2014 Gala

April 3-4, 2014

Keynote speaker: Donna L. Whitney (ESS '91)

Committee: Evelyn Conrado, Kelley Hall, Alicia Hotovec-Ellis, Kendra Pivaroff-Ward

Main website

Schedule

Thursday, April 3

9:00 - 9:05 - Opening Remarks (JHN-170)

9:05 - 9:50 - Session 1: Our Frozen Past: Snowball Earth and Ancient Ice (JHN-170)

• 9:05 Adam Campbell: Turning up the heat on Snowball Earth, how do sea glaciers respond to a warming climate?
• 9:20 Regina Carns: Sun, Salt, Snow: Modeling Surface Albedos on Snowball Planets
• 9:35 Lu Liu: Long-term stability of ancient ice buried in Beacon Valley, Antarctica

9:50 - 10:00 - Break

10:00 - 10:45 - Session 2: Evolving Ice: Glaciology Modeling (JHN-170)

• 10:00 Perry Spector: Testing ice-sheet models with cosmogenic nuclide measurements
• 10:15 Kristin Poinar: Evidence of meltwater refreezing at depth within the Greenland ice sheet
• 10:30 Max Stevens: The effect of climate changes on gas transport in polar firn

10:45 - 11:00 - Break

11:00 - 12:00 - Session 3: To Infinity and Beyond: Rockets and Remote Sensing of Mars (JHN-170)

• 11:00 Chad Truitt: Sample Return Systems for Extreme Environments
• 11:15 Ian Johnson: A Pulsed Plasma Thruster for Low-Pressure Atmospheric Operation
• 11:30 Carin Cornwall: Earth Analogs for Grain Characteristics of Mars Sediments
• 11:45 Frances Rivera-Hernández: A Radiative Transfer Approach to Reproducing the Optically Thin Dust Spectral Component in Mini-TES Observations of the Martian Surface

12:00 - 1:00 - Lunch

1:00 - 3:00 - Poster Session: Seismology, Geomorphology, Glaciology, and Lightning (JHN 100-level Hallway)

• Shelley Chestler: New families of low frequency earthquakes beneath the Olympic Peninsula, Washington
• Carl Ulberg: Distinct Nucleation and Propagation Phases of Northern Cascadia Episode Tremor and Slip Events
• Rebekah Cesmat: Locating the Seattle Fault in Bellevue, WA: Combining geomorphic indicators with borehole data
• Carrie Garrison-Laney: Relative sea-level rise in the last 1,000 years on Seattle fault uplifted block
• Habibah Hanan Mat Yusoff: Identifying possible active faults in Peninsular Malaysia using geomorphology analysis
• Karl Lang: Antecedence of Yarlung-Siang-Tsangpo River and Late Cenozoic exhumation of the eastern Himalayan Syntaxis
• Mike Hay: Modeling ice crystal fabric evolution
• Dan Kluskiewicz: Advanced Sonic Methods for Measuring Crystal Fabric in Ice Sheets
• Betzalel Massarano: Life on Snowball Earth: Channel Ice Flow and Thin-Ice Refugia
• Hao Zheng: Lightning VLF wavepropagation from source, through ionosphere to inner magnetosphere using WWLLN and Van Allen Probes

3:00 - 3:30 - Pre-seminar Snacks

3:30 - 4:30 - Colloquium: Donna Whitney, keynote speaker (JHN-075): The metamorphic rock record of slab interface dynamics, volatile cycling, and exhumation from the 'point of no return' in subduction zones

Friday, April 4

9:00 - 9:45 - Session 5: Keeping a Safe Distance: Volcanoes and Lightning (JHN-170)

• 9:00 Alicia Hotovec-Ellis: Changes in Seismic Velocity During the 2004 - 2008 Eruption of Mount St. Helens Volcano
• 9:15 Jillian Schleicher: Multiphase dynamics in magmatic mushes: Rábida Island, Galápagos
• 9:30 Michael Hutchins: Diurnal variation of the global electric circuit from clustered thunderstorms

9:45 - 10:00 - Break

10:00 - 10:45 - Session 6: Changing Landscapes: Surface Processes (JHN-170)

• 10:00 Shane Schoepfer: Penglaitan: An extremely high-resolution record o fthe latest Paleozoic from South China
• 10:15 Devin Bedard: Evaluating landslide triggers with sea level rise: The cause(s) and frequency of large, rotational/translational landslides in Puget Sound, Washington
• 10:30 Sarah Schanz: Strath terrace formation through internal forcing, West Fork Teanaway River, southeastern North Cascades, WA

10:45 - 11:00 - Break

11:00 - 12:00 - Session 7: Life Underground: Geomicrobiology and Paleontology (JHN-170)

• 11:00 Barbara Walker: Metabolic efficiency of Ammonia Oxidizing Archaea
• 11:15 Zoe Harrold: Effects of Baccillus subtilis endospore surface reactivity on the rate of forsterite dissolution
• 11:30 Meg Smith: Did Hydrogen Peroxide Play a Role in the Formation of Early Banded Iron Formations?
• 11:45 Margot Nelson: Placing a Platanistid in the Pacific Northwest

12:00 - 1:00 - Lunch

1:00-3:00 - Poster Session: Rocketry, Sedimentology, Paleoclimate, Paleontology, and Geomicrobiology (JHN 100-level Hallway)

• Paige Northway: Alternative Fuels for Pulsed Plasma Thrusters
• Nao Murakami: Preliminary Findings from the Development of High-Power Helicon Double Gun Thrusters with Future Application to Spacecraft Propulsion Systems
• Huang Vo: Zeppelin Motivation and Design for Testing of an Atmospheric Pulsed Plasma Thruster
• Heather Dawn Bervid: Investigation of Alpine Glacio-fluvial Deposition in the Northern Puget Lowland Using Indicator Minerals
• Katie Gauglitz: Tracing the Isotopic Fingerprint of airborne Lead Pollution in Northeastern Washington Lakes
• Andy Gault, Kristina Sumner, and Bart Weitering: Sediment Transport Concerns in Ohop Creek, Washington
• Landon Burgener: Soil Carbonates as Paleoclimate Proxies: A Clumped-Isotope Perspective
• Bret Buskirk: Geochemical Controls on Fossil Preservation in the Florissant Formation, Florissant Fossil Beds National Monument, Colorado
• Carina Edelman: Investigating the surface chemistry of forsterite weathered by bacillius subtilis endospores
• Chloe Hart: Mineral Surface Mediated Metabolism of Sulfolobus acidocaldarius

5:00 - 9:00 - Closing Ceremony (Vista Cafe, William H. Foege Building)

"Happy Hour" dinner and drinks, keynote speech, awards ceremony

Abstracts by Session

1. Our Frozen Past: Snowball Earth and Ancient Ice

Adam Campbell: Turning up the heat on Snowball Earth, how do sea glaciers respond to a warming climate?

• During the Neoproterozoic, the Earth’s oceans may have been completely covered with thick ice, during periods commonly called Snowball Earth events. The Snowball Earth environment would likely have prohibited the survival of photosynthetic eukaryotic algae, however, evidence has shown they persisted during these periods. Recent research, in attempt to reconcile this paradox, has demonstrated that narrow channels connected the ocean, called inland seas, may have provided refugia for photosynthetic eukaryotic algae during Snowball Earth events. Narrow channels would have restricted the flow of ocean-derived ice, diminishing ice penetration into a channel. Provided certain climate conditions and channel geometries, this diminished ice penetration would have allowed for either open water or thin sea ice, at the far end of a channel provided a sufficiently warm climate at the end of the channel. A channel with open water or thin sea ice would provide the conditions needed for the survival of photosynthetic eukaryotic algae.

