Tuesday, April 1st

Glaciology I

Dominik Graeff The Limits of Fiber Sensing: What we did not learn from towing a vertical fiber-optic cable through a Greenlandic fjord.

Fjords with ocean-terminating glaciers are the bottlenecks through which liquid and solid discharge from the Greenland Ice Sheet—namely meltwater and glacier ice—is guided from calving fronts towards the ocean. During this journey, subglacial discharge and icebergs modify fjord waters, impacting bio productivity, the food chain, and local fisheries. Mixing cold glacially sourced freshwaters with warm oceanic waters may also influence the fjord circulation close to glacier termini and alter the frontal ablation of calving glaciers.

To resolve this process, we towed a vertical fiber-optic cable from a vessel along a Greenlandic fjord. Using Distributed Temperature Sensing (DTS), we turned the cable into an array of more than a thousand temperature sensors. This allowed us to measure the fjord water temperature with 25cm vertical and meter-scale horizontal resolution. What did we learn? Mainly, the limits of fiber sensing, what it can be useful for, and what it cannot.

Margot Shaya New observations of Allan Hills ice velocities: implications for ancient ice preservation 

Antarctic ice cores preserve records of Earth’s climate history going back over a million years; however, ice flow over millennia disrupts the continuous stratigraphy of the oldest ice, resulting both in units of anomalously deforming ice at the base of the ice sheet (“basal units”) as well as discontinuous outcroppings of ancient ice near the margins of the ice sheet. Understanding the preservation of old ice is necessary to target exploration of future ice coring sites and to interpret the climate signal of discontinuous ice. The Center for Oldest Ice Exploration (COLDEX) has concentrated its search for ancient ice on the Allan Hills blue ice area, where wind-driven sublimation and flow over steep topography uplift old ice towards the surface. In addition to drilling shallow ice cores in the disturbed ice near the rock nunatak, COLDEX proposes to drill an upstream intermediate depth (~1000 m) ice core, which seeks to capture a 1 Ma record with more stratigraphic context. Here we present new measurements of surface and englacial velocities calculated from repeat GNSS and interferometric radar acquisitions across the Allan Hills region. Interestingly, the vertical velocity measurements suggest that there is a basal unit at the proposed site, where ice flows over a bump in the bedrock. Future work will use these velocities to further investigate the potential for old ice preservation at the proposed intermediate depth site. 

John-Morgan Manos Cryo-seismic source localization using distributed acoustic sensing (DAS) on Eastwind Glacier, Antarctica

Glaciers on the coast of Antarctica often have floating ice shelves that buttress the glacier and act to slow the flow of ice into the sea. However, both the ice shelves and the grounding line or where the ice shelf meets the grounded ice are sensitive to the environment. Additionally, ice fracture or motion along the bed may destabilize ice shelves and compromise their buttressing force. In this study, we utilize distributed acoustic sensing (DAS) to interrogate a fiber optic cable deployed near the grounding line of Eastwind Glacier, Antarctica to identify and localize ice fracture and basal icequake events. Inversions for event locations identify crevassing events originating from nearby crevasse fields and events that originate deep in the glacier possibly caused by basal icequakes or basal crevassing. Wave velocity inversions generally agree with accepted values in glacial ice and firn in addition to providing an easier way to distinguish event types. By effectively identifying a range of cryo-seismic events, we may be able to provide a first-of-its-kind catalogue of cryo-seismicity as recorded by a DAS array.

Glaciology II 

Daniel Otto Evaluating Near-Surface Temperature Lapse Rates on the Juneau Icefield

Models of glacier change commonly parameterize melt as being proportional to near-surface temperature. A standard approach is to downscale temperature from global climate model projections to the local topography using near-surface temperature lapse rates – the rate of temperature change with elevation. Although widely used, the limitations of the lapse-rate parameterization for glaciers remain poorly understood. The Juneau Icefield, a glacier complex in Southeast Alaska, presents a unique natural experiment to investigate these limitations. The icefield spans the transition between maritime and continental climates along a continuous ice surface. During the 2025 field season, we will deploy a dense network of inexpensive temperature sensors across this climate transition. These data will enable comparison of observed lapse rates with the theoretical expectation of adiabatic temperature change across an orographic barrier. By comparison with an analogous ice-free ”control” transect, we will test whether lapse rates on the icefield are distinct from non-glacierized areas. Together, these analyses will yield insight into the role of glaciers in determining their local climate. This work will advance our understanding of near-surface temperature in glacier environments and its use in modeling glacier change. 

Liam Kirkpatrick A New Framework for Interpreting Allan Hills Ice Core Layering

Recent ice core samples from the Allan Hills blue ice area in Antarctica extend ice core chronologies as far back as 6 million years. These cores promise to unlock new insights into evolution of earth’s climate through the Pleistocene, by providing the first direct records of atmospheric composition through this time period. However, the interpretation of this ancient ice is limited by contamination with basal material, layer mixing, and uncertain preservation histories. Addressing these critical questions requires novel approaches to ice core sampling at high resolution. Here we provide a discussion of dip-adjusted sampling, enabled by 3D Electrical Conductivity Measurements. We identify clear layers of integrated basal material in ice near the bed. In younger ice, we explore the potential for preservation of climate variability in water isotope samples. These measurements provide new insight into the composition and origin of stratigraphy in these cores, and may provide a framework for interpreting these complex records.

Paleoclimate, Paleontology & Sedimentology 

Benjamin Lloyd A deep learning approach to the phylogenetic placement of grass silica short cell phytoliths

Phytoliths, microscopic silica bodies that infill plant tissues, have proven highly useful for tracking grasses and grasslands in deep time, due to the distinct morphologies of Grass Silica Short Cell Phytoliths (GSSCPs) affording more taxonomic specificity than largely non-diagnostic Poaceae pollen and leaf fossils. However, the precision with which GSSCPs can be identified to subclade—or even genus/species—in the fossil record is limited by the difficulty and subjectivity of phytolith morphotype classification. Deep learning approaches to image segmentation and classification offer new tools to standardize and streamline phytolith classification. These methods have the potential to uncover previously unrecognized connections between morphology and phylogeny, expanding researchers’ ability to interpret fossil phytolith assemblages. We are adapting newly developed pollen classification methods to phytoliths with a robust training set of 7,023 GSSCP images obtained from vouchered herbarium specimens of 111 species spanning all twelve Poaceae subfamilies. Trained convolutional neural networks (CNNs) achieve ~75% accuracy in species classification, significantly above the 0.9% expected by chance. We next transform CNN classification features using a second machine learning model (multilayer perceptron, MLP) trained on known phylogenetic distances. The MLP-transformed features are then used to place fossil phytoliths on the Poaceae phylogeny using Bayesian inference.

Henry Yuan Decoding Shapes in the Sedimentary Record

Geologists have long studied the sedimentary record to address questions about the age, depositional environment, biological influence, and provenance of rocks. One particularly useful property of sedimentary rocks for reconstructing Earth history is the morphology, or shape, of physical features, which encodes information about formation, transport, and deposition. However, it is not always easy to analyze shape. For example, geologists may only have access to two-dimensional (2D) cross sections of objects (e.g., a thin section or a single face of rock), which can provide incomplete information about three-dimensional (3D) form. One object in the sedimentary record whose shape can reveal information about ancient environments is the detrital zircon (ZrSiO4). While the isotope geochemistry of detrital zircon grains provide information about depositional age and provenance, some aspects of the shape of zircons (e.g., roundness, aspect ratio, ...) hold additional information about their past, including transport history and provenance. Here, I present an effort to quantify the 2D and 3D shapes of zircons to extract their transport histories. Specifically, I investigate whether 3D zircon shape data are necessary for accurate analyses or if 2D data suffice. Furthermore, I will examine whether zircon grains that researchers have polished for radiometric dating via laser ablation still retain valuable information in their shapes. I also outline my plan to apply similar shape analysis methods to a type of stromatolite in order to investigate its possible abiotic origins.

