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EPSS Colloquium - spring-2024

Chicxulub, Deccan, Tanis, and the Demise of T. rex and Friends

April 2, 2024
3:30 p.m. - 4:30 p.m.
3853 Slichter Hall

Presented By:

  • Mark Richards - U Washington
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The Deccan Traps flood basalt eruptions were approximately time-coincident with the Chicxulub impact in Yucatan, Mexico, which was likely the main cause of the end-Cretaceous (K-Pg) mass extinction that exterminated the non-avian dinosaurs at about 66 Ma. The Deccan eruptions were well underway at K-Pg time, but geological and geochronological evidence suggests that the magnitude Mw ~11 earthquake due to Chicxulub may have accelerated the Deccan eruptions at exactly K-Pg time. Although it is unlikely that outgassing associated with the Deccan eruptions was primarily responsible for the mass extinction, it is possible that these eruptions contributed to the climate disturbance that resulted in a prolonged recovery period. Recently, a remarkable paleontological discovery in North Dakota, suggests that seismic waves from the Chicxulub impact also caused a tsunami-like deposit along the existing Western Interior Seaway, capturing literally the last ~2 hours of the Cretaceous (or the first 2 hours of the Paleocene, depending on your point of view) in stroboscopic detail, including freshwater fish ingesting impact spherules from the water column before they were killed by ~10-meter water surges up a large river channel. Modeling and understanding the nature of this event, and likely similar events worldwide, promises to advance our understanding of the K-Pg mass extinction event. The excitation of Deccan eruptions by the Chicxulub impact likewise lacks detailed explanation. In other words, we have new and tantalizing clues as to events at K-Pg time that are perhaps much richer than previously imagined.

Collapse and Ejection in the N-body problem and the Formation of Rubble Pile Asteroids

May 7, 2024
3:30 p.m. - 4:30 p.m.
3853 Slichter Hall

Presented By:

  • Dan Scheeres - U. Colorado
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Rubble pile asteroids are thought to form in the aftermath of cataclysmic collisions between proto-planets. The details of how the detritus from such collisions reaccumulate to form these bodies are not well understood, yet can play a fundamental role in the subsequent evolution of these bodies in the solar system. Simple items such as how particle sizes and porosity is distributed within a body can have a significant influence on how they subsequently evolve. Current space missions are just starting to gain limited insight into these fundamental questions, but require a better theoretical understanding to fully explain their observations. This work studies how the initial energy and angular momentum of a random collection of gravitating bodies is partitioned and redistributed between escaping components and bound multiple body systems. A generic initial distribution of N bodies will naturally lose many components due to multi-body dynamical interactions. If the bodies have finite density, some components will also form condensed distributions, becoming single, binary or multiple component rubble pile asteroids. We derive and apply rigorous results from the Full N-body problem to place limits and constraints on how the energy and angular momentum of such systems can evolve, which controls the formation of stable rubble pile asteroids.

Climate as seen through the lens of Colorado’s Glaciers

May 14, 2024
3:30 p.m. - 4:30 p.m.
3853 Slichter Hall

Presented By:

  • Bob Anderson - Dept of Geological Sciences, University of Colorado
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Over the last couple million years, glaciers in Colorado and the American West have come and gone to the pace of global climate history. Only 20 thousand years ago we had many glaciers in the state, flowing down the valleys of nearly every mountain range. Yet very few features we would recognize as glaciers now exist in our mountains. I will introduce the history of climate and will discuss what has driven that history over this latest cycle of the ice ages. I will then focus on our own glaciers and how we have come to know their more recent history – chiefly their demise since the last glacial maximum 20 thousand years ago. I will then focus on the hundreds of odd glaciers that now dot our mountain valleys. These “rock glaciers” are cloaked with a layer of rocks that serves as something of a parasol to protect them from the heat, and at the same time prevent them from being recognized as glaciers. We are only now coming to understand how these glaciers work. I will show that a combination of modern speeds from feature tracking and exposure ages from 10Be concentrations constrains tightly the Holocene climate history of our mountains. Finally, I will use these rock glaciers to document the importance of lateral erosion of the headwalls, generating strong asymmetry of these ranges.