It is possible that an invading sea glacier will override a potential refugium as it advances into an inland sea with a warmer atmospheric temperature than the ocean. Warmer ice is softer ice and flows more readily, however warmer atmospheric temperatures increase the rate of net sublimation at the sea glacier’s upper surface. These two effects compete, increasing and decreasing the penetration length of the sea glacier respectively. To test the possibility of a warming sea glacier overriding a potential refugium, I use a thermal evolution model coupled with an ice flow model to simulate sea-glacier flow as it advances into an inland sea with a non-uniform climate.

Here I find the flow rate of the sea glacier is slow enough that diffusion controls the thermal evolution of the sea glacier as it penetrates into a narrow channel. A diffusion controlled thermal evolution allows the softness of the ice to change more slowly than the net sublimation rate. Therefore the overall penetration of the sea glacier into the channel is diminished as it moves into a channel with a warming climate.

Regina Carns: Sun, Salt, Snow: Modeling Surface Albedos on Snowball Planets

• The large contrast between the reflectivity of the ocean and the reflectivity of ice makes any Earth-like planet with a large fraction of its surface covered in oceans susceptible to ice-albedo feedback. This phenomenon tends to enhance any change in the size of the planet’s ice caps, and under the right conditions can lead to the oceans freezing completely. Geological evidence suggests that Earth itself has experienced such planet-wide freezing during “Snowball Earth” episodes 600 to 800 million years ago.

The surface of these frozen-over oceans, so cold that liquid water would rarely make an appearance, might look rather different than ice surfaces on modern Earth. The intense sublimation on the equatorial regions of a Snowball planet would produce crusts of hydrated salt in regions whose ice formed from frozen seawater; in regions with ice formed from fallen snow, the sublimation would expose long-buried, super-dense snow and bubbly glacial ice. By modifying existing models of light interaction with modern Earth snow and sea ice, and approximating particles of salt and ice as spheres, we can estimate how much light these Snowball surfaces would reflect. This allows us to improve models of Snowball climates and helps determine how ice would wax and wane on Earth and other ocean-rich planets

Lu Liu: Long-term stability of ancient ice buried in Beacon Valley, Antarctica

• It is recognized that ground ice in the uppermost permafrost is widespread and may persist for very long times in hyper-arid, cold environments such as the McMurdo Dry Valleys of Antarctica and mid- and high-latitude regions on Mars. Ground ice is fundamentally important as a reservoir of water, proxy for paleoclimatic information, and a major component of the periglacial landscape; however, the primary controls on its depth below the surface, its long-term stability and age are still open questions. We are studying the long-term stability of ground ice in Beacon Valley, Antarctica that is believed to be buried after Taylor Glacier advanced into Beacon Valley. This ice is likely over 1 Ma old and simple vapor diffusion models suggest it should not be stable for such long periods. Our enhanced model on water vapor diffusion including the effect of recurring snow cover and snowmelt shows that ground ice at Beacon Valley is currently sublimating at a rate of 0.12 mm a-1 for the last 12 years. Here, we also present a study on the long-term stability of ground ice in Beacon Valley over the last 200 ka using Taylor Dome and Vostok ice-core records for temperature changes. Since ice loss is sensitive to changes in both temperature and relative humidity, the reconstructed temperature profile as well as the expected humidity changes with temperature employed for the first time are used in the vapor diffusion model. Given the environmental conditions and assuming the same snow cover and snowmelt conditions as present, the average ice loss rates for the last 200 ka is estimated to be 0.09 mm a-1. This is consistent with recent estimates of ice loss based on the abundance of cosmogenic nuclides in the Dry Valleys region (0.05 mm a-1). The slight difference of sublimation rates could be due to various changing factors such as ground ice depth, soil texture, porosity/tortuosity, and surface snow cover and snowmelt conditions.

2. Evolving Ice: Glaciology Modeling

Perry Spector: Testing ice-sheet models with cosmogenic nuclide measurements

• Projections of future changes of the cryosphere and sea level necessarily rest on ice-sheet models. Models that accurately simulate past ice-sheet changes are more likely to predict future changes. Bedrock cosmogenic nuclide concentrations are a function of the exposure and ice cover history that the bedrock has experienced. Transient ice-sheet models can therefore be used to predict bedrock cosmogenic nuclide concentrations. A compilation of bedrock Be-10 and Al-26 concentrations from Antarctica is presented, which serves as a continent-scale network of data with which models of the Antarctic ice sheet can be tested. A 5 Myr ice-sheet model is used as an example, and the data-model comparison highlights regions where the model performs well and regions where it performs poorly.

Kristin Poinar: Evidence of meltwater refreezing at depth within the Greenland ice sheet

• As the climate has warmed over the past decades, the amount of melt on the Greenland ice sheet has increased, and areas higher on the ice sheet have begun to experience melt regularly. We calculate how meltwater refreezing in firn (the densified snow that constitutes approximately the top 100 meters of the ice sheet) in the percolation and wet-snow zones (intermediate elevations) affects ice temperatures near Swiss Camp in the Pakitsoq area of western Greenland. By comparing our modeled temperature profiles to twentieth-century borehole data, we show that the ice column at Swiss Camp is warmer than refreezing in firn alone can account for. Therefore, we suppose that near-surface cryo-hydrologic warming, i.e. refreezing that is not confined to the firn pack but penetrates deeper into solid ice, is occurring in the top few hundred meters of ice at Swiss Camp, and possibly at higher elevations on the ice sheet. The recent and continuing increase in melt intensity and spatial extent suggests that this zone experiencing cryo-hydrologic warming, which enhances ice flow, will expand, making the ice sheet flow more quickly.

Max Stevens: The effect of climate changes on gas transport in polar firn

• Knowledge of the physics of firn-density evolution and gas transport in firn has several important applications in glaciology. These applications include making corrections for satellite-altimetry-based estimates of ice-sheet mass balance and determining the ice-age/gas-age difference for interpretations of ice-core records. The firn-physics group at the UW has been developing community models for firn-physical-properties (density, heat) evolution and for gas transport in firn. The models are modular, allowing the user to choose which physics to run, and the code is open source. A novel aspect of the models is that the gas model can be coupled to the density model, allowing the permeability of the firn to evolve transiently. This feature facilitates investigations of how changes in firn physical properties affect gas transport in firn and the mixing ratio of gasses trapped in bubbles. Here, we show preliminary model results of the effects of climate changes on gas transport in firn.

3. To Infinity and Beyond: Rockets and Remote Sensing of Mars

Chad Truitt: Sample Return Systems for Extreme Environments

• Since the Apollo era, sample return missions have been primarily limited to asteroid sampling due to high Delta V and vehicle mass constraints. More comprehensive sampling could yield critical information on the formation of the solar system and the potential of life beyond Earth. Hard landings at hypervelocity (1‐2 km/s) would enable sampling to several feet below the surface of penetration while minimizing the Delta V and mass requirements. Combined with tether technology, a host of potential targets becomes viable. In the following we detail the design, development and testing of a hard impact penetrator/sampler that can withstand the hard impact and enable the sample to be returned to orbit. Tether technology for release of the penetrator and capture of the return sample eliminates many of the restrictions that presently inhibit the development of sample return missions. We show through component testing and simulations that the proposed system can meet the requirements for the hard impact, and initial field testing shows that a full penetrator system can survive a subsonic impact intact. Testing during the summer of 2014 will evaluate the system’s performance during supersonic impacts. A full system design is presented and demonstrates that multiple return samples (either from different objects or from different areas from a small number of objects) of a few kg each is possible, with mass requirements that are only a fraction of what is required for the existing soft landing system that only return a few grams of surface material. Successful development of sample return capabilities will provide a major impetus for solar system exploration.

