EPSS Colloquium - fall-2021


The Detrital Zircon Record of Phanerozoic Magmatism in the southern Central Andes

Sept. 28, 2021
3:30 p.m. - 6 p.m.
Chemistry CS50

Presented By:

  • Tomas Capaldi - Dept. Geoscience, University of Nevada at Las Vegas
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This talk will showcase how we can leverage zircon geochronology and geochemistry to track the evolution of continental magmatism in South America over the last 500 million years. I integrate this long-lived magmatic record with other geologic constraints to resolve competing geodynamic models that have been proposed to drive mountain building along subduction margins.


Characterizing the critical zone to advance understanding of water cycling and landscape evolution

Oct. 5, 2021
3:30 p.m. - 6 p.m.
Chemistry CS50

Presented By:

  • Suzanne Anderson - Dept. Geological Sciences, University of Colorado Boulder
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The critical zone, the region near Earth’s surface where water, air, rock and biota interact, is difficult to characterize and map. Yet the architecture of this region reflects the history of processes that shaped it, affects its current behavior, and constrains its future. In this talk, I will take a deep dive into the architecture, hydrology, and landscape evolution of Gordon Gulch, a headwater catchment in the Colorado Front Range to illustrate these points.


Ice in the Asteroid Belt: The Main-Belt Comets

Oct. 12, 2021
3:30 p.m. - 6 p.m.
Chemistry CS50

Presented By:

  • Henry Hsieh - Planetary Science Institute, Honolulu
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Main-belt comets (MBCs) are dynamically indistinguishable from main-belt asteroids, yet exhibit comet-like activity likely due to the sublimation of volatile ices. Their existence challenges long-held assumptions about the prevalence and nature of volatile material in small bodies in the warm inner solar system. I will discuss advances in our understanding of these enigmatic objects over just the last decade and a half since their recognition as a new class of cometary bodies, including efforts to discover more members of the population, physically and dynamically characterize individual objects and the population in general, and model their thermal evolution. I will also discuss prospects for future advances in this fast-developing field, especially involving upcoming facilities like the Vera C. Rubin Observatory and James Webb Space Telescope.


Connecting the Public with Science: Lessons from a Major Public Museum

Oct. 19, 2021
3:30 p.m. - 6 p.m.
Chemistry CS50

Presented By:

  • Rachel Smith - North Carolina Museum of Natural Sciences
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I will discuss why it is important to share scientific research with the public and give examples of how to create meaningful experiences in an informal education setting. Exhibits and programs in astronomy and planetary science at the NC Museum of Natural Sciences will be shown as examples of how to effectively engage the public. I will also present new software called OpenSpace, an open-source, interactive data visualization project that uses mission data and observations along with the latest visualization techniques to fly through the universe, and how we are currently using this software in exhibits, presentations, undergraduate education, and internships within museum spaces.


Determining how glaciers deform their beds

Oct. 26, 2021
3:30 p.m. - 6 p.m.
Chemistry CS50

Presented By:

  • Lucas Zoet - Dept. Geoscience, University of Wisconsin-Madison
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Many fast-moving glaciers sit atop a bed made of unconsolidated sediment that can deform in response to the stress applied by overriding ice. This deformation has ramifications for both glaciology and glacial geomorphology as its strain accounts for much of the glacier’s forward motion and produces some of the most iconic glacial landforms. In this lecture, I will talk about how we constrain this deformation using a novel cryosphere ring shear device capable of sliding a ring of temperate ice over an unconsolidated till bed at a range of realistic effective stresses and sliding velocities, while continuously monitoring sediment deformation.


