DeFord Lecture Series
DeFord Lecture Series Speaker Schedule
The DeFord (Technical Sessions) lecture series has been a requirement and a tradition for all graduate students since the late 1940s. Once the official venue for disseminating EPS graduate student research, the DeFord Lecture series is now the forum for lectures by distinguished visitors and members of our community. Faculty and researchers from the Jackson School have invited prestigious researchers from around the world to present a lecture in this series. This is made possible only through a series of endowments, such as those funding past Distinguished Lectures.
The list below shows all the scheduled talks this semester. If you would like to meet with any of the speakers, please contact them or their hosts directly.
DeFord Lecture Series 2023-24 Speaker Schedule
All talks are Thursdays from 4-5PM (CST) in the Boyd Auditorium (JGB 2.324). Lectures will be recorded, and most past lectures are posted on the Jackson School YouTube channel.
||Dr. Adam Atchley
Los Alamos National Laboratory
|Wildland Wildfire Science: Mechanistic models for understanding ecosystem and hydrological resiliency in a changing climate
Abstract: Over 70% of the terrestrial Earth is affected by fire in some way and roughly 50% of terrestrial ecosystems are fire dependent – meaning fire is necessary for these ecosystems to exist including the critical services these ecosystems provide such as carbon storage, and water resources. Climate change is rapidly changing Earths fire activity – we are now seeing larger and more extreme wildfires that are burning at times we have not seen before. Moreover, climate change in pushing conditions beyond the validation range of the empirically based models used to predict fire behavior and ecosystem response. This is referred to as the no-analog future, which necessitates a new fire modeling approach. Providing today’s society with the tools necessary to reduce wildfire risk, maintain ecosystem function – including water resources in light of climate change requires state of the art wildfire science that accounts for a rapidly changing landscape. Here at Los Alamos, we are working on the science necessary to reduce wildfire risk, while maximizing landscape carbon stabilization to mitigate climate change and protecting water resources – often in the form of safely reintroducing necessary fire to a landscape that has on one hand not seen fire in over a century and on the other requires fire for is very existence through the use of prescribed fire. This requires a multi-disciplinary approach that includes ecosystem science, hydrology, wildfire behavior, atmospheric chemistry, and use of physics based mechanistic models to capture a systems response in the no-analog future. I will be showcasing new wildland fire and ecosystem process-based models developed at LANL to understand how tightly entwine interactions of fire behavior, hydrology, and ecosystem structure drive ecosystem resiliency in a changing climate.
||Dr. Gabe Filippelli
Indiana University–Purdue University Indianapolis
|Managing the unmanageable: What else needs to be done to eliminate lead exposure to children?
Abstract: Albeit slow and not without its challenges, lead (Pb) emissions and sources in the United States (U.S.) have decreased immensely over the past several decades. Despite the prevalence of childhood Pb poisoning throughout the twentieth century, most U.S. children born in the last two decades are significantly better off than their predecessors in regard to Pb exposure. For example, in the 1970’s virtually every child in the U.S. would be considered Pb affected by today’s regulatory blood Pb standard, which is 5 micrograms/deciliter, with some variations among state health departments as to what level a given state begins case management for children. However, the rate of decline in blood Pb levels is not equal across demographic groups, with urban children and children of color exhibiting disproportionately higher average blood Pb levels than their non-urban and white counterparts. In part to address this disparity and to continue to reduce population and individual blood Pb levels, many U.S. federal agencies are moving quickly in various “Close to Zero” efforts, including newer regulatory guidance to further limit lead exposures.
The current state of lead exposure sources is much different than it was 40 years ago. For example, modern atmospheric emissions of Pb in the U.S. are nearly negligible since the banning of leaded gasoline in vehicles and regulatory controls on Pb smelting plants and refineries. This is evident in the rapid decrease of atmospheric Pb concentrations across the U.S. over the last four decades. One of the most significant remaining contributors to air Pb is aviation gasoline (avgas), which is minor compared to former Pb emissions. However, continual exposure risks to legacy Pb sources exist in older homes and urban centers, where leaded paint and/or historically contaminated soils and dusts can still harm children. Thus, while effective in eliminating nearly all primary sources of Pb in the environment, the slow rate of U.S. Pb regulation has led to still-significant legacy sources of Pb in the environment. Substantially more work is required to identify where legacy Pb sources are actively exposing children to harm, and substantially more resources, and new approaches, are needed to provide mitigation relief to parents. The presentation reviews the progress made in Pb abatement, its status, and discusses urban Pb exposure, and future research and regulatory needs.