Ian Johnson: A Pulsed Plasma Thruster for Low-Pressure Atmospheric Operation

• A propulsion system capable of geostationary positioning for high-altitude (20km+), long duration airships is essential for telecommunication, weather observation, and surveillance operations. Operation at these altitudes prevents the use of most propulsion systems due to the unique background pressure regime. The pressure is too low for propeller devices and too high for traditional in-space thrusters. The inherent simplicity and robustness of the Pulsed Plasma Thruster (PPT), along with its ability to use the background atmosphere as an in-situ propellant makes it uniquely suited as a lightweight propulsion device for these airships. Laboratory measurements have shown the specific thrust of a PPT operating at atmospheric background pressures is proportional to the discharge chamber volume and pressure, inversely proportional to the capacitor discharge energy, and irrespective of the thrusters’ traditional fuel source. Current and voltage measurements suggest no difference to the electrical discharge between atmospheric and vacuum operation. While high-speed camera imaging shows the acceleration mechanism for atmospheric operation to be entirely electrothermal, compared to the hybrid electrothermal and electromagnetic acceleration at vacuum pressures. A high-altitude, long duration zeppelin test of the atmospheric PPT is scheduled for May of 2014.

Carin Cornwall: Earth Analogs for Grain Characteristics of Mars Sediments

• Sediments are characterized by composition, grain size and texture. Most sediment on Earth is composed predominantly of quartz, which is resistant to chemical and physical weathering. Mafic sediments, derived from volcanic deposits such as basalt, are significantly more susceptible to aqueous weathering and alteration. As a result, mafic grains readily break down on the Earth’s surface. On Mars, the surface is largely composed of mafic volcanic material and accumulations of wind blown sediments, derived from the volcanic material. Olivine, a prominent mafic mineral, is extremely susceptible to aqueous weathering but in the dry Martian environment, it may behave comparably to quartz, having a similar hardness and fracture pattern. Indeed, a few studies have identified many Martian dunes that are enriched in olivine.

Thermal inertia is a measurement of a material’s temperature change in response to external heating or cooling. It is the only thermal property that can be derived from remote sensing observations of planetary surfaces and used to investigate grain characteristics. It is equal to (k* ρ *c)1/2, where k is the thermal conductivity, ρ is the bulk density, and c is the specific heat capacity. Temperature data from satellite observations of the Martian surface are used to derive thermal inertia estimates and have been translated into grain sizes using an empirical formula based on laboratory experiments conducted at room temperature with spherical glass beads. Studies using this method suggest that Martian sediment is composed of predominantly coarse material, up to 1000μm in diameter. Under current atmospheric conditions, this would suggest that sediment deposition and migration occurs predominantly by traction but this contradicts many studies that have identified locations of active sand transport by saltation.

Thermal conductivity is the most variable component of thermal inertia and is dependent on grain texture, shape, composition, temperature and porosity of the sediment. Therefore, it is likely that grain sizes have been overestimated using the current method. This study uses samples of mafic sand from a variety of different locations and climates on Earth to better quantify Martian grain properties. Mafic sand samples from arid and wet climates will be compared and analyzed using a scanning electron microscope to determine the extent to which aqueous weathering influences grain texture, shape and mineralogy. Grain shape and size data will be collected and analyzed using a Particle Size Analysis System. Grain characteristics will then be incorporated into a thermophysical model and combined with remote sensing data to constrain grain size estimates of Martian sediments. Lastly, these results will be compared to previous studies using the empirical formula derived from spherical glass beads at room temperature.

The study of mafic sand composition, grain size and texture is important because it holds valuable information about sediment source, the amount of time grains spend in transport and details of how mafic minerals are weathered. In the absence of felsic material and fluvial agents, a better understanding of how mafic minerals are physically weathered on Mars is imperative for a more accurate interpretation of small-scale atmospheric circulation patterns, grain size estimates from thermophysical data, and potential details on a paleoclimate.

Frances Rivera-Hernández: A Radiative Transfer Approach to Reproducing the Optically Thin Dust Spectral Component in Mini-TES Observations of the Martian Surface

• The ubiquitous martian dust is one of the most common complicating factors in the acquisition and interpretation of thermal infrared spectroscopic measurements (TIR; ~200 to 2000 cm-1) from the martian surface. Observations made at the Mars Science Laboratory (MSL), Mars Exploration Rovers (MER), Viking, Phoenix, and Pathfinder landing sites have all shown dust coated surfaces and local changes attributed to aeolian dust deposition. Even with the use of a tool to remove surface dust deposits, as is done by the MSL and MER rovers, surfaces are not entirely clean and the interfering effects of dust are still present, even if also subdued. Dust is a component of remote sensing datasets of Mars that cannot be avoided.

Previous investigations have characterized the effects of dust in TIR spectral data sets. The effects attributed to atmospheric dust, and dust mantles on mirrors, rock and soil surfaces have been extensively studied. Although some of the effects of dust can complicate remote compositional determination, they are relatively well understood and simple to identify in TIR datasets. Recently however, an undocumented spectral contribution has been identified in many of the in-situ measurements of rocks and soils acquired by the Miniature Thermal Emission Spectrometer (Mini-TES) instruments on the MER.This spectral contribution is thought to be caused by thin mantles of dust (TMD; < ~10 μm). If not corrected, the additional contribution to the spectra caused by TMD can greatly hinder the mineralogical interpretation of rock surfaces. Although these effects have only been recently identified in Mini-TES data, they are likely to be present in TIR spectroscopic measurements of other Solar System bodies.

The focus of this study is the characterization of key radiative processes that are necessary to understand the source of the spectral features produced by TMD in Mini-TES observations. By combining laboratory measurements and radiative transfer modeling we attempt to reproduce and quantify the spectral features produced by TMD.

4. Poster Session: Seismology, Geomorphology, Glaciology, and Lightning

Shelley Chestler: New families of low frequency earthquakes beneath the Olympic Peninsula, Washington

• Following methodology similar to Bostock et al. [2012], we use waveform cross correlation to search for new families of low frequency earthquakes (LFEs) beneath the Olympic Peninsula, Washington. Using data from the Array of Arrays (AofA) and Cascadia Arrays for Earthscope (CAFÉ) experiments, our efforts have yielded dozens of new families scattered beneath the AofA stations, which add to the 9 known families from Sweet et al., [2012]. So far the timing and location of LFE activity corresponds with tremor during the 2010 and 2011 episodic tremor and slip (ETS) events. In particular, LFE activity reflects the along-strike migration of the slow slip rupture front. In addition, preliminary results show the potential to image propagation modes such as rapid tremor reversals (RTRs) and streaks in high resolution. Similar to Sweet et al., [2012] we observe that LFE activity is more vigorous during the onset of activity than during the ceasing of activity. We hope to use this observation to eventually quantify variations in slip rate during ETS and inter-ETS events.

