Events

UTIG Seminar Series: Marianne Karplus, UT El Paso

Speaker: Marianne Karplus, Associate Professor, Earth, Environmental and Resource Sciences, The University of Texas at El Paso

Host: Ginny Catania

Title: Echoes from the edge of Thwaites Glacier, Antarctica: from tectonics to ice flow dynamics

Abstract: The Thwaites Interdisciplinary Margin Evolution (TIME) project illuminates the control that shear margin dynamics have over the future evolution of ice flow in the Thwaites-Amundsen drainage basin. To examine the physical processes and properties at the shear margin, we set up field geophysical observatories between 2019 to 2024 at several locations along the shear margin to study the ice as well as the geology below. I will present results from our seismicity study, describing earthquakes and icequakes recorded by two 7-station passive broadband seismic networks deployed between 2019-2021. Then I will present preliminary images and observations from 2-D and 3-D controlled-source seismic surveys acquired across the Thwaites shear margin in 2023-24, with 1000 3-component seismic nodes deployed in a 27-km line and 3 by 5.5-km seismic grid. We detonated 671 seismic sources, mostly “Poulter” sources with 4-kg explosive boosters suspended on a 6-foot bamboo pole. The seismic signals were recorded across the full extent of the seismic line and grid and penetrated into the bed beneath the ice (~2000-km-thick), allowing for englacial, bed, and geologic imaging and interpretation.

Bureau of Economic Geology Seminar Series

DeFord Lecture | Dr. William Dietrich

The shock of the familiar: Observations on Mars raise questions about Earth surface processes by Dr. William Dietrich, Department of Earth and Planetary Sciences, University of California Berkeley

Abstract: Evidence from satellite imagery of features like channel networks, gullies, meandering rivers, alluvial fans, and deltas abound on Mars.  These provide crucial evidence that in the past, at various times, Mars had an atmosphere that supported a liquid water hydrologic cycle.  These features make the Martian landscapes one sees (in close up rover-derived imagery) seem strangely familiar: Earth-like but lacking any vegetation.  In my talk, I will describe our rover encounter with two very different alluvial fans and a pediment surface, which raised unanticipated fundamental questions about fan and pediment processes and the hydrologic signals they may record. Mars meandering river observations also motivated our field and modeling study of a channel on Earth that explains how lateral accretion deposits can form in muddy meanders.

DeFord Lecture | Dr. Bill Dietrich

The shock of the familiar: Observations on Mars raise questions about Earth surface processes by Dr. William Dietrich, Department of Earth and Planetary Sciences, University of California Berkeley

Abstract: Evidence from satellite imagery of features like channel networks, gullies, meandering rivers, alluvial fans, and deltas abound on Mars.  These provide crucial evidence that in the past, at various times, Mars had an atmosphere that supported a liquid water hydrologic cycle.  These features make the Martian landscapes one sees (in close up rover-derived imagery) seem strangely familiar: Earth-like but lacking any vegetation.  In my talk, I will describe our rover encounter with two very different alluvial fans and a pediment surface, which raised unanticipated fundamental questions about fan and pediment processes and the hydrologic signals they may record. Mars meandering river observations also motivated our field and modeling study of a channel on Earth that explains how lateral accretion deposits can form in muddy meanders.

UTIG Seminar Series: Gavin Piccione, Brown University

Speaker: Gavin Piccione, Postdoctoral Research Associate in Environment and Society, Brown University

Host: Ruthie Halberstadt

Title: Constraints the Oxygen Isotope Composition of Antarctic Ice Recorded in Subglacial Rocks: A Case Study from the Late Miocene

Abstract: Long-term, continuous records of global ice volume have been derived using δ18O values of benthic foraminifera (δ18Ob), which record the balance between water held in the ocean and trapped on the continents. However, these ice volume approximations are confounded by the fact that δ18Ob values change as a function of ocean bottom water temperature and cannot account for spatiotemporal variation in the ?18O of ice sheets. Therefore, direct constraints on the ?18O of ice sheets are necessary to link the ?18Ob record to sea level change. In this talk, I will present geochemical data from Antarctic subglacial opal and calcite precipitates, a novel archive for reconstructing ice sheet ?18O values. Uranium-series and uranium-lead dating reveal the formation histories of these samples, spanning the late Pleistocene to late Miocene. Paired carbonate clumped isotope temperature estimates and opal triple oxygen measurements characterize the oxygen isotope composition of basal ice. Using a simplified mass balance calculation, I will explore the mass and sea level contributions of the late Miocene Antarctic Ice Sheet given these newly defined oxygen isotopic constraints.