Emma Heitmann Lacustrine carbonate isotope stratigraphy of the Miocene Bidahochi Formation records both short-term and long-term environmental change, Navajo Nation, AZ, USA

We present a surface temperature record from the of the 16-6 Ma Bidahochi Formation, located on the southern CP in Navajo Nation, AZ. The Bidahochi Formation is significant because it has potential to record significant events such as the evolution of the Colorado River, tectonism of the southern Colorado Plateau, and regional response to major global climate change of the mid-late Miocene. We sampled carbonates at high resolution from consistent lithofacies in the most profundal parts of the Bidahochi basin to control for environmental changes. In both the stratigraphy and isotopic record, we observe large variations on millennial timescales that cannot be attributed to tectonics or secular climate change but may instead record a dynamic lake system sensitive to Milankovitch cycles. We also observe a long-term cooling in the record consistent with global climate trends, but the magnitude of which may be significantly larger which could imply tectonic uplift. We present hypotheses and recommendations for future work to disentangle the controls on the temperature record. 

Hannah Cothren What’s my age again? Complexity and clarity with U-Pb zircon geochronology at the dawn of animal life.

Diverse, macroscopic animal-grade fossils appear for the first time during the late Ediacaran Period (574-538.8 Ma)These organisms are exceptionally preserved in life position by rapidly deposited volcanic ash and turbidites at Mistaken Point and Catalina Dome in Newfoundland, Canada. This style of preservation captures “snapshots” of both species and entire seafloor communities. It has enabled studies of individual species, their life histories, and their ecologies, including  reproductive strategies, ecological succession, and interspecies relationships. However, our understanding of their spatial and temporal distribution—and how they relate to other roughly coeval changes in the Earth system— remains limited due to a lack of precise age constraints. Robust age constraints are essential for constructing a precise timeline of early animal life. Establishing this timeline is critical to unraveling causal relationships between organisms and their changing environment, quantifying evolutionary rates, and placing local events in a global context.

The zircon-bearing ashes interbedded with these fossil communities offer a rare opportunity for high-precision (<0.2 Ma) U-Pb zircon dating using chemical abrasion isotope dilution thermal ionization mass spectrometry (CA-ID-TIMS). The strata at Mistaken Point and Catalina Dome are traditionally correlated across hundreds of structurally complex kilometers, without independent absolute age constraints or chemostratigraphic support for this margin scale correlation. The canonical correlation model suggests Catalina Dome fossils are younger than those at Mistaken Point. However, emerging geochronologic data challenge this view, and indicate that the commonly accepted correlation of these locations is erroneous, which obscures environmental and evolutionary trends.  I will present a preliminary high-precision U-Pb zircon CA-ID-TIMS age model for Catalina Dome in support of my alternative model, suggesting contemporaneity with Mistaken Point. My results support the hypothesis that animal-grade life emerged and rapidly dispersed across regions. I will also share new dates from key ashes at Mistaken Point that resolve conflicting U-Pb zircon CA-ID-TIMS age models, clarifying the age of the earliest known animal fossils in Newfoundland. Only by doing this work, can we fully understand what, if any, and how broader changes in the Earth system accompanied, triggered, or followed the rise of early animals.

Trent Thomas Fundamental aspects of Snowball Earth revealed by a global carbon cycle model

The Cryogenian Period (720-635 Ma) witnessed two Snowball Earth glaciations: the Sturtian, which lasted 56 Myr, and the Marinoan, which was as short as 4 Myr. Despite extensive study over many decades, many fundamental properties of the Snowball Earth events remain unconstrained. Here, I will discuss progress on two major open questions: why did the Snowball Earth events end? and why do they differ by up to 14 times in duration? A new model of the geologic carbon cycle provides answers.

Poster Session I (Astrobiology & Planetary Science, Geophysics, and Glaciology)

Jade Wells Small Microbes, Big Questions: How Were Two-Billion-Year-Old Microbial Buildups Organized?

Stromatolites are fossilized, centimeter-to-meter scale laminated buildups formed by microbial activity. When examined, these sedimentary structures offer insights into the emergence of early life on Earth. However, before we can use stromatolites as a tool to study early life, we must understand what their morphology (e.g., shape and spatial arrangement) tells us about their formation. To date, few studies have quantified exactly how such variables affect stromatolite morphology. Here, I produce and apply morphological metrics to two-billion-year-old stromatolites to test two hypotheses: 1) the distribution of the individual constructions is non-random and 2) the space between stromatolites varies in thickness across space. To investigate these hypotheses, I use digital three-dimensional (3D) reconstructions of ancient stromatolite bedding planes from Great Slave Lake, Canada and make measurements. I identify the organizational patterns of these stromatolites using metrics such as area, width, length, aspect ratio, and circularity distributions across space, and explore whether such patterns are indicative of life. Ultimately, this work will broaden scientific understanding of stromatolite morphogenesis and the processes that drive early Earth systems; knowledge that may help us better interpret potential signs of life found elsewhere in our solar system. 

Danqiu Chen Stardust in the chamber: high temperature chemical simulation of shooting micrometeorites

Micrometeorites are considered a potential proxy for reconstructing atmospheric oxidant levels over time, especially in the Precambrian. Upon entry into Earth's atmosphere, frictional heating can partially or completely melt these stardust particles, allowing them to incorporate oxygen atoms from the surrounding atmosphere. This process occurs rapidly, typically within a few to several seconds, thereby recording the contemporaneous atmospheric oxygen and/or carbon dioxide levels. Here, we use a self-designed high-vacuum inductive furnace and introduce pure CO2 to simulate the Archean upper atmosphere. The furnace can melt iron within 30 seconds (1811 K), providing new insights into the reaction kinetics between molten iron and CO2 to estimate a lower limit for Archean CO2 by analyzing contemporary micrometeorite fossils.

Andrea Nodal Measuring the Bioenergetics of FS406-22: a hyperthermophilic methanogen

To better understand early Earth environments and guide our search for life elsewhere, we must constrain the range of environmental conditions on early Earth that would have been necessary to support early life. Thus, calculating the energetic requirements of early life on Earth would improve habitability models. Given that nitrogen is required for all life on Earth and is not bioavailable as N2 gas, having a better understanding of the energetic implications of biological fixation is an essential piece to understanding bioenergetics in early Earth conditions as a whole. Hyperthermophilic methanogen, FS406-22, is an ideal candidate to represent the needs of life on the early Earth. It shares metabolic strategies believed to have been employed by the last universal common ancestor (LUCA), and is able to fix nitrogen. Here, we use microcalorimetry, chemical analyses, and thermodynamic modeling to determine the energetic cost of FS406-22 incubations under fluctuating nitrogen conditions from 65-85o . Preliminary results at 65o  suggest that growth is more efficient under nitrogen fixing conditions. This is a surprising find given that nitrogen fixation is understood to be an energetically intensive process. However, there may be significant differences in how this energy is divided into biosynthesis. This work aims to better understand the thermodynamics of growth under varying temperatures and nutrient conditions, further constraining the limitations of life, and informing the selection of target sample sites. 

Anna Pearson Influence of Non-Tidal Atmospheric Loading on Slow-Slip Events on the Nankai Subduction Zone

This study assesses the influence of non-tidal atmospheric loading on the probability of slow-slip event initiation on the Nankai Subduction Zone in Japan, using a statistical framework. We create curated datasets of slow-slip and tremor events from a global compilation, along with atmospheric pressure data and the associated surface loading. Permutation and Mann-Whitney U tests are applied to evaluate the statistical significance of these relationships. The analysis identifies a statistically significant, although modest, correlation between extreme short-term atmospheric loading changes and the onset of slow-slip events. This correlation is supported by modeled Coulomb failure stress values that, although lower in magnitude than those from tidal forces, indicate the potential for triggered slow-slip. We also investigate seasonal modulation of slow-slip due to atmospheric loading, although find those results to be inconclusive due to inconsistencies across different regions. These findings highlight the complex interactions and sensitivity of fault systems to small stress perturbations, as well as the importance of additional research into how surface loading, including atmospheric, tidal, hydrologic, and other sources, can interact with fault behavior and seismic hazards.

