Geology Bites: An Earth and Planetary Science Podcast

Latest Episodes:

Mathilde Cannat on Mid-Ocean Ridges Aug 19, 2021

Show notes

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 Globe of Paris. Her research on mid-ocean ridges has fundamentally changed our understanding of the geological processes that create new oceanic crust at these ridges. For podcast illustrations and more about Geology Bites, go to geologybites.com.

Kathryn Goodenough on the Sources of Lithium for a Post-Carbon Society Aug 09, 2021

Show notes

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 infrastructure.

Kathryn Goodenough is Principal Geologist at the British Geological Survey. She studies the geology of critical raw materials, and particularly of lithium. She is the Principal Investigator for the Lithium for Future Technology, an international consortium that investigates all types of lithium deposits and how they can be extracted sustainably.

For podcast illustrations and more about Geology Bites, go to geologybites.com.

Steve D'Hondt on Reviving a 100-Million-Year-Old Bacterial Colony Jul 28, 2021

Show notes

The fossil record goes back through the Phanerozoic eon, about 540 million years, and even earlier, into the Ediacaran period. But while the fossils provide incontrovertible evidence of ancient life, the fossils themselves are certainly not alive. In fossils, the original organic matter belonging to the fossilized life form has been replaced by inorganic materials, cast into the shape formerly occupied by the life form. However, in some situations, the original organic matter does survive. For example, original spores as old as 350 million years have been identified using their original organic material. And DNA can survive for as much as a million years. But in 2019, bacteria that had been buried 100 million years with barely any access to nutrients were not only identified but shown to be alive. Had they been in suspended animation for all that time? Or were they managing to eke out a living using much less energy than was previously thought to be necessary?

Steve D’Hondt is a Professor of Oceanography at the University of Rhode Island. He studies life beneath the sea floor and was on the team that discovered bacterial cells living in 100 million-year-old sediment.

To see podcast illustrations and learn more about Geology Bites, go to geologybites.com.

Harriet Lau on the Motions of the Earth on Timescales from Hours to Millennia Jun 12, 2021

Show notes

The subfield of geology called geodynamics most commonly refers to the motions associated with convection in the mantle. These are slow by human standards and lead to phenomena such as plate motions, seafloor spreading, mountain building, and volcanos. But the Earth’s interior actually undergoes motion on a whole range of timescales. The shortest of these occurs within seismic waves – in which the vibrations triggered by earthquakes cause tiny elastic movements of the material as they pass through. And the longest of these are the large-scale viscous motions of the convecting mantle driven by the temperature difference between the bottom and the top of the mantle. But there are a whole range of intermediate timescale motions lasting, hours, days, years, and millennia.

Harriet Lau is an Assistant Professor in Department of Earth and Planetary Sciences at the University of California at Berkeley. In this episode the describes the motions of the solid Earth that take place over these intermediate timescales and explains what they can reveal about the Earth’s interior.

For podcast illustrations and to learn more about Geology Bites, go to geologybites.com. Follow Geology Bites on Twitter @geology_bites, @oliverstrimpel, and on Instagram oliverstrimpel.

Craig Jones on the Iconic Landscapes of the American Westerns Jun 03, 2021

Show notes

Many hundreds of films have been shot on location in the American West. The rugged, inhospitable landscapes are an integral part of what gives so many American Westerns their distinctive character. Although the region is vast, stretching from the Rockies in Wyoming and Colorado to Utah, New Mexico, Nevada, Arizona and California, a few locations have captured the lion’s share of the film industry’s attention. What is it about these landscapes that makes them so photogenic? And how did they get that way?

In this episode, Craig Jones casts light on the answers to these questions. He is a Professor in the Department of Geological Sciences at Colorado University at Boulder. His research aims to uncover the origin of mountains and elevated topography in continents, primarily in the western United States. His main tool for doing this is seismology, but he also incorporates observations from other disciplines, such as gravity measurements, paleoaltimetry, and petrology. He has written a book on the Sierra Nevada and leads field trips to the rugged terrains we’re discussing here.

For podcast illustrations and to learn more about Geology Bites, go to geologybites.com. Follow Geology Bites on Twitter @geology_bites, @oliverstrimpel, and on Instagram oliverstrimpel.