Progress in synchrotron multigrain diffraction techniques—exploring the petrology of Earth and planetary deep interiors

May 21, 2024
3:30 p.m. - 4:30 p.m.
3853 Slichter Hall

Presented By:

  • Claire Zurkowski - Lawrence Livermore National Laboratory
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Deep inside our planet and rocky planets in and beyond our solar system exist assemblages of silicate and metal phases exhibiting complex structures, chemistries, and interactions. Many of the key dynamic processes occurring within a planet are inherently linked to the physics of these minerals at depth. Exploring the interiors of rocky planets requires experimental techniques that can adequately probe complex phase assemblages under extreme pressures and temperatures. In this talk, I will discuss applications of the laser-heated diamond-anvil cell combined with synchrotron multigrain diffraction to explore deep planetary petrology: including, identifying new phases in Earth’s core, exploring core-mantle chemical reactions, and developing toroidal diamond-anvil cell techniques to apply these methods at super-Earth and sub-Neptune conditions. This work highlights ways in which multigrain diffraction can easily be incorporated into synchrotron experiments and the breadth of mineralogical information that this technique can provide at extreme pressures and temperatures.

CO2 Utilization and Storage via Carbon Mineralization and Integrated Recovery of Rare Earth Elements from Unconventional Resources

May 28, 2024
3:30 p.m. - 4:30 p.m.
3853 Slichter Hall

Presented By:

  • Ah-Hyung “Alissa” Park - Samueli School of Engineering UCLA
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With the increase in the global population and the growth of the world economy and industrial sector, global energy consumption has also been increasing. Considering that fossil fuels will still be one of the major energy sources for the foreseeable future, measures need to be taken to control the atmospheric CO2 concentration. Carbon capture, utilization and storage (CCUS) technologies are one of the approaches to decarbonize the power and industrial sectors. Among various options, mineral carbonation, which mimics the natural weathering of silicate minerals, has potential at scale relevant to climate change mitigation. As CO2 reacts with silicate minerals, carbon is stabilized in the form of insoluble solid carbonates for permanent carbon storage or CO2 utilization with permanence. If this reaction is carried out in an ex-situ reactor system, solid carbonates, high surface area silica and other minor components such as iron oxide can be produced with tailored properties and separated as value-added products. In addition to natural minerals and mine tailings, alkaline industrial wastes such as iron and steel slags can also be used as feedstock for carbon mineralization. Most of the industries producing alkaline solid wastes (e.g., steelmaking, cement, and aluminum plants) are also point sources of anthropogenic CO2. Thus, carbon mineralization using their own solid waste streams and CO2 leads to multifaceted environmental benefits including CCUS and solid waste management. Furthermore, industrial wastes often contain other valuable components such as rare earth elements. The challenge is that silicate minerals and alkaline solid wastes are chemically complex and their dissolution kinetics are very slow. In order to address these challenges and opportunities, we have focused on the fundamental understanding of dissolution and carbonation behaviors of alkaline silicate materials and the integration of step-wise separations of rare earth elements from these unconventional resources.

Volcanic landscape evolution and the intrinsic geometry of geomorphic process regimes

June 4, 2024
3:30 p.m. - 4:30 p.m.
3853 Slichter Hall

Presented By:

  • Leif Karlstrom - University of Oregon
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Volcanic provinces are among the most active but least well understood landscapes on Earth. In these terrains, long-lived but episodic and spatially patchy magmatic activity waxes and wanes in response to mantle melt supply and crustal rheologic state. Topographic evolution at the surface reflects a competition between construction by magma and climate-driven erosion, often confounding the standard models of geomorphology. I’ll talk about our ongoing work leveraging topography to understand time-evolving volcanism in the Cascade arc, and then about our efforts to quantify topographic curvature using tools of differential geometry. This new curvature-based approach seems extremely promising for disentangling the competing processes that shape volcanic provinces, and may provide insight into many other landscapes as well.