Andrew Sparks Evaluating the Effectiveness of Past and Present Seismic Arrays in Detecting Off-Shore Earthquakes in Cascadia

The Cascadia Subduction Zone is known to produce devastating large-magnitude earthquakes. Rapidly detecting and locating offshore megathrust earthquakes can be difficult using current seismic station network geometries. Dense arrays and advanced array processing techniques offer the potential for more accurate locations and earlier detections for both small and large earthquakes. This study evaluates the effectiveness of incorporating small-aperture seismic arrays (<2 km) to improve the accuracy of locating offshore and out-of-network events.  It focuses on data from earlier array experiments and a new array near Forks, installed specifically for this purpose. Using modern FK-based array processing techniques, we evaluate the potential improvements arrays can bring to the Pacific Northwest Seismic Network's routine operations and the USGS ShakeAlert earthquake early warning system. Preliminary results indicate that using the arrays helps constrain early initial earthquake locations within 1000 km.  Enhancing offshore earthquake detection and location is crucial for effective earthquake early warning in Washington and Oregon, and seismic array methods show significant potential to improve the Pacific Northwest Seismic Network’s capabilities.

Alex Rose & Anjani Mirchandani Toward Foundation Models for Distributed Acoustic Sensing

Distributed Acoustic Sensing (DAS) is a geophysical tool that utilizes fiber-optic cables as a way of geophysical monitoring. It transforms the fiber-optic cable into an array of single-component seismometers at a given spaced interval. A major hurdle when utilizing DAS data is large output size of every file of raw data, which makes data analysis difficult. Our preliminary work focuses on utilizing Machine Learning to reduce the computational time required for data processing.

Data processing in geophysics has multiple tasks. The most basic ones are denoising, event detection and discrimination, and seismic phase picking: some of these are regressions, some of these are classification. Given the multiple tasks and massive data volume, there is an opportunity to build a general feature extraction model framed as a “foundation model”. We start this exploration with two tasks 1) denoising, 2) phase picking. We first test the base models (Shi et al, 2025; Rose et al, in prep) independently by applying them within-domain but on different types of events (e.g., car noise vs ocean noise). We also test general out-of-domain models for image segmentation, leveraging the HuggingFace model shared space, though unsuccessful at handling complex geophysical data. We present here the building blocks and the roadmap of a bigger task of foundation models using the UW Fiberlab DAS data.

Hiroto Bito Earthquake catalog building offshore Cascadia: detecting obvious and hidden earthquakes using deep learning

The Cascadia Subduction Zone  (CSZ) stretches offshore from Vancouver Island, Canada to Northern California, United States. It is the result of subduction of the Juan de Fuca plate beneath the North American plate. Although the subduction zone is known to host earthquakes of magnitudes up to M9 and subsequent tsunamis, it has low seismicity compared to other subduction zones. In this study, cataloging of newly detected events are performed by incorporating Ensemble Learning Earthquake Prediction (ELEP) for phase picking and Graph Earthquake Neural Interpretation Engine (GENIE)  for association and relocation, with high weight on detecting new events offshore Washington. The study uses seismic data from Cascadia Initiative (CI) and onshore stations operating from 2010 to 2015. The spatial extent of the stations is determined to improve the stability during association. The associated events from this workflow are then compared to catalogs by Morton et al., (2023) and USGS-ANSS to discover previously undetected events. Those newly found events are manually checked to test the validity of the workflow.

Claire Jensen Investigating Seasonal Glacier Fluctuations in Northeast Greenland Using Physics-Informed Machine Learning

The Greenland Ice Sheet is losing mass due, in part, to the recent speedup of many of its outlet glaciers, including Zachariæ Isstrøm (ZI), a large outlet glacier in the northeast region of the ice sheet. Not only does ZI play an important role in the ice sheet’s surface mass balance, but it exhibits marked seasonal variability, observed in both glacier flow speeds and the terminus position. Compared to its neighbor Nioghalvfjerdsfjorden (79N), ZI does not have a floating ice tongue and is predicted to retreat much faster despite being subject to similar environmental forcings. More recently, studies on a small number of large outlet glaciers have also linked the formation, build-up, and subsequent break-up of proglacial mélange to seasonal variability through its impact on the timing of glacier advance and retreat. Still, the relative impact of these variables on glacier flow and to what extent they propagate further upstream remains unclear. Here, I propose to characterize seasonal patterns of glacier flow and retreat at ZI and 79N to determine how meltwater, mélange, and terminus position drive changes in ice velocity and gain insight into the glaciers’ potential future changes. This study will expand our knowledge of the history of two significant Greenland glaciers and create a baseline for understanding the environmental drivers of seasonal glacier change.

Lesly Silva Reconstructing the Paleoclimate 34 Ma Using Fossil Leaves in the Oligocene Wenatchee Formation, Central Washington State

From the Eocene to the Oligocene (40 to 32 million years ago [Ma]), central Washington State underwent significant environmental changes, which are recorded in the sedimentology and paleobotany of the Chumstick and Wenatchee formations. The Wenatchee Formation, in particular, spans the Eocene-Oligocene Transition (EOT; ~34 Ma ), which was a major global shift from a warm “greenhouse” world to a cooler “icehouse” climate. While prior studies have focused on the Chumstick Formation, the fossil plant record of the Wenatchee Formation remains understudied. This project explores what the fossil flora of the Wenatchee Formation can reveal about regional climate during the EOT. To investigate this, I am analyzing floristic data using the Climate Leaf Analysis Multivariate Program (CLAMP), which infers paleotemperature and paleoprecipitation based on leaf morphology. I will also study plant fossils in the field to document their stratigraphic and sedimentological context. By integrating these approaches, I aim to test the hypothesis that the Wenatchee Basin reflects a shift toward cooler, drier conditions in the Oligocene. Ultimately, this research will elucidate how climate influenced plant communities and depositional environments in the Pacific Northwest during a pivotal moment in Earth’s history. 

Wednesday, April 2nd

Geologic Hazards & Society

Jess Ghent When every second counts: Parental decision-making in Mt. Rainier’s lahar inundation zone

Mt Rainier, a heavily glaciated stratovolcano within Washington, has a history of generating major lahars - dense, lethal mudflows containing water, ash and other volcanic materials, boulders, and debris. Past lahars form the deposits underlying many current towns near Rainier and have even reached as far as Tacoma. The ongoing possibility of high-magnitude flows poses a substantial risk to 150,000 people downstream, necessitating one of the densest monitoring networks in the USA. This network includes a purpose-built lahar detection system within certain valleys, as portions of Rainier's west flank comprise unstable, hydrothermally altered rock that renders these catchments vulnerable to a "no-notice" lahar derived from a sudden, non-eruptive slope failure. Consequently, for over 20 years, local schools have performed lahar evacuation drills which are now legally mandated. These drills have demonstrated that the most effective way to remove students from the lahar inundation zone is on foot. However, parents have reported intentions to collect their children from school during an emergency lahar evacuation, regardless of evacuation recommendations. Such behavior would place parents directly in the lahar's path and obstruct the emergency response. In areas where lahar arrival times are very rapid (<1 hr), parent behavior is an essential consideration for the success of city-wide evacuations.

While many studies have discussed lahar hazards, preparatory efforts, and expected behavior in the region, the rationale behind parents' intentions during school evacuations remains poorly understood. To address this gap, my research explores the influence of perceived proxy efficacy, or the perceived effectiveness of K-12 school-led emergency lahar evacuations among parents in lahar inundation zones near Mt Rainier. This presentation will highlight my ongoing effort to survey local parents and examine factors contributing to their decision-making during lahar emergencies. Surveyed topics include personal perceptions of lahar risk, confidence and intentions during evacuation, and perceptions of family reunification plans and resources (e.g., food/water/shelter) at school evacuation sites. The results from this work may help emergency managers better understand and meet the needs of parents in these vulnerable communities.

Madeline Lucas Active strike-slip fault system accommodates oblique convergence at the Cascadia Subduction Zone

An outstanding question in our understanding of tectonics at the Cascadia Subduction Zone is how shear strain due to oblique convergence of the Juan de Fuca and North American plates is partitioned among forearc faults. Mechanical modeling predicts that oblique convergence should be accommodated by margin-parallel strike-slip faults within the accretionary wedge. However, no such margin-parallel faults have been documented as active at the Cascadia margin and it is widely accepted that oblique convergence in Cascadia is instead accommodated by a series of margin-perpendicular strike-slip faults within the central Cascadia forearc. Through our joint structural-geomorphic analysis of recently acquired seismic and bathymetric datasets offshore central Cascadia, we have identified a system of active, margin-parallel strike-slip faults within the upper continental slope spanning up to 100 km along strike between ~45-46°N, hereafter referred to as the Albatross Fault system. The Albatross Fault system is located just to the north of the Fulmar Fault system as mapped by Snavely (1987). A prominent NE-SW trending seafloor scarp related to this fault system is captured by USGS 30-m bathymetry and is observed to offset older NW-SE trending seafloor ridges, likely related to the inactive Fulmar Fault system, in a right-lateral sense of motion. The subsurface structure of this fault system is well-imaged by both deep-penetrating CASIE21 and near-surface USGS sparker seismic images. We find that the deep structure of this fault system can be directly linked to vertically dipping offsets in wedge top sedimentary basins. Overall, the Albatross Fault System represents a candidate system of active margin-parallel strike-slip faults that work to accommodate oblique convergence at the Cascadia margin and likely hosts faults that will slip in future Cascadia Subduction Zone earthquakes.