||Dr. Peter Eichhubl
Jackson School of Geosciences, UT Austin
|Fracture growth processes under reactive subsurface conditions—Relevance for the New Energy Economy
Fracture systems and faults control the strength of the Earth’s crust, fluid flow, and heat and mass transport at a wide range of scales. In addition to the significance of fractures to natural crustal-scale and geomorphic processes, natural and induced fractures are of fundamental importance to oil and gas production, geothermal energy extraction, and the subsurface storage of CO2 and hydrogen. Understanding how fractures form, under what stress conditions, how fast, and how their growth is influenced by chemical reactions is of fundamental importance.
The formation of rock fractures under upper crustal conditions is conventionally regarded as a primarily brittle mechanical process. This view is now evolving with the recognition of the significance of coupled chemical reactions for fracture growth. This is particularly relevant to systems where the formation is in contact with fluid far out of chemical equilibrium, conditions expected for enhanced oil recovery, hydraulic fracturing, enhanced geothermal systems, CO2 storage, and hydrogen storage in porous formations.
In combination with field structural observations of fractures in a variety of natural settings, my students and postdocs conducted laboratory fracture mechanics tests of shale and sandstone of varying composition in the presence of aqueous fluid of varying pH and salinity to quantify the effect of chemical reactions on fracture growth. We also synthesized fractures in geomaterials under reactive laboratory conditions to define characteristics of fractures and fracture systems that form in chemically reactive systems and to understand how such reactive fracture systems differ from purely mechanical brittle fracture processes.
We find that chemical reactions can both enhance and inhibit fracture growth depending on the mineral and fluid composition and the reactions involved. Acidic pore water enhances fracture growth in carbonate-rich shale lithologies, whereas high salinity impedes fracture growth in clay-rich shales. Silicification under geothermal or epithermal conditions can lead to significant strengthening with a three-fold increase in fracture toughness, whereas chlorite-clay alteration reduces fracture toughness. Silicified rock is more susceptible to fracture growth under alkaline aqueous conditions.
Fracture growth experiments demonstrate that fractures formed in chemically reactive environments are generally characterized by wider kinematic apertures compared to fractures forming under less reactive conditions, with fracture shapes that deviate from predicted elliptical profiles. Such deviations in fracture profile may enhance or impede fracture growth.
These results apply to natural as well as engineered fracture systems and are thus of direct relevance to the stability of shale caprocks in CO2 and hydrogen storage systems, and to induced fracture performance in enhanced geothermal systems and unconventional oil and gas reservoirs. Because chemical reactions can both enhance and inhibit fracture growth, these processes provide the opportunity to optimize fracture outcomes under managed fluid chemical conditions.
||Dr. Atul Jain
University of Illinois Urbana-Champaign
|Water, Energy and Carbon Footprint from Bioethanol Production:
Bioethanol crops have the potential to meet future energy demands and mitigate climate change by partially replacing fossil fuels. However, the large-scale cultivation of these crops may also impact climate change through changes in land cover, terrestrial water and energy balance, carbon and other nutrient dynamics, and their interactions. This represents a pivotal challenge within the Food-Energy-Water System (FEWS) nexus. Our study estimates potential bioethanol yield across the US based on crop field studies and conversion technology analysis for three crops – corn, Miscanthus, and two cultivars of switchgrass (Cave-in-Rock and Alamo). This presentation will provide a detailed analysis of the implications of growing bioethanol crops on water and energy resources and GHG emissions. Additionally, the presentation will explore how the growing challenges of extreme climate conditions, including droughts and heat waves, are shaping these critical factors across the US.
