthquakes in the Himalaya over the past millennium. He tries to reconcil...

Susannah Porter on Tiny Vampires in Ancient Seas

March 01, 2022 22:11 - 34 minutes - 23.6 MB

The fossil record of complex life goes back far beyond the Cambrian explosion, to as far back as 1,600 million years ago in the late Paleoproterozoic with the first appearance of eukaryotes.  But these creatures only started to diversify much later, around 750 million years ago.  What enabled this evolutionary change has been a puzzle, but one idea is that it reflects the appearance of microscopic predators.  In the podcast, Susannah Porter tells us how she discovered incontrovertible signs ...

Ana Ferreira on Seeing Flows in the Mantle

February 21, 2022 21:53 - 22 minutes - 17.8 MB

Does the pull of a subducting slab drive plate motions?  Or is it the upwellings of convection cells in the mantle?  We now have a new way to shed light on this question.  It's called seismic anisotropy, which is the spreading out of seismic waves according to their direction of polarization.  This happens when the mantle through which the waves travel has crystals which are preferentially aligned, and that occurs when there is deformation or flow going on.  So we can work backwards to use t...

Phil Gibbard on the Anthropocene

February 12, 2022 20:51 - 27 minutes - 19.8 MB

There’s a lot of debate about the idea that the global changes brought about by humans define a new geological epoch, dubbed the Anthropocene. Should such an epoch be added to the official geological time scale? If so, what aspect or aspects of anthropogenic change should be used, and exactly where do we place the golden spike that will define the base of the Anthropocene? Such questions come under the purview of the International Commission on Stratigraphy, whose current secretary general ...

David Bercovici on How Plate Subduction Starts

February 05, 2022 18:35 - 30 minutes - 21.6 MB

Subduction zones are a fundamental aspect of plate tectonics, yet we still don't really understand how subduction initiates.  It's a tough problem because as oceanic plates move away from a mid-ocean spreading center and cool, they get stiffer and should become more and more resistant to bending and sinking down into the mantle.  But recent work suggests that the clue to this puzzle lies in the physics of grains at the microscale.   David Bercovici is one of the geologists who has pioneered...

Bob Hazen on the Evolution of Minerals

January 25, 2022 20:11 - 34 minutes - 26.6 MB

New rock types emerge during the history of the Earth.  For example, the silica-rich felsic rocks such as granite that characterize continental crust, accumulated during the course of Earth history.  Granite only forms in certain specific tectonic settings, such as above subduction zones and when lower crustal rocks melt in mountain belts.  But what about the minerals themselves?  Have they been around since the Earth formed, or did they too only appear on the scene later as a result of some...

Matt Jackson on the Heterogeneity of the Mantle

January 08, 2022 17:03 - 35 minutes - 26.2 MB

Matt Jackson is a Professor of Earth Science at the University of California, Santa Barbara.  He probes the chemical composition of the mantle by analyzing trace elements and isotopes in hot-spot lavas from around the world.  In the podcast, he describes the intriguing heterogeneity among the hot-spots of the so-called “hot-spot highway” in the western Pacific.  The heterogeneity there, as well as on larger spatial scales is challenging our ideas about the motions of the mantle over the billi...

Carmie Garzione on Reconstructing Land Elevation Over Geological Time

January 01, 2022 15:43 - 31 minutes - 24.3 MB

Throughout geological history, various points on the Earth’s surface have been lifted up to great elevations and worn down into low, flat-lying regions.  Determining surface elevation histories is difficult because rocks that were once on the surface are usually eroded away or buried.  Furthermore, most rock-forming processes are not directly affected by elevation.  But it turns out that we can overcome these challenges, as Carmie Garzione explains in the podcast.  Carmie Garzione is Dean o...

Chuck DeMets on High-Resolution Plate Motions

December 25, 2021 14:57 - 34 minutes - 24.7 MB

The magnetic stripes frozen into the sea floor as it forms at mid-ocean ridges record the Earth’s magnetic field at the time of formation.  Reversals in the Earth’s magnetic field define the edges of these stripes, in effect time-stamping the sea floor position. Chuck DeMets is Emeritus Professor of Geoscience at the University of Wisconsin, Madison.  He studies the magnetic anomalies in seafloor rocks to reconstruct plate motions at a temporal resolution five times better than has been don...

Mike Searle on Ophiolite

December 18, 2021 03:07 - 28 minutes - 20.5 MB

As the name implies, oceanic lithosphere underlies the oceans of the world.  Except when they are ophiolites, when oceanic lithosphere is thrust on top of a continental margin.  Are ophiolites a special kind of oceanic lithosphere?  Or are there peculiar tectonic circumstances that emplace denser oceanic rocks on top of lighter continental ones?  Mike Searle addresses these questions, and reveals the sequence of events that created the world's most extensive and best-preserved ophiolite - th...

Mackenzie Day on Dunes

December 11, 2021 17:02 - 24 minutes - 18.5 MB

Some of the most extensive sandstone deposits in the world were deposited by wind.  How do such aeolian rocks differ from water or ice-deposited rocks?  And  what do they reveal about the environments in which they formed?  In the podcast she describes the dunes we see in the geological record on Earth, as well as on Mars and on a comet, and explains what we've learned from them. Mackenzie Day is an Assistant Professor in the Department of Earth, Planetary, & Space Sciences at the Universit...