Chi-Ying Huang Integrating Environmental and Social Parameters to Assess Risk and Coastal Resilience along the U.S. Gulf Coast

Effective risk management requires a comprehensive understanding of hazards, vulnerabilities, and exposures to develop mitigation strategies and support recovery efforts. This study examines spatial variations in social and environmental vulnerability in the U.S. Gulf Coast, including Louisiana (LA), Mississippi (MS), Alabama (AL), and Florida (FL).

This research explores two key questions: (1) how the Social Vulnerability Index (SVI) differs between coastal and inland areas and (2) how social factors influence environmental conditions along the coast. The study utilizes ArcGIS Pro to visualize and analyze data from the 2018–2022 five-year estimates of the American Community Survey (ACS), SVI datasets from the Centers for Disease Control and Prevention (CDC) and the Agency for Toxic Substances and Disease Registry (ATSDR), and digital elevation models (DEMs) from The National Map (TNM) of the U.S. Geological Survey (USGS).

The preliminary findings will assess the relationship between social and environmental vulnerability in communities at risk and examine the interconnections within risk management. The outcomes of this study will provide policymakers, stakeholders, and community leaders with data-driven insights to develop effective mitigation strategies. It will help reduce vulnerability and enhance resilience to climate change impacts—particularly sea level rise—in both urban and rural coastal regions of the U.S. Gulf Coast.

Geophysics

Veronica Gaete-Elgueta Distributed Acoustic Sensing for earthquake source parameter studies at Cook-Inlet, Alaska (CI-DAS)

Distributed acoustic sensing (DAS) has recently emerged as a powerful tool for seismologists, offering high spatial and temporal resolution and relatively low deployment and maintenance costs. Historically, offshore seismic instrumentation has been limited by the complexity of installation and instrument recovery. In this study, we repurpose two offshore telecommunication cables to form a dense 160 km array in Cook Inlet, a forearc setting characterized by a large, deep sedimentary basin. 

This region experiences significant seismic activity from slab and crustal earthquakes. However, the lack of dense seismic networks limits the quality of focal sphere observations. Dense focal sphere data are crucial as they provide insights into rupture velocity and, therefore, fault rupture style.  Our study aims to capture and analyze a wide range of earthquake types to extract detailed information on their source characteristics and propagation effects.

The high-density instrumentation provided by DAS is essential for accurately constraining earthquake source parameters and site effects, offering new insights into seismicity in this region.

Manuela Köpfli Listening to Mount Rainier to track ground moisture

Monitoring near-surface environments is critical for landslide risk mitigation. However, traditional methods like soil sensors and satellite imagery often lack spatial detail. Distributed Acoustic Sensing (DAS) offers a solution by using fiber-optic cables to continuously record strain along the fiber, providing high spatial and temporal resolution without invasive techniques. This makes DAS a promising tool for tracking subsurface conditions such as soil temperature (freeze-thaw cycle) and soil moisture, key factors in landslide risk assessment. Monitoring changes in these is crucial for predicting landslide susceptibility. By using DAS, we aim to assess how environmental factors, including vegetation, lithology, and weather exposure influence landslide risk.

Jensen DeGrande Validation of ShakeMaps created using Global Navigation Satellite Systems (GNSS) velocities

Ground velocity observations generated through a time difference of Global Navigation Satellite Systems (GNSS) phase observables and orbits have been shown to be comparable to seismic recordings without clipping during intense ground motions. Computing GNSS velocities is also computationally scalable and increases the density of ground motion observations during significant earthquakes, so their inclusion into ShakeMaps can potentially improve rapid assessments of strong ground motion. In this presentation, I propose the creation of ShakeMaps with GNSS velocities and validate them against currently published results. I focus on the 2016 M6.6 Norcia event with the goal of expanding this validation set to demonstrate the broad applications for a variety of earthquake rupture characteristics and regional instrument coverage. Where co-located geodetic and seismic observations exist, I quantitatively assess any biases between the ShakeMaps produced with different datasets and the velocity waveforms themselves. In addition to these formal comparisons, I compare the GNSS-derived velocities and the ShakeMap-inferred peak ground velocities (PGVs) directly. Lastly, I assess the optimal weighting between intensity observations produced with Peak Ground Acceleration (PGA) and PGV with this new addition of velocity data. This work shows that including geodetic data, specifically GNSS velocities, can help further constrain the interpolation schemes used in ShakeMaps and potentially lead to a better constraint on ground motions and shaking intensity realized for different earthquakes observed by real-world irregular sensor network geometries. These small changes could have major downstream effects when it comes to hazard and disaster response which we will explore with future work. 

Yiyu Ni Cloud computing for big data seismology: example from the earthquake catalog building

Seismology is increasingly becoming one of the leading big-data fields in geosciences: seismograms from more than 70k seismometers are surpassing 1 PB on the EarthScope seismic data archive. As the paradigm of the traditional data processing paradigm faces difficulties when the data volume rapidly increases, cloud computing provides a novel and transformative solution for both data centers and big-data seismologists.

In coordinate with the EarthScope’s effort migrating the entire seismic archive to the Amazon Web Service, we exemplify and develop a cloud-native workflow for the base steps of earthquake catalog building. Empowered by the direct access to the cloud-based data archive, our workflow exhibits massive parallelization that enables scanning the entire archive within weeks using Machine Learning-based detection and classification approaches. The workflow populates a database of global first arrival phase picks, which leads the first step towards a comprehensive catalog of earthquakes and exotic events.

Akash Kharita Beyond Earthquakes: Machine Learning for Detecting and Classifying Surface Events

Accurately detecting and classifying seismic events is crucial for understanding geophysical processes and mitigating hazards. While significant progress has been made in distinguishing earthquakes and explosions, the detection and characterization of surface events—such as avalanches, landslides, and debris flows—remain a challenge due to their complex waveform signatures and variability. This research leverages machine learning (ML) and deep learning (DL) techniques to develop a robust seismic classification system tailored for surface event detection in the Pacific Northwest (PNW). Using seismic waveform data from regional networks, we train convolutional neural networks (CNNs) and other advanced ML models to classify events into earthquakes, explosions, surface events, and noise. Additionally, we explore feature attribution methods to enhance interpretability and understand the distinguishing characteristics of surface-generated seismic signals. Our results demonstrate that deep learning models can effectively discriminate surface events from other seismic sources when trained on diverse, high-quality datasets. This work contributes to improving real-time seismic monitoring and broadening our understanding of near-surface geophysical phenomena.

DEI, Outreach & Education

Chloe Anderson Disaster Dialogue: Interpreting Volcanic Hazards at Craters Of The Moon

With over 25 cinder cones, Craters Of The Moon National Monument is the largest lava field in the lower '48 and a shining example of basaltic volcanism. How do we leave visitors more informed about the geohazards in the park and beyond? 

Claire Jensen Geologic History of Black Graduate Students at UW

In 1973, the University of Washington (UW) admitted its first ever Black student to pursue a graduate degree in geology. 52 years later, only nine Black students hold a graduate degree in geology from UW, with the most recent student graduating in 2011. The geosciences have a diversity problem, and UW is no exception. Research shows that a lack of inclusivity is a major reason for lower diversity and retention rates in higher education. Recent changes in administration regarding diversity, equity, and inclusion beg the question: has the diversity problem changed in 50+ years? Here, the soon-to-be ninth student will share memories from interviews with students from the 1970s, complemented by her own experiences, highlighting just how diverse geology is and has been.