Bureau of Economic Geology Seminar Series

DeFord Lecture | Dr. Carl Tape

DeFord Lecture | Dr. Carl Tape

Exploration of Seismic Anisotropy of Earth Materials and Alaska Structure by Dr. Carl Tape, Department of Earth and Planetary Sciences, University of California Berkeley

Abstract: For many seismologists, seismic anisotropy is a complex nuisance. Yet it is undeniably present in the Earth, from the scale of crystals like feldspars to metamorphic terranes to the uppermost mantle. Alaska offers an exciting testbed for exploring anisotropy, with insights from exhumed mantle rocks, corner flow at the edge of a subduction-collision zone, and foliated metamorphic units and other fabrics in the crust. One of the grand challenges of seismology is to estimate the variations in subsurface anisotropic elastic properties using seismic waves recorded at the surface. I will discuss how this challenge can be faced with efforts from realms of theory, computation, laboratory, and observation.

UTIG Seminar Series: Kate Rychert, WHOI

Speaker: Kate Rychert, Associate Scientist, Woods Hole Oceanographic Institution

Host: Thorsten Becker

Title: A dynamic lithosphere-asthenosphere boundary: the PI-LAB experiment

Abstract: Plate tectonics revolutionized our understanding of how the Earth works, providing a framework for volcanism, earthquakes, continental formation and breakup and the geologic record of climate change. Yet, what makes a plate “plate-like” and where and how the rigid lithospheric plate transitions to the underlying weaker asthenosphere are widely debated. I present new geophysical constraints on the LAB from the PI-LAB (Passive Imaging of the LAB) experiment using a range of methodologies, techniques, and resolutions in one location near the equatorial Mid-Atlantic Ridge. We find that the LAB has a variable character depending on location: simple, with monotonic age progression, undulating, and underlain by a thin melt channel. The result reconciles seemingly discrepant and variable reports of the LAB and partial melt from previous studies. Putting the LAB result from the Mid-Atlantic Ridge in the context globally, in particular, by considering a new interdisciplinary compilation of LAB depths, suggests that temperature determines the thickness of the plate to first order. However, the LAB is dynamic. Composition, in addition to melt generation and migration also affect the depth and definition of the LAB and likely play a role in driving plate tectonics.

Hot Science - Cool Talks: "This is Your Brain on Birth Control"

Birth control has revolutionized fertility control, but its effects extend far beyond reproductive health. The powerful hormones in birth control influence billions of cells throughout the body, particularly in the brain, shaping stress responses, eating habits, romantic attraction, and more. Join Hot Science – Cool Talks for an enlightening discussion with Dr. Sarah Hill as we explore the hidden impacts of birth control and empower everyone to make informed decisions about their health and well-being. (Recommended PG-13)

Bureau of Economic Geology Seminar Series

DeFord Lecture | Dr. Sumant Nigam

DeFord Lecture | Dr. Saravanan Ramalingam

The Limits of Predictions: Weather vs. Climate by Dr. Saravanan Ramalingam, Department of Atmospheric Sciences, Texas A&M University

Abstract: Prediction plays an important role in the physical sciences. Knowing the mathematical equations that govern a physical system and its initial state should, in principle, allow us to compute the future time evolution of the system. In practice, our ability to predict is limited by how well we know the equations and the initial state. Awareness of these limits can guide us in setting priorities for predictive model development and help calibrate our expectations for improvements in model performance.
In this talk we address the limits of scientific prediction, with a focus on weather and climate prediction. The talk will discuss the philosophical underpinnings of weather and climate prediction. The evolution of modern weather and climate prediction is intertwined with advances in computing. Since the advent of the digital computer, physics-based “deductive” models have been used for weather and climate prediction. However, recent advances in machine learning have opened the door for a new class of “inductive” models for weather and climate. Climate models have also grown in complexity over time as computers have become more powerful. However, in the most recent IPCC assessment, some of the most complex models have been criticized as being too sensitive to carbon dioxide concentrations. This suggest that increased model complexity may be yielding diminishing returns in reducing uncertainty.

UTIG Seminar Series: Eloi Camprubi Casas, UT Rio Grande Valley

Speaker: Eloi Camprubi Casas, Assistant Professor, The University of Texas Rio Grande Valley

Host: Elizabeth Spiers

Title: On wet rocky worlds – How does origin of life research impact space exploration efforts at ocean worlds?

Abstract: Many settings have been proposed as the cradle of life on Earth. Amongst these, Hadean alkaline hydrothermal systems have been proposed as electrochemical reactors driving an autotrophic origin of life. Recent experimental discoveries demonstrate some of the crucial synthetic steps are indeed favored under these conditions. We have developed a high-pressure microfluidic reactor to simulate the out-of-equilibrium conditions found in these extreme submarine environments. How does this research impact the strategy for biosignature detection at Ocean Worlds? What role does the icy surface environment play when trying to detect signs of life? This talk will present the work done at the Astrobiochemistry Lab at UTRGV connecting abiogenesis and biosignatures research.

Bureau of Economic Geology Seminar Series