The Chicxulub Impact Crater Hydrothermal System and Vestiges of a Subterranean Ecosystem

Nov. 2, 2021
3:30 p.m. - 6 p.m.
Chemistry CS50

Presented By:

  • David Kring - Lunar and Planetary Institute, Houston
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The Chicxulub impact crater is famous for its link to a mass extinction at the end of the Cretaceous, but is increasingly the focus of studies evaluating the resurgence and evolution of life in a post-impact setting. A recent expedition drilled into the Chicxulub peak ring demonstrating the crater had a porous, permeable subsurface environment; that the crater hosted a vast hydrothermal system; and that the system hosted a microbial ecosystem. The new finding is an important milestone and suggests that impact sites during the Hadean could have hosted similar systems that provided niches for the early evolution of life on our planet.


The NASA New Horizons Mission's Exploration of the Kuiper Belt

Nov. 9, 2021
3:30 p.m. - 6 p.m.
Chemistry CS50

Presented By:

  • Casey Lisse - Applied Physics Laboratory, Johns Hopkins University
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In this talk I will present the highlights of the New Horizons close flyby through the dwarf planet Pluto system and past the small KBO Arrokoth. My emphasis will be on the new findings produced by the first in situ targeted studies of KBOs, what they imply for the formation and evolution of the outer solar system, and what lies in store next for this ongoing mission.


Biomolecule fossilization products reveal the history of life on Earth and beyond

Nov. 16, 2021
3:30 p.m. - 6 p.m.
Chemistry CS50

Presented By:

  • Jasmina Wiemann - Dept. Earth & Planetary Sciences, Yale UniversityBiomolecule fossilization products reveal the history of life on Earth and beyond
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Proteins, lipids, and sugars are the fundamental structural building blocks of life. The tissues they generate contain molecular heterogeneities that inform about interrelationships (=phylogeny), biomineralization, tissue identity, and metabolic performance. Although such biological signatures have the potential to provide invaluable evidence of the evolutionary history of life and its building blocks, most molecular information is thought to be lost in deep time. Here I challenge the paradigm of the deep-time degradation of biomolecular signatures based on the first analyses of patterns in the molecular composition of carbonaceous fossils sampled across the tree of life, their associated sediments, and modern tissue equivalents. Statistical analyses of the molecular and mineralogical composition of fossils, and experimental modeling of observed reaction schemes, reveal that biomolecules transform during fossilization through oxidative crosslinking into N-, O-, S-heterocyclic polymers. Such endogenous fossil organic matter preserves heterogeneities reflecting phylogenetic and physiological signatures in living organisms. I will illustrate how diagenetic alterations of complex organic matter on Earth and in Space impact the preservation of biosignatures. Based on these insights, I will showcase how molecular signatures can be used to elucidate evolutionary responses to major environmental and ecological perturbations in the past, and to predict future biotic reactions to a changing climate. The broad range of potential applications places molecular biosignatures at the forefront of tools to access fundamental data on the interplay between the geosphere and biosphere previously hidden in the geological record.


Near-Earth Objects: Or, How I Learned to Stop Worrying and Love the Asteroids and Comets That Get Close to Earth

Nov. 23, 2021
3:30 p.m. - 6 p.m.
Chemistry CS50

Presented By:

  • Amy Mainzer - Dept. Planetary Sciences, University of Arizona
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Our solar system’s small bodies record aspects of formation and evolution that can be discovered by studying their dynamical and physical properties. While the rate of Earth impacts is relatively well-understood on geological timescales, the ability to determine whether a sizeable impact will occur in this century depends on measuring a similar set of orbital and physical properties. I will review the current state of knowledge and future prospects.


New Insights Into the Geology of Venus

Nov. 30, 2021
3:30 p.m. - 6 p.m.
Chemistry CS50

Presented By:

  • Paul Byrne - Dept. Earth and Planetary Sciences, Washington University
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With three new Venus missions recently announced by NASA and ESA, attention is once more turning to the second planet. In the past few years, a view has emerged of a much more dynamic world than we once thought. In this talk, I'll present an overview of our current understanding of Venus, followed by insights from two recent studies I've left to understand the planet's past and present properties—which can be tested by those new missions.