Maro A. Savvides & Garret Stromberg Washington Rocks in Thin Section: Petrified Wood & Twin Sisters Dunite 

Stromberg: Petrographic thin sections provide insight into the mineralogical composition, structure and formation of rocks.  As part of a project to produce large thin section prints for the walls of Johnson Hall, I used equipment in the recently renovated ESS Student Rock Lab to produce a high-quality thin section of petrified wood From Washington State. Petrified wood is the state gemstone.  The sample was obtained commercially as Washington State petrified wood, but the exact origin and plant species are unknown. 

Petrified wood may contain crystalline quartz polymorphs (β-quartz, cristobalite, and tridymite) and amorphous opal species, all of which are difficult to distinguish in thin section (Mustoe and Dillholt, 2022). This section is primarily composed of fine-grained silica, which has replaced the original organic material, preserving the cellular structure of the wood. A photo-mosaic of the section will be displayed, and we invite viewers to identify structures preserved in the wood.

Savvides: Washington has a rich geologic history which may be communicated to the public through the presentation of thin sections. Displaying local rocks in thin section by way of high resolution photography can increase people's understanding of and interest in geology.

GeoClub Bridging the Gap: How Faculty Can Better Support Self-Driven ESS Undergraduates in the Field

Being undergraduates with limited experience in the field, student leaders struggled to form a cohesive field trip guide and itinerary for the trip, but thankfully received guidance from the ESS Community.  Because of their assistance, this year ESS geology club explored the Colorado Plateau, experiencing the dynamic geological history of Utah, Nevada, and Arizona. During Spring Break, students traveled through iconic landscapes, including Red Rock Canyon, Zion National Park, Coral Pink Sand Dunes, Vermilion Cliffs National Monument, and the Grand Canyon. This trip allowed students to learn about the complex formation of sedimentary rocks, desertification, human impacts on geology, and the uplift and erosive history of the Colorado Plateau. On this trip, students independently studied and shared various aspects of the Colorado Plateau; these unpolished undergraduates could reach their full gleam through faculty mentorship and other ESS support.

Poster Session II (Paleoclimate, Paleontology & Sedimentology, Geologic Hazards & Society, Structure, Petrology & Tectonics)

Caleb Tidwell Assessing Dinosaur Diversity of Microsites from the Judith River Formation

The Campanian stage of the Cretaceous (~84–72 million years [Ma]) was a pivotal time for North American ecosystems. Fossil-rich formations throughout the Western Interior of North America preserve the dynamic events of this time interval, including the zenith of dinosaur diversity, the radiation of angiosperms, and the transgression and regression of the Western Interior Seaway. Studies that investigate dinosaur biodiversity during this interval use data obtained from macrosites (e.g., skeletons), whereas few investigate vertebrate microfossil sites. Vertebrate microfossil sites are perfect for investigating biodiversity   changes through time because they preserve large sample sizes and information about the depositional environment. The Judith River Formation of north central Montana is rich in vertebrate microfossil sites, preserving 4 million years of the Campanian (~79–74 Ma). Here, we aim to observe patterns of dinosaur diversity in the Judith River Formation by quantifying dinosaur taxonomic richness and relative abundances based on dinosaur teeth from three stratigraphically and temporally separated microfossil sites: Makela-French 1 (~77.5 Ma), Milkshake (~76.5 Ma), and Clamfetti (~75.2 Ma). We collected sediment samples from these sites over four years and processed them for vertebrate microfossils. At present, we have recovered 600 dinosaur microfossils. Our preliminary results reveal a change in dinosaur diversity between these three sites. Rarefaction analyses indicate that dinosaur families in the lower part of the formation are at their most diverse and decline in diversity in the middle part before increasing again in the upper part of the formation. We hypothesize that observed patterns could be driven by taphonomic and ecological factors. Taphonomic factors may lead to a bias in our record due to the differences in the depositional setting between the sampled localities. Furthermore, changes in the depositional setting may reflect subtle environmental differences not observable in this study. Additionally, the ecology and evolutionary patterns of dinosaur families may explain why some of the abundance trends observed in Milkshake, like the decline of ankylosaurs and the increase of hadrosaurs, persist in Clamfetti. Our continued collection of fossils and the lithographic analysis of Makela-French 1, Milkshake, and Clamfetti will increase our sample size and provide better fine-scale resolution of dinosaur diversity patterns during this crucial interval of their evolution.  

Hailey Germeau Deconvolving Seasonal, Environmental, and Climatic Variability in Paleotemperature Records: A Clumped Isotope Approach to Understanding Lake Carbonate Accumulation

Paleoenvironmental reconstructions are key to understanding changes in climate, ecosystems, and surface processes over time. Lake carbonate archives in particular offer a continuous, high-resolution, multi-proxy record of past terrestrial environments. Among these, the carbonate clumped isotope thermometer has emerged as a powerful tool for reconstructing paleotemperatures (T△47) independent of source water composition. However, carbonate accumulation may be biased to brief seasonal intervals and different water-column depths, complicating mean annual air temperature (MAAT) reconstructions from T△47 data. While some studies have attempted to account for these biases, the depth and timing of carbonate formation can vary significantly due to climatic and environmental controls, highlighting the need for quantitative sensitivity analyses to assess how depositional environments affect lacustrine carbonate proxies. Here, we adapt the existing lake proxy system model, PRYSM (Dee et al., 2018), incorporating a carbonate clumped isotope sensor to explore the effects of seasonal timing and depth of carbonate formation on the proxy record.  Using climate model outputs to set the boundary conditions for PRYSM’s lake environment model, this sensor model prescribes temporal and depth-weighting parameters to simulate carbonate accumulation and produce synthetic T△47 observations. This approach allows us to directly compare climate model outputs, including air temperature and simulated PRYSM water temperatures, with T△47 clumped isotope data, integrated over depth and seasonal timing by the sensor model. By testing various hypotheses for the depth and timing of lake carbonate formation, we examine how these factors may influence the climate record, using climatic and topographic scenarios from the Colorado Plateau as a case study.

Sofia Kaiaua Development of High-Precision Eu Purification for Isotope Characterization

Europium (Eu) is a redox-sensitive rare earth element (REE). Eu stable isotopes are promising tracers across different scientific domains, giving quantitative insight to the processes where Eu anomalies are present. Studies on Eu isotopes remain scarce as the chemical separation of Eu from other REEs is challenging due to their geochemical similarities, as well as low concentration of Eu in standard geological materials . Recent development of a high-yield (99.4%) and low blanks (<20 pg, Wu et al., Anal. Chem. 2024, 96, 15102−15107) Eu purification scheme from geological materials using cation exchange resin and extraction chromatographic resin allows for an effective approach to better characterize Eu isotope compositions in various materials.

We aim to investigate this method of purification and instrumental analysis technique to obtain  δ 153/151Eu values with a multicollector-inductively coupled plasma-mass spectrometry (MC-ICPMS) instrument. To achieve this, we will replicate the purification protocol established by Wu et al. (2024) with synthetic solutions and digested geological reference materials (GRMs), monitoring the relative intensity of Eu and other matrix elements. We collect pre- and postcut fractions of samples to determine the Eu yields and potential contamination from other elements using MC-ICPMS. To correct instrumental mass bias, Wu et al. (2024) used combined standard-sample-bracketing-internal-normalization method, with internal normalization using Nd and standard reference material NIST 3117a as the bracketing standard. Building on the protocol by Wu et al. (2024), we will additionally investigate the effect of column geometry, acid molarity, as well as instrumental analysis without element doping on yield and precision. The validation of the method used for accurate and precise Eu isotope analysis allows for increased applications of Eu isotope geochemistry.

Filip Novak The Osteoderms of Bunostegos akokanensis (Parareptilia: Pareiasauria) from the Upper Permian of Niger 

Bunostegos akokanensis is an early pareiasaur known from the middle to late Permian-aged Moradi Formation of northern Niger. Pareiasaurs were large, herbivorous parareptiles that are known for their bony armor, otherwise known as osteoderms. However, current descriptions of pareiasaur osteoderms are often inconsistent or unclear. Here, we present a detailed analysis of the osteoderms of B. akokanensis based on a large, presumably mature, individual. Overall, the arrangement of osteoderms in Bunostegos aligns with its understood phylogenetic position, being nested between basal bradysaurs, which possess rows of minimally ornamented, sutureless, osteoderms above their vertebral column, and the more derived velosaurs, which show suturing, extensive osteoderm body coverage, and complex ornamentation. Bunostegos possesses articulated osteoderms in the neck (cervical) and back (dorsal) regions, which are arranged in four longitudinal rows. Unique among other pareiasaurs, these osteoderms are sutured together into patterned groups of six or eight, and exhibit various osteoderm morphologies. Although relatively small, many of the osteoderms possess subtle radiating ridges and a high degree of suturing to their neighbors. Another pareiasaur specimen from the Moradi Formation, which likely belongs to a juvenile Bunostegos, tentatively suggests the presence of more extensive osteoderm cover earlier in life. Based on this description, we propose that the osteoderm features we observe here be more closely considered in future cladistic analyses of pareiasaurs.