||Dr. Alan Whittington
The University of Texas at San Antonio
|Space Lava! Adventures Beyond the Terrestrial T-X limits of Igneous Petrology
Abstract: As planetary geology reaches the edges of the solar system and prepares for the leap to exoplanets, we should be ready to encounter igneous processes occurring over a much wider range of T-X space than is familiar to terrestrial petrologists. Volcanism on Earth is typically restricted to compositions that can be generated by partial melting of the Earth’s mantle and/or crust, and through subsequent modifying processes such as magma mixing, assimilation, and fractional crystallization. This leads to the familiar range of terrestrial lava compositions, limited at the present day to foidites (e.g., Nyiragongo, DRC) at the low-SiO2 end, and high-silica rhyolites (e.g. Obsidian Dome, USA) at the other. Carbonatites represent a rare departure from silicate volcanism on Earth. At much lower temperatures, cryovolcanism is the probable mechanism for the extrusion of sodium carbonate-rich domes on Ceres. Sulfate, chloride, and carbonate-rich brines are likely cryovolcanic materials at Europa, Enceladus, and other ocean worlds.
Impact melts are composed primarily of target material, whose composition is dictated by surface processes that extend beyond the realm of igneous petrology. Consequently, they span a much wider range. On terrestrial bodies with primary crusts, such as the anorthositic lunar highlands, impact melts can resemble monomineralic melts, which could never form by any other mechanism. Where impacts remelt secondary crusts, for example the lunar maria, the same magma could be reborn but at a much higher temperature than during initial formation and emplacement. These superheated sheets of lava have tremendous erosive power, both thermal and mechanical, until they cool below their liquidus.
Finally, in situ resource utilization (ISRU) on the Moon or Mars will likely require melting to produce glass and ceramics for construction and technical applications. Energy requirements can be minimized by using starting materials with a glassy component, sourced from volcanic or impact melt deposits (including micron-scale agglutinates). The tendency for finer grained lunar regolith to also be more feldspathic and glassier raises the possibility that physical sorting by size can also sort for composition and crystallinity, facilitating brick/ ceramic production in locations where the bulk regolith is less suitable.
||Dr. Alex Bump
Bureau of Economic Geology, UT Austin
Not your grandfather’s petroleum system: The Goldrush for CO2 Storage and the Underrated Role of Pressure
Abstract: The Gulf of Mexico is a petroleum super-basin, a maker of fortunes and a major driver of American industry. Early indications are that it may be similarly spectacular for Carbon Capture and Storage (CCS), a key climate change mitigation technology. It has some of the densest clusters of point-source CO2 emissions in the US and proven reservoirs at every stratigraphic level from Jurassic to Pleistocene. Application of petroleum-inspired volumetric analysis suggests that the Texas coast Miocene section alone could offer 125Gt in storage capacity, enough to store ~2 decades of emissions for the entire US. Recent reforms to the tax code and passage of the Inflation Reduction Act have transformed the incentives for CCS, raising the reward from $10/ton of CO2 stored to $85/ton. As of November 2023, at least 49 new storage projects have been announced on the US Gulf Coast, with a total claimed storage capacity greater than 7Gt. A new gold rush is on.
However, CO2 injection is not petroleum production and application of petroleum-inspired volumetrics can yield dazzling but wholly unrealistic numbers. Both petroleum accumulation and CO2 injection require displacing pre-existing pore fluids (brines), but the similarity ends there. Petroleum accumulates on geologic time, pushing the native brines out slowly, at pressure equilibrium, and reliably saturating a predictable reservoir volume. Not so for injected CO2. Injection at industrial rates favors the highest permeabilities. Sweep efficiency is often poor and always hard to predict. More significantly, brine displacement is limited by faults, depositional edges and the same confining zones required to retain CO2. Most of the storage space for injected CO2 must come from compression of rock and preexisting brines, neither of which is very compressible. Pressure build-up is inevitable and it, not saturation, is the key limitation on storage capacity. Combined with the exponential growth of announced storage projects, that realization raises new questions: What is realistically achievable? What is the potential for interference between projects? What is the value of the storage resource? And how much space is required between projects to avoid interference?