Carl Ulberg: Distinct Nucleation and Propagation Phases of Northern Cascadia Episode Tremor and Slip Events

• Northern Cascadia episodic tremor and slip (ETS) events appear to have distinct nucleation and propagation phases. We find that there is a roughly linear increase in tremor amplitude over the first ~5 days of each ETS event. We observe a corresponding linear increase in the areal distribution of tremor. These episodes typically initiate down dip, and after approximately 5 days have organized and migrated to fill the up-dip/down-dip width of the tremorgenic zone. After this time, tremor amplitudes vary wildly, modulated by tidal stresses, as the tremor propagates along strike in one or both directions at roughly 8 km/day, continuing for 3-5 weeks. Inter-ETS tremor swarms can begin similarly to ETS events, but do not reach the maximum area and amplitude of ETS events, and instead die away in less than 5-10 days. Since the increase in tremor amplitude during the nucleation phase is proportional to the increase in tremoring area, the source amplitude per unit area is approximately constant, indicating a constant radiated energy rate per unit area associated with tremor.

In order to estimate tremor amplitude we use three-component seismograms from temporary deployments and permanent stations (Array of Arrays, CAFE, PNSN, TA) to estimate the amplitude of tremor bursts at the source location, using a method similar to Maeda and Obara (JGR, 2009). Source amplitude, or radiated energy rate, is proportional to the root-mean square of band limited (1.5-5.5 Hz) ground velocity for each 5-minute window. Station ground velocities and tremor locations, determined by a waveform envelope cross-correlation method (Wech and Creager, GRL, 2008), are inverted to obtain source amplitude and station statics, taking into account geometrical spreading and attenuation. The result is a catalog of source amplitudes for each of 40,000 tremor locations in northern Cascadia from 2006 to 2011.

Rebekah Cesmat: Locating the Seattle Fault in Bellevue, WA: Combining geomorphic indicators with borehole data

• Active crustal thrust faults can be difficult to study when surficial traces are either removed, masked, or don't exist. The Seattle Fault is an active east-west trending reverse fault zone that intersects both Seattle and Bellevue, two of the most populated cities in Washington. Rupture along strands of the fault poses a serious threat to infrastructure and thousands of people in the region. Precise locations of fault strands are still poorly constrained in Bellevue due to blind thrusting, urban development, and/or erosion. Seismic reflection and aeromagnetic surveys have shed light on structural geometries of the fault where it intersects bedrock (Liberty and Pratt, 2008; Blakely et al., 2001). However, the fault displaces both bedrock and unconsolidated glacial deposits; seismic data can be poor indicators of the location of fault strands within unconsolidated strata. In order to conduct an accurate assessment of fault outcrop, I interpret existing subsurface data sets and analyze surficial hillslope and channel morphologies to determine where the fault intersects bedrock and/or unconsolidated sediments. Geotechnical borings are used to look for potential fault offsets and to construct cross sections of the fault with Rockworks software. ArcGIS and LiDAR data are used in hillslope/channel geomorphology analysis. I attempt to determine if slip along the fault is recorded within hillslope/stream channel morphology. This study approaches the problem by combining techniques and data sets in order to locate strands of the fault that have not yet been identified.

Carrie Garrison-Laney: Relative sea-level rise in the last 1,000 years on Seattle fault uplifted block

• My research seeks to characterize a record of sea-level rise preserved in the sediments of a tidal marsh at the head of Hood Canal. The Lynch Cove marsh uplifted during the A.D. 900-930 Seattle fault earthquake, as part of the Seattle uplift between the Seattle and Tacoma fault zones. At Lynch Cove, uplift of at least 2 meters raised tide flats out of the intertidal zone. These uplifted flats became forested, and have since been submerged back into the intertidal zone by relative sea-level rise. Estimates of sea-level rise for south Puget Sound are ~1 meter in the last 1,000 years. This submergence is an ongoing process, as evidenced by fringes of dying trees at the high marsh-upland transition.

In outcrop, the environmental change from upland soil to intertidal marsh often appears as an abrupt (within 1 cm) change in sediment type, from a brown woody soil to a brownish-gray peaty mud. In some outcrops, the contact between upland and intertidal deposits is a less pronounced, though distinguishable, color and texture change. In addition, the southeast (seaward) edge of the Lynch Cove marsh contains two potential tsunami deposits. These layers are 2 cm thick gray sandy mud layers. One of these layers, based on correlation with nearby outcrops, dates between A.D. 1670-1780, a radiocarbon age from the colonizing marsh plant Triglochin maritima, and tree rings from a tree apparently killed when the forested area became submerged in tidal water. The other mud layer is older than A.D. 1700, but younger than A.D. 900-930, and awaits future dating. A sediment and diatom comparison of source area sediment from Hood Canal and the mud from these potential tsunami deposits is underway.

Diatom and foram paleoecology allows quantitative estimates of land-level changes for intertidal marsh sites through transfer function analysis. Preliminary diatom paleoecology supports the interpretation that the area the intertidal marsh now occupies was an upland, above the reaches of the highest tides, before it changed to an intertidal mid-marsh setting around A.D. 1700. Estimates of total vertical deformation will provide useful constraints for models of the tectonic setting, and local sea-level rise.

Can the sharp sediment contacts observed fit a time-transgressive sea-level rise model? Gradual sea-level rise alone may not be enough to accommodate the submergence observed, or the sediment contacts preserved. It is possible that there is an additional signal adding to the total submergence. Other possible sources of relative sea-level rise include isostatic adjustments of the uplifted horst, sediment compaction, or other tectonic event. The presence of a potential tsunami deposit and environmental change around the time of the A.D. 1700 Cascadia earthquake is intriguing.

Habibah Hanan Mat Yusoff: Identifying possible active faults in Peninsular Malaysia using geomorphology analysis

• In this project, I will compare river channel patterns, both in profile and in planform, of drainages that flow across mapped faults in Peninsular Malaysia. The purpose of this study is to evaluate the degree of fault-slip activity throughout the region. Peninsular Malaysia is a tropical country located ~300km to 600km from the seismically active Sumatra subduction zone. Despite this close proximity, Peninsular Malaysia is considered a tectonically stable terrain because of low seismic activity. Based on previous seismotectonic maps, most of the earthquakes are less than Mw 4 and concentrated in the southwest of Peninsular Malaysia, with exception to the Mw 3.8 Baling earthquake, which occurred in the northwest. Recent fault reactivation that is triggered by the active Sumatra subduction zone may have caused these earthquakes, but this hypothesis has been difficult to test due to overall rapid erosion rates and the small magnitude of the earthquakes. I will use open source digital elevation models (ASTER GDEM V2), along with previously published geologic and seismotectonic maps of Peninsular Malaysia to complete a regional GIS assessment. Fault activity will be assessed using fluvial and topographic metrics useful in identifying active structures. In particular, I expect to find knickpoints and overall steeper rivers as well as changes in hillslope and local relief near to active faults. This reconnaissance is a part of a larger project in Malaysia to incorporate geomorphic data with Southeast Asia active fault mapping in Earth Observatory of Singapore (EOS). The results of this work will be incorporated further with the Global Earthquake Model (GEM) for earthquake hazards.