Nijah Coleman Stable Isotopes in Leaf Wax n-Alkanes as a Record of Ambient Climate Through the Transition Into Soil Organic Matter

Stable isotopes in precipitation serve as recorders of hydrological processes and have potential as paleoclimate indicators. The deuterium/hydrogen ratio (δ2H) in precipitation is controlled by climatic and geographic factors such as temperature, elevation, and latitude. As terrestrial plants use atmospheric water as their primary source of hydrogen, these climatic and topographic markers are recorded in their compounds. This study examines δ2H in n-alkanes, the hydrocarbon chains that make up plant leaf waxes, from sites throughout an east-west transect across the Cascade Mountains in Washington State. Plant n-alkanes are retained through the transition into leaf litter and then into soils, which represent a long-term average of plant communities and ambient climate conditions. The goal of this project is to assess the relationship between modeled atmospheric water δ2H and n-alkane δ2H values along the precipitation, temperature, and elevational gradient created by the Cascade Mountains, and to look into the pathway of isotopic signature from plant tissue into soils that has not been well studied. Samples of plants, leaf litter, and soils were collected across northern WA and n-alkanes were extracted from these samples and analyzed for δ2H via mass spectrometry. This research aims to provide new insight into the pattern of isotopic signals preserved from live plants into the soils, which will have implications for the use of hydrogen isotopes in sedimentary n-alkanes as a paleoclimate proxy. 

Sophia Robillard Decoding Lacustrine Carbonates of the Colorado Plateau: How Depositional Environments and Processes Shape the Stable Isotope Record​

Lacustrine carbonates serve as critical archives of past environmental conditions, with stable isotope compositions, ¹³C and ¹⁸O, providing insights into depositional processes and climate reconstructions. However, the extent to which depositional environments and biological processes influence these isotopic signatures remains unknown. This study investigates lacustrine carbonates from the Bidahochi Formation of the Colorado Plateau to assess the relationship between depositional environment, micro-facies characteristics, and isotopic variability, with implications for interpreting the clumped and stable isotope record. Through petrographic analyses of carbonate thin sections, we aim to identify textural and biological features that may contribute to isotopic homo- or heterogeneity. Preliminary observations suggest that depositional environment could play a role in shaping ¹³C and ¹⁸O variability, with potential influences from biological activity. However, further analyses are needed to determine the extent and consistency of these relationships. This ongoing study seeks to refine our understanding of lacustrine carbonate isotope records and evaluate the significance of micro-facies characterization in paleoenvironmental reconstructions.

Gabriel Goncalves Santana Floodscapes of the Eastern Himalaya: The Geomorphic Footprint of Megaflood Deposits

Catastrophic outburst floods occur due to the failure of landslide, glacial, or debris dams and have the potential to reshape Earth's surface and other planetary landscapes through intense geomorphic activity. With discharges exceeding 10⁶ m³/s, these events can cause immediate erosional impacts, threatening communities downstream of natural and man-made dams. While it is known that such events transport and deposit immense volumes of sediment, ranging from fine silts to massive boulders, the long-term effects of megaflood deposits on river dynamics and landscape evolution remain largely unexplored. Recent hydraulic simulations of megafloods in the Yarlung-Siang-Brahmaputra River in the Eastern Himalayas suggest that flood-topography interactions can alter bed shear stresses and flow characteristics. Geomorphic process models of channel profile evolution indicate that megaflood boulder deposits can create steeper, more stepped channels, with over 100 knickpoints, each reaching up to 3.5 m in relief. However, it remains unclear whether natural megaflood landscapes align with these predictions. This study aims to analyze topographic differences between rivers with a history of megaflooding (Siang) and those without (Subansiri) in the Eastern Himalayas by comparing channel steepness, width, and knickpoint formations using high-resolution topographic data. Future work will involve numerical simulations of suspended sediment transport to investigate the interplay between flood hydraulics and river terrace morphodynamics during a megaflood. The results will advance fluvial geomorphology by addressing the knowledge gap regarding the long-term impacts of megaflood deposits on landscape evolution, with implications not only for over 40 terrestrial landscapes but also for planetary surfaces.

Bering Tse Evaluating tsunami deposits at Lagoon Creek (Del Norte county, CA); a sediment record of Cascadia megathrust earthquakes

In Cascadia, tsunami deposits in coastal wetlands record megathrust earthquakes. Analyzing them provides critical hazard information about recurrence intervals, coseismic subsidence, and amount of earthquake slip. Our field site, Lagoon Creek, is a rare location in the southern part of the Cascadia Subduction Zone (CSZ) with good preservation of tsunami deposits. This site contains a record of 5 tsunami events within the top 4 meters of sediment. Using radiocarbon analysis and statistical modelling techniques, we are improving the age constraints on these deposits and estimates of tsunami recurrence interval. Additionally, we are mapping sand layers and microfossil evidence across the site in order to determine the inland inundation extent of the January 1700 tsunami. Improving chronology and mapping of tsunami deposits at Lagoon Creek will contribute to understanding spatial variability of past CSZ ruptures, and support a more complete understanding of subduction zone coastal hazards.

Xinkai He Investigating Volatile degassing in Cascade arc

Gas loss from ascending magmas controls the physical and chemical evolution of arc volcanic systems. Olivine-host melt inclusion (MI) is a powerful tool to study pre-eruptive conditions. Here, we systematically examine compositions of olivine-hosted melt inclusions from basal c to basalt-andesitic magmas erupted at Indian Heaven Volcanic 

Field (IH). We investigate a preliminary dataset to answer the ques on of how S, Cl and Cu change as a function of water, oxygen fugacity and melt compositions.

Maro A. Savvides Washington Rocks in Thin Section: Twin Sisters Dunite

Washington has a rich geologic history which may be communicated to the public through the presentation of thin sections. Displaying local rocks in thin section by way of high resolution photography can increase people's understanding of and interest in geology.

Garrett Stromberg Washington Rocks in Thin Section: Petrified Wood 

Petrographic thin sections provide insight into the mineralogical composition, structure and formation of rocks.  As part of a project to produce large thin section prints for the walls of Johnson Hall, I used equipment in the recently renovated ESS Student Rock Lab to produce a high-quality thin section of petrified wood From Washington State. Petrified wood is the state gemstone.  The sample was obtained commercially as Washington State petrified wood, but the exact origin and plant species are unknown. 

Petrified wood may contain crystalline quartz polymorphs (β-quartz, cristobalite, and tridymite) and amorphous opal species, all of which are difficult to distinguish in thin section (Mustoe and Dillholt, 2022). This section is primarily composed of fine-grained silica, which has replaced the original organic material, preserving the cellular structure of the wood. A photo-mosaic of the section will be displayed, and we invite viewers to identify structures preserved in the wood.

Thursday, April 3rd

Astrobiology & Planetary Science I

Chris Woodburn Breaking the Ice: Activity of an Ice-binding Peptide at High Pressure  

Pressure is a key environmental parameter that governs the viability of living systems. Extremophiles, especially those existing at high pressures, represent an ongoing area of interest in the search for extraterrestrial life on other planetary bodies. Icy worlds like Titan, Ganymede, Europa, and Callisto host oceans in equilibrium with ice polymorphs up to pressures ten times higher than those found on Earth. However, there has been little research on the upper limits of well-defined, life-preserving mechanisms at gigapascal-level pressures. Inspired by the resilience of fish, beetles, and vegetables to subzero conditions, the activity of an ice-binding peptide is investigated versus a non-hexagonal, high-pressure phase of ice. Fundamental experiments reveal that peptides can affect the recrystallization of ice VI similar to how antifreeze materials operate under normal conditions. This work opens up new areas of research on the habitability of ice-covered ocean worlds.