Claude Jaupart on Whether the Earth is Cooling Down May 26, 2021

Show notes

We know the Earth was born as a baking inferno. So the presence of a relatively cool surface today suggests that the Earth has cooled a lot since it formed. But the very thin crust on which we subsist is not representative of the Earth as a whole, and although some heat must be escaping from the Earth, there are also ongoing sources of heat. So the answer to the question as to whether Earth is cooling down is not straightforward.

Claude Jaupart is Professor of Geophysics at the Université de Paris & Institut de Physique du Globe. His research aims to understand the physics of igneous processes in the Earth – such as those occurring in volcanic eruptions, magma chambers, and the mantle. He is especially interested in how heat flows out of the Earth, particularly in continents. In addition to advancing the geophysical theory of these processes, he has measured heat flow in the field, mostly in remotest Canada, where he discovered surprisingly low heat flow.

For podcast illustrations and to learn more about Geology Bites, go to geologybites.com. Follow Geology Bites on Twitter @geology_bites, @oliverstrimpel and on Instagram oliverstrimpel.

Peter Molnar on Why the Tibetan Plateau is So High May 13, 2021

Show notes

How can we tell what is happening at the bottom of the lithosphere, especially in one of the most remote places on the planet? Peter Molnar describes how many diverse lines of evidence, from the fossil record to normal faulting point to abrupt elevation changes in Tibet, both before and well after India collided with it. He thinks this tells us that the bottom of the thickened lithosphere there is gravitationally unstable and hot enough to literally drip off into the asthenosphere below, after which the remaining lithosphere becomes more buoyant.

Peter Molnar is Professor of Geological Sciences at the University of Colorado at Boulder. He has worked on a great many subjects, but especially on how mountain ranges are built and how climate on geological timescales is affected by topography and crustal movements. His research on mountain ranges has focused on the high terrain in Asia - the Himalaya, Tibet, and Tien Shan - all of which he has studied extensively in the field.

For podcast illustrations, and to learn more about Geology Bites, go to geologybites.com.

Katie Stack on Mapping the Geology of Mars with the Perseverance Rover May 08, 2021

Show notes

Katie Stack is Deputy Project Scientist for the NASA Perseverance rover that landed in Jezero crater on Mars in February 2021. A geologist by training and an expert on the Martian sedimentary rock record, she has been mapping the geology of Mars since the 2000s. She leads a large team of scientists that will combine orbiter and rover image data to investigate processes that took place on the the ancient surface of Mars.

She describes what we are learning with the powerful instruments aboard Perseverance as it traverses an ancient Martian river delta deposit.

For podcast illustrations, and to learn more about Geology Bites, go to geologybites.com.

Jan Smit on Resolving a Single Hour of the Cataclysm That Ended the Cretaceous 66 Million Years Ago May 03, 2021

Show notes

Jan Smit is a paleontologist who specializes in abrupt changes in the geological record. After the discovery of an end-Cretaceous surge deposit in North Dakota, he was part of the team that pieced together the striking evidence it contained, particularly its perfectly preserved fossils and tiny glass spherules called tektites. He describes how this led to a detailed picture of the dramatic events that unfolded within an hour or two following the asteroid impact.

Jan Smit is Emeritus Professor of Event Stratigraphy at the Free University of Amsterdam. Initially a paleontologist studying planktonic foraminifera, he became intrigued by what appeared to be extremely sudden events in the fossil record, especially at the boundary between the Cretaceous and the Paleogene, known as the KT boundary.

To see podcast illustrations as well as to learn more about Geology Bites, go to geologybites.com.

Marie Edmonds on Volcanic Gas Apr 30, 2021

Show notes

Marie Edmonds is Professor of Volcanology and Petrology at Cambridge University. She studies the cycling of volatile elements such as carbon between the atmosphere and the mantle and the role that volatiles play in melting, magma transport, and the style of volcanic eruptions. She describes how all volcanos emit gas and how the gas can reveal a lot about the origin of the magma and also forewarn of eruptions. Here is is monitoring gases emitted during the 2018 eruption of Kilauea on Hawaii.

For podcast illustrations and to learn more about Geology Bites, go to geologybites.com.

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