Karl Lang: Antecedence of Yarlung-Siang-Tsangpo River and Late Cenozoic exhumation of the eastern Himalayan Syntaxis

• Late Cenozoic deformation of the easternmost margin of the Himalayan orogen dramatically modified the drainage patterns of the Yarlung-Tsangpo, Lohit and Irrawaddy river networks. Today, these distorted drainage basins reflect this accumulated strain, and proximal sedimentary basins record the time and sequence of distinct river capture and reversal events. We establish a sequential record of the reorganization of these river networks since 10-12 Ma using detrital zircon U-Pb provenance data from the eastern Himalayan foreland basin - demonstrating antecedence of the Yarlung-Siang-Tsangpo River during this time. We present new data from the most proximal areas of the basin, doubling the size of published basin U-Pb provenance data and completing the basin-wide sedimentary archive to discriminate between existing models of river reorganization. Specifically, we evaluate competing models disputing the capture of the Tibetan Yarlung-Tangpo river by a headward eroding Himalayan drainage as a mechanism to generate the Tsangpo Gorge, an enigmatic knickpoint dropping ~2 km through the eastern Himalaya. Our data show that such a Tibetan connection through the eastern Himalaya was present since the mid-late Miocene, favoring models of an antecedent Yarlung-Tsangpo river since “dragged” into a distorted configuration by active crustal-scale structures. Furthermore, the young (<30 Ma) anatectic zircons observed in modern river sediments to be exclusively derived from source rocks within the Tsangpo Gorge, are absent in the entire ~12-2 Ma proximal sedimentary record. This absence demonstrates that despite a long-lived Tibetan connection through the eastern Himalaya, surface exhumation of these source rocks did not occur until after ~2 Ma. Coupled detrital zircon fission-track dating of the same U-Pb samples further constrains the emergence of a young cooling age signal - presently attributed to rapid exhumation of the Tsangpo Gorge, emerging prior to 3.5 Ma, and potentially in the late Miocene. Our results suggest that glaciation and associated erosional processes active in the Quaternary may have played a substantial role in generating the anomalously steep local relief of the Tsangpo Gorge, but that rapid exhumation of the underlying Massif began much earlier, potentially in the Late Miocene. Our findings quantify the variability in sedimentary provenance data with proximity to source areas, highlighting the importance of a basin-wide dataset for the interpretation of river network reorganization. Beyond models of continental-scale drainage reorganization, our findings have significant implications for models relating surface erosion to upper crustal tectonic processes, and more broadly for the interpretation of distal basin sedimentary archives used for continental-scale climatic and tectonic reconstructions.

Mike Hay: Modeling ice crystal fabric evolution

• An individual ice crystal has strongly anisotropic plasticity, deforming much more easily in shear along the basal plane of the crystal than in other orientations. If grains in an ice polycrystal (as in an ice sheet) are randomly oriented, then the bulk response is isotropic. However, grains orient themselves in response to strain, creating a coupled system between ice fabric and ice flow. In addition, grain growth and recrystallization affects the fabric and thus ice flow.

Anisotropy in ice sheets can cause flow in directions other than the applied stress, and can induce folding and boudinage of ice layers. This complicates depth-age relationships important for paleoclimate interpretation from ice cores.

I am using a fabric evolution model I developed to analyze the interplay between deformation and fabric evolution. This looks at deformation and other physical processes to predict the evolution of the crystal fabric.

Dan Kluskiewicz: Advanced Sonic Methods for Measuring Crystal Fabric in Ice Sheets

• Crystal orientation fabric strongly influences the dynamics of ice sheets and is key to understanding the flow history of ice at polar sites where ice cores are collected. Sonic methods provide an important complement to more direct thin-section measurements of fabric in ice cores; they sacrifice some vertical domain-resolution for a greater sampling space and for measurement continuity. Previously employed strategies to infer crystal fabric from sonic wave speeds provide a one-parameter fabric description related to the vertical clustering of ice-crystal c-axes. This method is useful for studying fabric in ice that has a history of uniaxial vertical compression (as is common at ice domes) where crystal fabric is predominately azimuthally symmetric. Recent work at the WAIS Divide has demonstrated a need for new sonic methods to detect azimuthally asymmetric fabric that prevails in ice where the dominant stress is uniaxial extension. I will discuss sonic methods for measuring azimuthal fabric anisotropy, prospects for developing necessary technology for these methods, and demonstrate the necessity of these methods for future crystal fabric surveys at ice-core sites.

Betzalel Massarano: Life on Snowball Earth: Channel Ice Flow and Thin-Ice Refugia

• Little is known about the conditions that permitted photosynthetic life to survive the global glaciation events known as Snowball Earth events. During this time, sea glaciers covered the Earth’s oceans, prohibiting the transmission of light. Without liquid water and sunlight, where did photosynthetic life survive? Research has shown that under certain climatic conditions, areas of sufficiently thin ice, known as refugia, could have existed at the landward ends of narrow channels where sea glaciers would be unable to penetrate. The idealized channels used in sea-glacier flow models allow for refugia under a restrictive range of climate conditions. However, experiments varying the channel entrance width have shown that a less restrictive range of climate conditions are needed for the existence of these refugia than had been previously thought. I hypothesize that moderate variations in channel entrance and sidewall geometries could both 1) expand the range of climate conditions that allow for a refugium at the landward end of the sea glacier and 2) generate thin ice zones in additional locations within the channel, likely near the entrance and on leeward sides of promontories. Utilizing finite element modeling techniques to simulate rectangular, trapezoidal, and round-sided channel entrances and promontories I will determine the locations of regions of thin ice in idealized channels. Combined with reconstructions of real-world Neoproterozoic geomorphology, these results could help us understand the conditions under which photosynthetic life survived Snowball Earth and even help to locate evidence of Snowball Earth-era photosynthetic life on the modern Earth.

Hao Zheng: Lightning VLF wavepropagation from source, through ionosphere to inner magnetosphere using WWLLN and Van Allen Probes

• Lightning produces strong broadband radio waves, called "sferics", which propagate in the Earth-ionosphere waveguide and are detected thousands kilometers away from their source. Global real-time detection of lightning strokes including their time, location and energy, is conducted with the World Wide Lightning Location Network (WWLLN). In the ionosphere, these sferics couple into very low frequency (VLF) whistler waves which propagate obliquely to the Earth's magnetic field. Lightning generated VLF whistler dispersion in the ionosphere has been previously observed both from thunderstorm rockets and low altitude satellites. Previous studies also show a clear match and related attenuation between sferics detected by WWLLN and VLF whistlers observed by C/NOFS satellite. This global study can now be expanded to the magnetosphere using data from the Van Allen Probes (formerly known as the Radiation Belt Storm Probes (RBSP)) with high sampling rates for vector electric and magnetic fields, and extended altitude cover from ~600km to ~5 Re above the ground. In our work, we will show the one-to-one coincidence between WWLLN sferics and RBSP VLF whistlers. This talk will explore the relationship between these one to one lightning whistler waves with stimulated emissions such as lower hybrid waves, and possible energy deposition as the large amplitude lightning whistlers propagate into the outer magnetosphere.

5. Keeping a Safe Distance: Volcanoes and Lightning

Alicia Hotovec-Ellis: Changes in Seismic Velocity During the 2004 - 2008 Eruption of Mount St. Helens Volcano

• Mount St. Helens (MSH) effusively erupted in late 2004, following an 18-year quiescence. Many swarms of repeating earthquakes accompanied the extrusion and in some cases the waveforms from these earthquakes evolved slowly, possibly reflecting changes in the properties of the volcano that affect seismic wave propagation. We use coda-wave interferometry to quantify these changes in terms of small (usually <1%) changes in seismic velocity structure by determining how relatively condensed or stretched the coda is between two similar earthquakes. We then utilize several hundred distinct families of repeating earthquakes at once to create a continuous function of velocity change observed at any station in the seismic network. The high rate of earthquakes allows us to track these changes on a daily or even hourly time scale.