Haskelle White-Gianella Carbon Cycle Instabilities on Arid Terrestrial Planets with Implications for Venus

Arid terrestrial planets with low surface water inventories may be a common outcome of planetary evolution. On Earth, the surface water inventory is sufficient to permit high continental weathering fluxes, thereby maintaining habitable conditions via a silicate weathering thermostat. However, shallow oceans on arid planets might limit continental silicate weathering, jeopardizing the balance with volcanic outgassing of CO2. 

Here, we apply a geologic carbon cycle model to terrestrial planets with low surface water inventories (<<1 Earth ocean) to explore if they can remain habitable despite secular changes in instellation and outgassing. Our model couples outgassing/weathering, stellar evolution, planetary hypsometry, and the deep-water cycle. Crucially for the exploration of arid planets, precipitation is limited by wind-driven evaporation or direct heating from sunlight, which is justified by comparisons to GCM outputs.

We find that the carbon cycle stability is sensitive to surface water inventory. As expected, on a planet with Earth-like water inventories, the carbon cycle is balanced, and surface temperatures are relatively stable on geologic timescales as the silicate weathering feedback buffers against secular stellar evolution. In contrast, an arid planet with a low surface water inventory enters a regime where silicate weathering cannot keep up with degassing, and the carbon cycle is unbalanced. The imbalanced carbon cycle increases CO2 in the atmosphere, suppressing H2O degassing and resulting in runaway warming and uninhabitable conditions. However, these results are somewhat sensitive to the deep hydrological water cycle, planetary hypsometry, and stellar luminosity evolution.

Our preliminary results have implications for the Habitable Zone inner edge and define a minimum threshold of surface water required to maintain a stable carbon cycle and, thus, a habitable planet. These findings could elucidate evolutionary processes on terrestrial exoplanets, as well as a climate transition from habitable to uninhabitable on Venus. 

Ula Jones Subsurface ocean formation on cold water-rich exoplanets: insights from a new ice Ih layer thermal model

Water-rich exoplanets, or exoplanets that may form with up to 1,000 times the water fraction of Earth, are thought to be relatively common in the universe. Because water is most likely a prerequisite for the origin and proliferation of life, these environments are considered promising candidates for the formation of extraterrestrial habitats. The development of a thermodynamically robust geophysical model, currently nonexistent, is necessary to explore the full diversity and complexity of possible hydrosphere structures in water-rich exoplanets (including subsurface ocean formation), and to make the most realistic possible predictions of interior structures based on known masses and radii. However, current methods for modeling the thermodynamic behavior of ice at high pressure are often ad hoc and inconsistent with experimental data, and furthermore, no steady state heat transfer model exists in agreement with the most up-to-date geodynamic numerical modeling. Therefore, we are developing a one dimensional heat transfer model for water rich exoplanet hydrospheres using holistic Gibbs energy equations of state for liquid water and ices Ih - VI, with a new framework for temperature variable thermal conductivity in outer icy shells. Preliminary results indicate that for for 10 wt% H2O Earth-mass planets with surface temperatures above roughly 200 Kelvin and heat fluxes above about 0.02 W/m2, subsurface ocean formation is consistently likely. At icy moon-like surface temperatures, necessary heat fluxes increase to 0.05 W/m2. Future work will introduce tidal heating and scaling laws for heat transport in high pressure ice, and derive a Gibbs energy equation of state for ice VII (which often makes up the majority of deep exoplanetary hydrospheres) that will be implemented in subsequent geophysical modeling.

Astrobiology & Planetary Science II

Kimberly Sinclair The Effect of Lipid Composition on Liposomal System Encapsulation Induced by Freeze-Thaw

In the origin of life, it is proposed that fatty acid vesicles could provide a comparmentalized environment for prebiotic molecules to concentrate and react. Many studies support the formation of fatty acid lipid vesicles as a potential primitive cell membrane. However, it is poorly understood how these simple vesicles evolved into a more complex protocell that can concentrate and isolate a mixture of prebiotic molecules to initiate complex systems. Understanding the role of lipid composition in encapsulation efficiency is significant for understanding the evolution of protocellular compartments. This study investigates the encapsulation of simple molecules (calcein) and more complex systems (in-vitro transcription of pepper RNA) within large unilamellar vesicles (LUVs) composed of PLPC, POPC, and DOPC phospholipids, subjected to freeze-thaw cycles. Encapsulation efficiency was evaluated in multiple buffer systems, with varying freeze/thaw conditions, over multiple cycles, and with varying lipid composition in order to optimize encapsulation. Our findings highlight the influence of lipid type on encapsulation and provide insight into the physicochemical dynamics underlying protocell evolution.

Autum Downey Nickel release during manganese oxide transformation: The role of lattice-bound vs. surface-adsorbed Ni in Mn oxide diagenesis in the deep ocean

Ni is an essential micronutrient for marine ecosystems, yet the processes governing its global cycling remain unresolved. Birnessite, a manganese oxide commonly found in marine sediments, is a key Mn-bearing phase that hosts Ni either as surface-adsorbed or incorporated into its crystal lattice. Over time, birnessite undergoes diagenetic transformation into todorokite, a more stable phase. Laboratory simulations of this transformation have shown that up to 50% of the surface-adsorbed Ni is released into solution. A critical, unresolved question is whether this transformation occurs rapidly enough to release Ni into seawater before sedimentation diminishes hydraulic conductivity with the overlying water column. This uncertainty arises from the fact that the in-situ kinetics of this process remain poorly constrained, largely due to the exceedingly long timescales of mineral transformation in natural settings. To address this, we simulate the process in the laboratory at elevated temperatures—accelerating the reaction—and then extrapolate the results to more realistic ocean-floor conditions (around 10 °C).

We transformed birnessite at 100°C and 75°C, pulling samples at regular intervals to extrapolate transformation rates as a function of temperature. In parallel, we performed two additional transformations using birnessite samples with differing Ni distributions: dominantly within the crystal lattice, and another dominantly adsorbed on the mineral surface. This approach allowed us to examine not only the temperature-dependent kinetics of the transformation but also how the location of Ni within the mineral structure affects its release during diagenesis. Our results show that the transformation rate at 75°C slowed by nearly 20-fold compared to 100°C. Interestingly, despite the slowed transformation kinetics, Ni concentrations released into solution were comparable to that of the 100°C transformation experiment. This suggests that Ni location within the crystal lattice likely plays a more significant role in Ni release than the bulk transformation rate. Collectively, these data demonstrate that Ni release into the water column is not directly proportional to the extent of birnessite transformation. These findings highlight the complex interplay between mineral transformation and Ni distribution within the crystal lattice, offering new insights into the timing and magnitude of Ni release in global marine systems.

Kunmanee Buphamanee  The Effect of Copper Availability on Nitrogen and Copper Isotope Fractionation by Denitrifying Bacteria: Implications for the Mesoproterozoic Greenhouse Effect Driven by N₂O Production via Incomplete Microbial Denitrification

The early Sun’s luminosity was theoretically too dim to sustain liquid water. However, its presence on Earth’s surface was likely supported by warming from the greenhouse effect. Nitrous oxide (N₂O) has been proposed as a greenhouse gas that could have contributed significant warming during the Mesoproterozoic Era (1.6 to 1.0 billion years ago), as the paleorecords of carbon dioxide and methane alone do not account for sufficient warming.

To address the lack of established paleo proxies for past nitrous oxide levels, this study investigates the coupled δ¹⁵N and δ⁶⁵Cu isotope values as proxies of a N₂O-rich atmosphere during the Mesoproterozoic Era by culturing denitrifying bacteria under varying copper availability. In sulfide-rich ocean conditions, copper precipitates as sulfide minerals, depleting copper in the water column. Given that copper is an essential metal for key metalloenzymes in denitrifying bacteria, our findings suggest that copper limitation led to incomplete microbial denitrification, resulting in excess nitrous oxide production. Preliminary δ15N analysis in denitrifying bacteria has been controlled by nitrate availability, a critical substrate for dissimilatory nitrate reduction in denitrification, and is independent of copper availability. While literature review suggests that heterotrophic bacteria preferentially incorporate light copper isotope intracellularly, the coupled δ¹⁵N and δ⁶⁵Cu proxies may help develop isotopic biosignatures for N2O-rich atmospheres and explore for similar past events in the geologic record, and potentially on other planets.