Sue Smrekar on the VERITAS Mission to Venus

December 04, 2021 16:10 - 34 minutes - 26.4 MB

The best maps we have of Venus were made by Magellan, a space probe that flew in the 1990s.  In the summer of 2021, NASA approved a new mapping mission that will produce radically improved maps of the topography, radar reflectivity, and gravity field, and the first ever global map of surface rock type.  Sue Smrekar, the mission Principal Investigator, explains why this will revolutionize our understanding of Venus and perhaps also throw light on the early history of Earth when processes anal...

Rick Carlson on Probing the Early Solar System

November 28, 2021 17:09 - 33 minutes - 35.5 MB

Almost all the evidence about the nascent solar system has been erased by processes accompanying the formation of the Sun and the bodies that formed out of the circumsolar disk about 4.6 billion years ago.  But some meteorites and the tiny dust grains contained within them have anomalous compositions that can only be understood by invoking a history going back to the giant molecular cloud progenitor of the solar system, and to the stars that ejected the material that formed the cloud.  Rick ...

Ed Marshall on Iceland's 2021 Eruption

November 13, 2021 23:07 - 27 minutes - 20.7 MB

After months of high earthquake activity, a fissure opened up near the southwestern tip of Iceland on March 19, 2021. Over a period of about seven months, several other fissures opened up, generating lava flows several kilometers long that filled several valleys and created a new 150-meter high mountain, a sort of mini-shield volcano. The eruption has been intensively studied by geologists because it is the first eruption of its kind in Iceland in living memory, and also because it’s extreme...

Richard Fortey on the Trilobite Chronometer

November 07, 2021 00:55 - 25 minutes - 17.3 MB

Long before radiometric dating appeared on the scene, the geological time scale was defined by the sedimentary record, and particularly by key fossils preserved within them.  Throughout the Cambrian, and to a lesser extent until the end-Permian extinction about 300 million years later, trilobite fossils served as some of the most useful of these key fossils.  Richard Fortey explains why.  Here he is holding a trilobite from the calymene genus. Richard Fortey is formerly head of arthropod pa...

Paul Hoffman on the Snowball Earth Hypothesis

November 01, 2021 14:57 - 32 minutes - 32.3 MB

We’re all familiar with the idea of ice ages during which the polar ice caps advance to cover significant portions of their respective hemispheres, and then, after a period of tens to hundreds of thousands of years, retreat back to the polar regions.  But now we believe that twice during the Earth’s history, the ice advanced all the way to the equator, almost completely blanketing the Earth with a sheet of ice several kilometers thick.  This is the Snowball Earth hypothesis.  In the podcast ...

Peter Cawood on When Plate Tectonics Started

October 23, 2021 16:32 - 30 minutes - 22.6 MB

The heat liberated during the formation of our planet created an ocean of magma.  As it began to cool, the Earth differentiated into a dense metallic core surrounded by a less dense rocky mantle.  At some point, we know that the surface of the Earth must have formed itself into the rigid blocks we call plates, and that these plates began to move and interact with each other as parts of the global process we call plate tectonics.  But did the plates form and did plate tectonics start soon aft...

Becky Flowers on Deciphering the Thermal History of Rocks

October 16, 2021 22:33 - 30 minutes - 22 MB

Many processes in geology affect the temperature of rocks.  Erosion is one example — as a surface is eroded, the rocks below get closer to the surface, cooling as they go.  So if we know the temperature history of a rock, we can infer its erosion history.  Becky Flowers has a thermochronology lab in which she determines the cooling history of rocks as recorded in specific crystals they contain, such as zircon and apatite.  She explains how this works, and how she has used her results to unra...

Ulf Linnemann on the Assembly of Central Europe in the Paleozoic

October 09, 2021 03:08 - 25 minutes - 18.9 MB

The geological history of Central Europe is quite complicated.  The region is composed of several continental blocks having quite distinct origins that came together over 300 million years ago in the Paleozoic Era.  Then, in the Mesozoic, many of the original rocks were overlaid, and continued plate movements caused mountain belts to form.  In a previous Geology Bites podcast, Douwe van Hinsbergen explained how he used an analysis of the geological structure of mountain belts to reconstruct ...

Douwe van Hinsbergen on What Drives the Motions of Tectonic Plates

September 18, 2021 22:59 - 26 minutes - 17.4 MB

Ever since Alfred Wegener proposed the theory of continental drift in 1912, we have been aware that blocks of the Earth’s lithosphere are moving with respect to each other.  With the advent of plate tectonics in the 1960s, these moving blocks became identified with the tectonic plates that tile the Earth’s surface.  We now have accurate measurements of plate motion speeds, which range from about ½ a cm per year to 10 cm per year.  But there is still no general consensus as to what makes plat...

Mathilde Cannat on Mid-Ocean Ridges

August 19, 2021 13:53 - 29 minutes - 20.9 MB

Oceanic plates are continually manufactured at mid-ocean spreading ridges.  But exactly what processes go on at these ridges?  It turns out that it depends on what type of ridge it is—fast-spreading or slow-spreading.  And that our traditional view of vanishingly thin plate thickness at ridge axes is inaccurate.  Mathilde Cannat describes our modern understanding of mid-ocean ridges and the observations that led us there. Mathilde Cannat is a research director at the Institut de Physique du G...

Kathryn Goodenough on the Sources of Lithium for a Post-Carbon Society

August 09, 2021 13:59 - 19 minutes - 14.1 MB

The lithium-ion battery was invented about 40 years ago, and is now commonplace in a range of products, from smartphones to electric cars. But if we are to meet the carbon emission goals that governments are setting, electrification, and with it the need for electricity storage, will increase dramatically. Although many new electricity storage methods are being developed, none are as mature as the lithium-ion battery, which will therefore need to be a major part of a carbon-free infrastructu...