Following years of no seismic velocity changes larger than those due to climatic processes (tenths of a percent), we observed decreases in seismic velocity of >1% coincident with the onset of increased earthquake activity beginning September 23, 2004. These changes are largest near the dome of the volcano, and likely related to shallow deformation as magma first worked its way to the surface. Changes in velocity are often attributed to deformation, especially volumetric strain and the opening or closing of cracks, but also with nonlinear responses to ground shaking and fluid intrusion or saturation. We find strong correlation between velocity changes and real-time seismic amplitude (RSAM) during the first three weeks of activity, suggesting fluctuations of pressure in the shallow subsurface may have driven both seismicity and velocity change.

Jillian Schleicher: Multiphase dynamics in magmatic mushes: Rábida Island, Galápagos

• The behaviors of volcanic systems, including ocean islands, mid-ocean ridges, and arc magmatic systems, are controlled by conditions within their magma reservoirs. It is difficult to understand the dynamics that occur within these reservoirs, since they cannot be directly observed. However, conditions can be inferred based on the style of eruption. Volcanoes and fully crystallized plutons appear to have similar sources: magma reservoirs temporally and spatially dominated by crystal-rich states, called magmatic mushes. To explore the dynamics of mushes, we examine the relatively simple ocean island end-member of magmatic systems. Porphyritic basalt flows from ocean island volcanoes provide a snapshot of the magmatic mush prior to eruption.

The Galápagos Islands are a system of ocean islands with a range of eruption styles and deposits. We collected porphyritic basalt samples from Rábida Island, which contains deposits ranging in age from 0.7-1.0 Ma. Chemical zoning of anorthite content within phenocrysts indicates intermittent mixing occurs within the mush. This efficient mixing occurs despite high viscosities and crystal-fractions, with corresponding low-Reynolds number conditions. To explore mush-mixing dynamics, we present preliminary Eulerian-Lagrangian multiphase models using the fluids modeling software MFIX (Multiphase Flow with Interphase eXchanges). This computational fluid dynamics-discrete element method (CFD-DEM) monitors individual crystals and their interactions with the surrounding fluid, while also tracking the motion of inflowing fluid. We explore the dynamics of mush reintrusion events for a range of inflow velocities and fluid viscosities. We find that even at high viscosities and low velocities, efficient crystal and fluid mixing can occur.

Michael Hutchins: Diurnal variation of the global electric circuit from clustered thunderstorms

• The diurnal variation of the global electric circuit is investigated using the World Wide Lightning Location Network (WWLLN), which has been shown to identify nearly all thunderstorms (Jacobson 2006, using WWLLN data from 2005). To create an estimate of global electric circuit activity, a clustering algorithm is applied to the WWLLN dataset to identify global thunderstorms from 2010 - 2013. Annual, seasonal, and regional thunderstorm activity is investigated in this new WWLLN thunderstorm dataset in order to estimate the source behavior of the global electric circuit. Through the clustering algorithm, the total number of active thunderstorms are counted every 30 minutes creating a measure of the global electric circuit source function. The thunderstorm clusters are compared to precipitation radar data from the Tropical Rainfall Measurement Mission satellite and with case studies of thunderstorm evolution.

The clustering algorithm reveals an average of 660 ± 70 thunderstorms active at any given time with a peak-to-peak variation of 36%. The highest number of thunderstorms occurs in November (720 ± 90) and the lowest number occurs in January (610 ± 80). Thunderstorm cluster and electrified storm cloud activity are combined with thunderstorm overflight current measurements to estimate the global electric circuit thunderstorm contribution current to be 1090 ± 70 A with a variation of 24%. By utilizing the global coverage and high time resolution of WWLLN, the total active thunderstorm count and current is shown to be less than previous estimates based on compiled climatologies.

6. Changing Landscapes: Surface Processes

Shane Schoepfer: Penglaitan: An extremely high-resolution record o fthe latest Paleozoic from South China

• The Penglaitan section, in Guangxi, China, experienced extremely rapid sedimentation in the last two hundred thousand years of the Permian, making it likely the highest resolution record extant of marine conditions leading up to the end-Permian extinction. The Changhsingian (latest-Permian) section, exposed along the bank of the Hongshui River, is approximately 700 m. and shows major, rapid changes in water depth, depositional environment, and sediment composition, including a subaerial sequence, which is followed by approximately 60 m. of marine sedimentation before the main extinction horizon. This study focuses on this uppermost marine sequence, and uses rare earth and trace element geochemistry to identify intervals of intense volcanic input, which likely reflect early, rhyolitic eruptions associated with the Siberian Traps large igneous province. The numerous downstream effects of these eruptions in the marine realm include an increase in terrigenous sediment input, which likely reflects the devastation of terrestrial plant communities, and had possible ramifications for marine productivity, nutrient cycling and redox conditions. These downstream effects on marine biogeochemistry are assessed using a suite of trace element and isotopic tools.

Devin Bedard: Evaluating landslide triggers with sea level rise: The cause(s) and frequency of large, rotational/translational landslides in Puget Sound, Washington

• Hillslopes occupy a majority of the land surface including great rock cliffs on high mountain chains and extensive valley slopes in deep gorges in uplifted plateaus [1]. Hillslope instability is driven by meteorological and geologic processes, and landslides often occur in human environments. Hillslope stability is a balance of two physical processes or mechanisms: hydrologic, subsurface flow and stress, and the balance of these mechanisms governing hillslope stability is universal, from Puget Sound shoreline to highest Pacific Northwest peaks [2].

This proposed project investigates a deep-seated, rotational/translational landslide, known as the Ledgewood-Bonair Landslide, that occurred on the morning of March 27th 2013 and displaced 200,000 cubic yards (40,000 dump truck loads) of colluvium seaward along the westerly shoreline of central Whidbey Island. The prior histories and recurrence intervals of deep-seated landslides on Whidbey are not well-constrained. This project will provide a detailed study of the nature, underlying cause(s) and frequency (recurrence interval) of large, deep-seated landslides along the western shoreline of central Whidbey Island. Further comprehending the nature of the Ledgewood landslide requires knowing the triggering mechanism(s) and complex factors that control deep-seated landslide events such as: (1) surficial and underlying substrate geology, (2) drainage conditions and hydrology, and (3) shoreline erosion rates.

[1] Selby, MJ. Hillslope materials and processes. Oxford University Press, 1993.

[2] Lu, Ning and Godt, Jonathan. Hillslope Hydrology and Stability. Cambridge University Press, 2013.

Sarah Schanz: Strath terrace formation through internal forcing, West Fork Teanaway River, southeastern North Cascades, WA

• Bedrock (strath) terrace formation is generally thought to record external forcing due to climate, tectonic, or sediment supply changes, but evidence on the West Fork Teanaway River points to internal forcing mechanisms independent of climate or tectonic influences. The West Fork Teanaway River is located in the tectonically quiescent southeastern North Cascades, WA, and several terrace sets are present in a 3 km stretch of the river. To study the terrace-forming mechanism, we measured terrace heights using a total station, laser rangefinder, and hand level, and dated bedrock terrace surfaces using radiocarbon. We found terraces ranging in age from 40 C yr BP to 1810 C yr BP, with incision rates between 0.4 and 3.7 mm/yr, where incision rates are calculated by dividing terrace height above the low flow surface by the terrace age. Terraces range in height above the low-flow surface from less than 1 m to upwards of 5 m and show a stepped rather than smooth paleoprofile. The valley surface is mostly continuous, with anthropogenic disturbance in the lower 1 km of the study reach, and contains two distinct oxbow features that correlate with the lowest strath surface. Together with the step pattern, which indicates the terrace surfaces are unpaired and laterally discontinuous, this provides evidence for meander cutoff as a means of strath formation. The geometry of terraces in long profile is similar to models of meander cutoff generated by Finnegan and Dietrich (2011). A second explanation for strath formation comes from evidence of large valley-spanning log jams. Based on historical observations of valley-spanning jams 20 feet deep and 300 yards long that formed alluvial plugs and diverted the nearby Middle Fork Teanaway River, we hypothesize that jam-induced avulsions incised the streambed around the stable jam, forming discrete, small-scale strath terraces. As incision within the avulsed channel occurs, the stable jam protects a portion of the valley floor from incising. Log jams have been documented to remain stable in other rivers for up to 1400 years, which would create a stable strath 5 m above the active channel with the fastest observed incision rate of 3.7 mm/yr. Therefore we hypothesize that log jam induced avulsion and meander cutoffs can form strath terraces independent of an external driving mechanism, and suggest that this may be another explanation for strath terraces in forested regions.