Gala Keynote Address

Dr. Carol Paty Ascent to Europa: A Journey to Jupiter's Ocean Moon

Beginning with Galileo Galilei in 1610, the Jovian system of worlds has inspired us and provided a rich environment for paradigm change and discovery. Nearly 415 years from Galileo's discovery of the Jovian moons, we are poised to explore mysteries of Europa.

NASA's Europa Clipper spacecraft launched in October 2024, with the goal of exploring Jupiter's moon Europa to understand its habitability. This robotic explorer will enter Jupiter orbit in April 2030, and, beginning March 2031, it will collect science data while flying past Europa 49 times. The mission will investigate Europa's habitability by studying its interior, composition, and geology, and will search for and characterize any current geologic activity including possible plumes. In this lecture, I'll discuss the mission's science objectives and how they will be addressed using an advanced suite of complementary remote sensing and in-situ instruments onboard Europa Clipper. From the short wavelengths of the ultraviolet to long wavelengths of radio, to a variety of compositional analysis techniques, to magnetic sounding of the interior, the diverse set of observations these instruments and investigations provide will paint a comprehensive picture of Europa's habitability and what lies beneath its frozen exterior.

Friday, April 4th

Structure, Petrology & Tectonics

Tamara Aranguiz Rago Exploring the Importance of Cenozoic Fault-driven Erosion in the Hyperarid Atacama using (U-Th)/He and AFT Cooling Histories from Coastal Cordillera Rocks

Mountain building and erosion in subduction zone settings are caused by complex feedback between tectonic forces and climatic conditions. To decode the contribution of these signals, we can employ apatite (AHe), zircon (ZHe) (U-Th)/He thermochronology, and Apatite Fission Tracks (AFT). These thermochronometers can quantify the cooling histories of rocks in mountain ranges, providing information about exhumation on the millions of years timescale.

The development of the Coastal Cordillera (CC) of Northern Chile provides a fascinating case study of structural and topographic building of the upper plate in an oblique subduction zone and the role of erosion in a setting of extreme aridity. This mountain range lies parallel to a sediment-lacking trench, immersed under persistent hyper-arid conditions since the Miocene, and cut through by the 1000-km length Atacama Fault System (AFS). This area has been studied by a few (U-Th)/He and fission track datasets that provide a regional thermal record from the Late Jurassic to Eocene. While the oldest dates correspond to an expected cooling period after plutonic emplacement, the mechanism that explains the younger, Eocene dates is still debated. Using a local, targeted sampling approach, my work explores the importance of fault-driven erosion in the Atacama’s hyperarid core using (U-Th)/He cooling histories from CC rocks. This work will present the preliminary results of thermochronological modeling from an area that might have transitioned from semi-arid to arid, and then to hyper-arid conditions, under continuous regional mountain building of the Andes and local faulting of the AFS. This unique context allows us to investigate a landscape that may archive either a pure history of strain or a complex interplay of tectonics with periods of increase in erosion rates. 

Anna Ledeczi Structure and properties of the Cascadia plate interface: evidence from a newly-described exhumed paleomegathrust in the Olympic subduction complex

The Olympic Subduction Complex (OSC) in the central Olympic Mountains is a deeply exhumed continuation of the offshore modern accretionary wedge of the Cascadia subduction zone. Metamorphic grade and thermochronology reveal that the OSC’s central core likely accreted by underplating at seismogenic depths. Duplexes of underplated sediments bounded above and below by abandoned paleomegathrust interfaces could therefore be preserved during exhumation. We characterize a previously unknown ~500 m wide belt of block-in-matrix mélange containing an anastomosing system of 9 major fault strands, which in turn include mm to cm wide discrete principal slip surfaces consistent with brittle-frictional, likely coseismic, slip. The lithologies are turbiditic sandstones and mudstones; other elements of ocean plate stratigraphy are absent. Raman spectroscopy of carbonaceous material refines peak paleotemperatures to 260-280°C, consistent with the seismogenic zone. We interpret these intermingled structures as a composite fault zone that records both slow and fast slip of the seismic cycle through coeval coseismic brittle-frictional and interseismic viscous deformation. We show that the mélange forms by cataclasis, pressure solution, and development and abandonment of localized shear surfaces, while the fault strands are dominated by concentrated cataclasis and brecciation. We calculate the degree of pressure solution experienced by the mélange at the thin section scale using scanning electron microscopy and compare the accumulated strain across the fault zone through anisotropy of magnetic susceptibility. We interpret this fault zone as an exhumed paleomegathrust interface, the first direct analog for the modern Cascadia subduction zone. The absence of basalt indicates that the megathrust fault was localized within the incoming plate stratigraphic sequence in the past, facilitating sediment underthrusting, similar to offshore structures observed via seismic reflection imaging in Cascadia and elsewhere today.

Winnie Fan Tracing crustal recycling in the Central American Volcanic arc using potassium isotopes

Recycling of crustal materials by subduction is one of the most important mechanisms producing chemical heterogeneities in the mantle. Arc magmas sample the most intensely subduction-influenced mantle wedge, and the geochemistry of arc magmas can shed light on the mechanism and flux of mass transfer between the subducting slab and the mantle wedge. Recycled crustal materials include subducting eroded forearc crust, sediment, altered oceanic crust (AOC), and other mafic and ultramafic slab components. An excellent location to study the relative importance of these components is the Central America Volcanic arc, owing to its striking along arc variation in subduction geometry, composition of overlying crust and subducting plate, as well as the geochemical characters of the arc magmas. 

Here, we report K isotopic compositions of a suite of arc lavas spanning from Guatemala to Costa Rica including basalts, basaltic andesites, and high-magnesian andesites. These samples display over 0.7‰ of variation in δ41K, comparable to arc lavas reported in literature. Most of them are isotopically heavier compared to MORBs and the normal mantle. Unlike trace element ratios and other isotope systems such as Li and Pb, the K isotopic composition does not show systematic along-arc variation. There is also no correlation of δ41K with MgO and K2O content, suggesting K isotopes are not fractionated by magmatic differentiation in these samples. In the Nicaragua samples, high δ41K is associated with high U/Th. By contrast, high δ41K is associated with low U/Th in the Costa Rican samples. This suggest that slab contribution in the form of fluid and melt can both drive heavy K enrichment in arc lavas. The Nicaragua and Costa Rica samples share an ambient mantle endmember that is isotopically heavier than depleted MORB mantle, suggesting that the mantle wedge was metasomatized by a common high δ41K component such as AOC-derived fluid. In summary, this study demonstrates that K isotope systematics are a powerful tracer for crustal recycling in arc magmatism. 

Nicole Aikin Making sense of migmatites: monazite petrochronology, k-means clustering and PCA reveal metamorphism, melt generation, and melt emplacement in the Upper Granite Gorge, Grand Canyon, USA

We combine standard in-situ monazite EMPA petrochronology methods with cluster and principal component analysis to evaluate complex internal rare earth and trace element zonation in a notoriously difficult-to-date restitic migmatite from the Grand Canyon’s metaturbitic Vishnu Schist. We present a new workflow for interrogating complex rare earth and trace element petrochronologic datasets in a more robust and statistical manner to uncover new insights for the host rock’s petrogenesis. This workflow preserves chemical and spatial relationships within multiply deformed and metamorphosed geochronologic phases, allowing for greater precision in data collection, facillitating extraction and interpretation of subtle variations in elemental concentrations This, in turn, enables identification of distinct age domains that *quantitatively* link monazite growth to specific mineral formation and breakdown reactions.

Upgoer 5s

Trent Thomas Ice Ball World

Nicole Aikin Party Rock!

Tamara Aranguiz Rago They know your age

To tell good stories about the world, we need to learn how old things are. This way, we can better understand the past and maybe the present. For people who study the land we live in, it is possible to learn the age of the land using a tiny little piece of rock that has an amazing memory. But what you do not know is that finding those little pieces can be really hard because you not only need to find them, you need to find the BEST ONES. In this talk, I will tell you about how it feels to spend hours trying to find those little pieces and how can you start losing your mind after glaring at them for weeks. 

Paul Morgan Land Slip Damn

Land Slip Damn, uh oh