To address these questions, we introduce the concept of pressure space, which we define as pore volume times allowable pressure increase, similar to a gas storage tank whose capacity is defined by volume and pressure rating. Using new algorithms on the grids developed for the original Miocene static capacity assessment, we find that the Texas coastal Miocene section offers ~10Gt in pressure-based capacity, if all reservoirs within it are pressured up to the statutory limit of 90% of frac pressure. While still substantial (and only a small fraction of the total Gulf of Mexico), that is an order of magnitude less than the original estimate and equates to less than 0.5% pore volume occupancy (storage efficiency), on average. For comparison, the 200+ saline storage projects in the global OGCI Storage Resource Catalog claim storage efficiencies from <1% up to 25%. While some may get these numbers, our work makes clear that they can only be achieved by producing brine and/or consuming pressure space beyond the project boundaries. Gigaton-scale storage is clearly possible, but it may require more acreage than current project developers are calculating. Competition for pressure space is predictable and like all gold rushes, this one is likely to yield benefit for society at large, but uneven fortunes for the project developers.
|Previous lectures for 2023-24
||Dr. Nicola Tisato
Department of Earth and Planetary Sciences, UT Austin
|Earthquakes Under the Lens of Rock Physics: From analog Materials in the Lab to Rocks in the Field
Abstract: Recent geophysical observations have revealed that faults and subduction zones deform through a complex spectrum of slip and deformation behaviors. Consequently, we still lack a full and comprehensive understanding of earthquake mechanics, limiting our ability to forecast earthquakes. I will present and discuss the results of two research projects that shed light on earthquake mechanics. Innovative rotary shear experiments paired with recordings of high-speed videos and acoustic emissions reveal that co-seismic slips trigger different weakening and strengthening mechanisms controlling the deformation along faults, suggesting that such dynamics may also be observed in seismograms. With the second study, I will show how rock-physics experiments, paired with CT scanning on sedimentary rocks from the Hikurangi margin, reveal how clay minerals play a fundamental role in controlling slow-slip events in the northern part of the North Island of New Zealand, providing help to mitigate earthquake geohazard.
||Dr. Timothy Shanahan
Department of Earth and Planetary Sciences, UT Austin
|Past to Future Climate: How can the paleoclimate record help us to understand the climate system and our future?
Abstract: The paleoclimate record provides unique insights into past climate variations and their causes, helping climate scientists to reconstruct how the climate system responds to forcings that are outside of the range experienced during the instrumental record. Evaluating how well climate models can simulate the responses to past forcings can also help to validate their response to anticipated future changes in the climate system, improving our predictions of climate under future warming scenarios. Here I will highlight three examples of this approach. The first will investigate the controls on the development of extreme storms over the southern Great Plains, the second will look at the role of critical atmosphere-ocean responses to a weakening of the Atlantic Overturning Circulation and the third will investigate the role of hemispheric warming on the development of North Pacific warming patterns and drought over the western US. Together, these approaches demonstrate several ways in which paleoclimate data, when combined with models, can help us to better understand the processes behind past climate changes, and to provide important insights into how those processes may drive future changes in the climate system.
|Sep 21||Dr. Elizbeth Catlos
Department of Earth and Planetary Sciences, UT Austin
|Aftershock: New Insights into the Dynamics of Himalayan Orogenesis provided by the 25 April 2015 Nepal Earthquake
Abstract: Since the pioneering studies of Himalayan tectonics, the orogen has been described as a fold-thrust belt with the most of the focus on the location, nature, and timing of its contractional structures. Lineaments within the Himalayan orogen were identified early on as remote sensing techniques advanced. Lineaments are relatively straight features expressed in topography and are not considered faults, or else they would be termed as such. Lineaments are often not included in orogen-scale maps and cross-sections of the Himalayas, although many of these features extend from the Indian craton and cut major Himalayan fault systems. After the devastating Mw 7.8 Gorkha earthquake on 25 April 2015 and its Mw 7.3 aftershock 17 days later, several geophysical studies identified the critical need to study Himalayan lineaments near the city of Kathmandu as two (Judi and Gaurisankar) appeared to influence rupture dynamics. These earthquakes were also unusual to the geologic community as their magnitudes were lower than predicted (Mw > 8 had been broadly advertised) and located far from the fault and decollement predicted to sustain the next major event. Unfortunately, most Himalayan lineaments are sparsely studied, and their locations are only published in papers or maps that are site-specific. This approach is a problem because lineaments appear to be significant in improving our understanding of Himalayan hazards. A new paradigm shift is also emerging in the aftermath of the devastating Nepal events, with Himalayan architecture appearing to be more like an accretionary wedge with internal microplates delineated by major Himalayan faults and nearby cross-cutting lineaments rather than a folded package of deformed and uniform lithological units. The Sikkim region of NE India is the first to be identified as a unique Himalayan microplate and the metamorphic history of its rocks helps develop new ideas regarding the assembly of the range.
|Sep 28||Dr. Prosenjit Ghosh
Indian Institute of Science
|Carbonate Clumped Isotopes Thermometry: A new tool for addressing the hydrological cycle and ocean circulation during Miocene optima and climate transition.