7. Life Underground: Geomicrobiology and Paleontology (JHN-170)

Barbara Walker: Metabolic efficiency of Ammonia Oxidizing Archaea

• Nitrification in permanently nutrient deprived deep ocean regions is critical to our understanding of the global biogeochemical nitrogen cycle. Until recently ammonia oxidizing bacteria (AOB) were thought to be the primary nitrite producers in the environment; however, they cannot sustain nitrification in oligotrophic (nutrient deprived) environments. The recent discovery of a marine ammonia oxidizing archaea (AOA) Nitrosomonas maritimus (N. maritimus) able to sustain nitrification in oligotrophic conditions has suggested that N. maritimus-like AOA could be implicated in marine nitrification; however, the adaptations that allow N. maritimus to survive under nutrient poor conditions are unknown. Metabolic efficiency is one possible adaptation that might allow N. maritimus to subsist in environments below the nutrient threshold of AOB. Using calorimetry and biomass yield, we compared the metabolic efficiency of N. maritimus to AOB (Nitrosomonas europaea and Nitrosococcus oceani) to determine if significant differences in growth efficiency exist between these ammonia oxidizers. Ultimately understanding how AOA are able to contribute to nitrification in permanently nutrient-deprived ocean regions is critical to our understanding of the role Thaumarchaeota play in the global biogeochemical N cycle.

Zoe Harrold: Effects of Baccillus subtilis endospore surface reactivity on the rate of forsterite dissolution

• Primary mineral dissolution products, such as silica (Si), calcium (Ca) and magnesium (Mg), play an important role in numerous biologic and geochemical cycles including microbial metabolism, plant growth and secondary mineral precipitation. The flux of these and other dissolution products into the environment is largely controlled by the rate of primary silicate mineral dissolution. Bacteria, a ubiquitous component in water-rock systems, are known to facilitate mineral dissolution and may play a substantial role in determining the overall flux of dissolution products into the environment. Bacterial cell walls are complex and highly reactive organic surfaces that can affect mineral dissolution rates directly through microbe-mineral adsorption or indirectly by complexing dissolution products. The effect of bacterial surface adsorption on chemical weathering rates may even outweigh the influence of active processes in environments where a high proportion of cells are metabolically dormant or cell metabolism is slow. Complications associated with eliminating or accounting for ongoing metabolic processes in long-term dissolution studies have made it challenging to isolate the influence of cell wall interactions on mineral dissolution rates.

We utilized Bacillus subtilis endospores, a robust and metabolically dormant cell type, to isolate and quantify the effects of bacterial surface reactivity on forsterite (Mg2SiO4) dissolution rates. We measured the influence of both direct and indirect microbe-mineral interactions on forsterite dissolution. Indirect pathways were isolated using dialysis tubing to prevent mineral-microbe contact while allowing free exchange of dissolved mineral products and endospore-ion adsorption. Homogenous experimental assays allowed both direct microbe-mineral and indirect microbe-ion interactions to affect forsterite dissolution rates. Dissolution rates were calculated based on silica concentrations and zero-order dissolution kinetics. Additional analyses including Mg concentrations, microprobe and BET analyses support mineral dissolution rate calculations and stoichiometry considerations. All experimental assays containing endospores show increased forsterite dissolution rates relative to abiotic controls. Forsterite dissolution rates increased by approximately one order of magnitude in dialysis bound, biotic experiments relative to abiotic assays. Homogenous biotic assays exhibited a more complex dissolution rate profile that changes over time. All microbially mediated forsterite dissolution rates returned to abiotic control rates after 10 to 15 days of incubation. This shift in dissolution rate likely corresponds to maximum endospore surface adsorption capacity.

The Bacillus subtilis endospore surface serves as a first-order proxy for studying the effect of metabolizing microbe surfaces on silicate dissolution rates. Comparisons with published abiotic, microbial, and organic acid mediated forsterite dissolution rates will provide insight on the importance of bacterial surfaces in primary mineral dissolution processes.

Meg Smith: Did Hydrogen Peroxide Play a Role in the Formation of Early Banded Iron Formations?

• The origin of oxidized iron minerals in early banded iron formations (BIFs) remains a mystery. There are currently several theories about which process oxidized Fe(II) dissolved in the early ocean. Both abiotic and biotic mechanisms are among the theories, including the oxidation of Fe(II) by cyanobacterially-produced O2, the oxidation of Fe(II) by UV radiation, and the oxidation of Fe(II) by anaerobic phototrophic bacteria. Evidence supporting the role of these mechanisms in producing BIFs in the early Archean; however, is lacking. Here, we put another theory to the test: that Fe(II) was oxidized by hydrogen peroxide (H2O2) produced in the early Archean atmosphere. Our study is motivated by results from previous atmospheric models that show H2O2 would have been an important oxidant even in a reducing atmosphere. We use an updated photochemical model to calculate the rainout rate of H2O2 in the atmosphere at 3.8 Ga. We find that H2O2 rains out too slowly to account for iron oxidation at the scale required by large iron formations. Our results support the idea that iron oxidation in the early oceans was primarily the consequence of biologic processes. This work will be reported in the upcoming paper Pecoits et al (in preparation).

Margot Nelson: Placing a Platanistid in the Pacific Northwest

• The Miocene epoch represented a hotbed of cetacean evolution; during that time, whales underwent a large radiation of morphological forms and ecological specialization. The superfamily Platanistoidea experienced high diversity during this time, however, the Ganges River Dolphin is likely the one extant member of this once-large group. Here in Washington State, the University of Washington Burke Museum specimen 87105 is a single representative of this diverse clade. It is tentatively a member of the Squalodontidae, and shows morphological similarities, namely a thickened supraorbital ridge, with other members of the Platanistoidea seen in Oregon and in the Chesapeake bay. This project's goal is to research the distinguishing character traits of the Platanistoidea and its families. The aim is to place UWBM 87105 in a taxonomic group, into an evolutionary context, and into the biostratigraphy of the Northwest. The specimen's identity within the whale phylogeny will expand what we know about the cetaceans present in the Pacific Northwest during the Miocene. In addition, studying this specimen will shed light on the diversity of the Platanistoidea, diversity that is no longer present in the oceans today.

8. Poster Session: Rocketry, Sedimentology, Paleoclimate, Paleontology, and Geomicrobiology

Paige Northway: Alternative Fuels for Pulsed Plasma Thrusters

• Pulsed Plasma Thrusters (PPTs) constitute a robust and compact form of electric propulsion for space applications. Prime uses of PPTs include attitude control, station keeping, and de-orbiting maneuvers for small spacecraft and satellites. The typical solid fuel source for PPTs is Teflon (PTFE) due to its high specific impulse and low charring composition. The downside of Teflon propellant is the low total thrust output. In an effort to increase the thrust output from a PPT, a number of alternative propellant choices have been tested in the laboratory. A number of mineral and metallic propellant sources, available both here on Earth and in-situ in space, have resulted in improved thrust values. Results of the comparative performance of the alternative sources are presented.