Abstract: Carbonate Clumped isotopes served as a unique tool for reconstruction of past temperature with confidence. This method has gained significant popularity amongst other competing techniques due to its ability to adequately define the temperature without knowing the isotopic composition of water. Nearly two decades of research engaged earth scientists in utilizing this new tool for addressing environmental condition for carbonate precipitation ranging from cosmos to benthos. The seminar will showcase a few new developments in the approach and provide a recent update on the scale for calibration of this novel tool for temperature assessment in carbonate samples from geological archives. Here, I will highlight some of our findings about environmental condition during mid Miocene and transition periods, which bear a large similarity with modern day Earth. The trends in hydrological conditions and extremes featured in the daily news channel broadcasts are encapsulated in the rock records preserved in the sedimentary libraries of the continental shelf and open ocean. We used the novel tool of clumped isotope thermometry on surface-dwelling planktonic foraminifera to investigate the thermal state of Miocene Ocean and the salinity condition over Indian Ocean, which are significantly influenced by the continental runoff and the biosphere.
|Oct 5||Dr. Emily Grubert
University of Notre Dame
|Planning the Mid-Transition: Aligning Fossil Phase-out and Zero Carbon Phase-in for Just Decarbonization
Abstract: Responding to climate change requires rapid and deep industrial transformation, particularly related to phasing out fossil fuels and restructuring energy systems to deliver services without greenhouse gas emissions. This transformation presents a critical opportunity not only to decarbonize, but to remake the way we provide energy services with emphasis on justice. The period of remaking is a multidecade effort that requires both phasing out the majority of the existing energy system and phasing in a new system — all while continuing to provide energy services effectively, despite the growing challenges of climate change and deep inequality. The “mid-transition” period during which existing and new systems are each too small to provide all services on their own, but too large to avoid constraining the other, poses special challenges of safety, reliability, flexibility, measurement, and other considerations, with many implications for policy. A successful transition will require extensive coordination and planning, especially due to the dynamism imposed by both technology and climate changes.
||Dr. Ken Belitz
United States Geological Survey
|The Quality of Groundwater Used for Public Supply in the Continental United States
Abstract: What is the quality of groundwater used as a source of public supply in the continental United States (CONUS)? More specifically: Which constituents are most prevalent at elevated concentrations? How many people are potentially affected? What are the hydrogeologic and geochemical characteristics of the aquifers where elevated concentrations are observed? These questions were addressed by evaluating the quality of groundwater in 25 Principal Aquifers (PAs) that account for 84% of the groundwater used for public supply in the CONUS (89.6 million people on a proportional basis). PAs are regionally extensive aquifers or aquifer systems that can provide large volumes of water for human use. Each PA was sampled across its lateral extent using an equal-area grid, typically with 60 wells per PA. Samples were analyzed for 502 constituents, of which 374 had either a regulatory or non-regulatory human-health benchmark. In all but three PAs, the most frequently detected constituent at elevated concentrations was a geogenic constituent. At the CONUS scale, geogenic constituents are more prevalent (based on area) and potentially affect more people than anthropogenic constituents. The occurrence of elevated concentrations is affected by aquifer type (lithology, location, and climate), pH, redox, groundwater age, and land use. The findings from this study (Belitz and others, 2022) can be used by managers responsible for providing safe drinking water, regulators considering which constituents might require additional scrutiny, and researchers seeking to identify groundwater quality issues of relevance to human health.Belitz and others, 2022, “Quality of Groundwater Used for Public Supply in the Continental United States: A Comprehensive Assessment,” Environmental Science and Technology – Water. doi.org: 10.1021/acsestwater.2c00390
|Robert H. Cuyler Endowed Lecturer|