Nao Murakami: Preliminary Findings from the Development of High-Power Helicon Double Gun Thrusters with Future Application to Spacecraft Propulsion Systems

• Human exploration and fast missions to the outer planets will require plasma thruster that can operate in the 100 kW to several MW power regime. Such power regimes can only be attained by increasing the size of the thruster, or by using an array of plasma thrusters. Because there are a variety of scale lengths and thermal issues involved in any plasma system, it is unclear which of the two yields the greatest efficiencies. The intent of the Double Gun thruster experiment is to examine whether an array of High-Power Helicon thrusters passing through a single large nozzle magnet downstream can lead to efficiencies greater than an individual system.

High-Power Helicon thruster is an electrode-less space propulsion system that uses a Nagoya type III helical antenna to create plasma, which is then accelerated by the magnetic field generated by series of Helmholtz coils. The High-Power Helicon Double Gun thruster builds up on the previous studies done in the Advanced Propulsion Laboratory by placing two helicon antennae side-by-side. Argon gas is used as a propellant. Each thruster is 43cm in length, and they are placed approximately 50 cm apart. Each thruster uses a Nagoya type III helical antenna, and is made from a quartz tube that is 12cm long. Three base field magnetic coils are placed around each helicon antenna to direct the plasma, and are 13cm in diameter. The magnetic nozzle is placed 10cm downstream from the base magnets to eject the plasma from the antenna, and is 25cm in diameter. The magnetic field of the base magnets and the magnetic nozzle for each thruster is oriented such that it is directed along the flow of the plasma. A large nozzle magnet is placed downstream of the Double Gun thruster system to direct the flow of the plasma. Each thruster is equipped with its own power supply, igniter, and gas puff system, allowing for fine calibration of the two thruster performance parameters. The power supply drives the antenna to a variable peak current at a frequency around 600kHz. A gas puff valve allows small amount of Argon gas to be puffed into a quartz tube. An igniter at the end of the gas puff system creates seed plasma. For the preliminary case presented in this abstract, the two thrusters are angled at approximately 15° towards each other. A Langmuir probe is placed 90cm downstream from the helicon antenna, and in between the two thrusters, in order to measure the plasma density. B-dot probes are placed in front of Right and Left Gun nozzles, and in between the two thrusters.

This poster will summarize the results obtained from preliminary data collection. The Langmuir probe data for the Double Gun thrusters firing simultaneously and the two thrusters firing individually will be presented, along with the pictures of the Double Gun thrusters firing. Also, data at various spatial locations downstream of the two thrusters will be presented to characterize the behavior of the Double Gun thrusters’ exhaust plasma flow.

Huang Vo: Zeppelin Motivation and Design for Testing of an Atmospheric Pulsed Plasma Thruster

• The Advanced Propulsion Lab from the Earth and Space Sciences Department has developed a Pulsed Plasma Thruster (PPT) which utilizes a propulsion system ideal for operating in a low pressure and high altitude environment. In order to test the PPT, a high-altitude balloon flight will be carried out by the lab at the end of May 2014. The structure housing the thruster is a zeppelin- type aircraft composed of two lifting balloons, a primary zeppelin balloon, and a supporting frame for the thruster; it is currently in the process of being de- signed and tested. There are several constraints that need to be fulfilled by the aircraft. The zeppelin frame needs to be strong and durable enough to support the thruster, while still light enough so that it could be lifted and fulfill the 12 lbs weight compliance from the Federal Aviation Administration. In addition, the zeppelin needs to be able to raise the payload above the jet stream to an altitude of approximately 70,000 feet and maintain that height once reached. To achieve this, the structure uses two 800-g high altitude latex balloons with 150 cubic feet of helium providing the lifting force. Once the optimal height is reached, the two lifting balloons will be separated from the main structure through the uses of NiChrome wire and the primary zeppelin balloon will take over, providing neutral buoyancy at the desired location in order for the thrust of the PPT to be measured accurately. The main core of zeppelin will be fabri- cated in house with mylar as the primary material for the balloon and carbon fiber rod for the supporting frame. Current calculations estimate the size of the zeppelin to be 45 feet in length with a 4.5 feet radius. There are several issues the zeppelin is currently facing such as the fragility of the material used, the expansion of the helium at high altitude, the weight of the payload, and just the sheer size of the aircraft.

Heather Dawn Bervid: Investigation of Alpine Glacio-fluvial Deposition in the Northern Puget Lowland Using Indicator Minerals

• During the last glaciation (18,000–13,000 years ago) a lobe of the Cordilleran Ice Sheet advanced into the Puget Lowland, scouring and sculpting the previous landscape into the present-day topography. Prior to the Puget Lobe’s advance, Cascadian alpine glacial systems had reached their maximum extent and were depositing large volumes of sediment into the Puget Lowland basin. While the extensive glacio-fluvial deposits that are preserved in the Puget Lowland indicate a thick sequence of sediment had filled the basin prior to the Puget Lobe’s advance, there has been no previous research on the source (or provenance) of these sediments. Much of this outwash sediment is currently attributed to the Puget Lobe, although a significant volume was likely deposited by Cascadian glacier sources prior to the Puget Lobe’s advance. Samples collected from glacio-fluvial sediment and Puget Lobe till at bluff exposures on Whidbey Island, as well as alluvium collected in present-day Cascadian river drainages (a proxy for paleo-Cascadian glacio-fluvial outwash) can be used to obtain a modal analysis of the basin fill. This analysis uses an electron microprobe to evaluate the proportional occurrence of source-indicative minerals in order to determine the provenance of Puget Lowland sediments. The expected results are for indicator minerals present in the Cascadian drainage sediments, e.g., garnets, to occur in higher concentrations than in the Puget Lobe sediments due to source bedrock composition. For example, the result of high garnet (or other indicator mineral) content in the Lowland sediments would indicate that the sediment was deposited by Cascadian glacio-fluvial source rather than by the Puget Lobe, redefining which depositional units are attributed to each source. Knowing the relative volumes of sediment deposited by these two sources could allow for calculations of alpine versus continental glacier sedimentation rates in the region during the last glacial maximum.

Katie Gauglitz: Tracing the Isotopic Fingerprint of airborne Lead Pollution in Northeastern Washington Lakes

• Heavy metal pollution from a smelter in Trail, British Columbia may be a source of anthropogenic Pb contamination in northeastern Washington lakes. This smelter, located near the Canadian border, has been operating since 1895. It dumps slag – waste created during smelting – into the Columbia River, and emits metals into the atmosphere via smokestacks. We analyzed sediment samples from lakes in northeastern Washington to determine the source of anthropogenic Pb. Determining whether smelter Pb travels via airways and contaminates the environment is a critical health issue. We measured Pb isotope ratios of lake sediments on a multiple-collector inductively coupled plasma mass spectrometer, following acid dissolution of the samples and separation of the Pb.

Lead isotope ratios provide a tool to trace anthropogenic Pb. Pb206, Pb207, and Pb208 are daughter products of U238, U235, and Th232, respectively. Pb204 is not produced by radioactive decay. Each parent isotope has a different half-life, so different geological sources have different relative amounts of each Pb isotope. This gives every Pb source its own Pb isotope fingerprint. No natural processes alter the fingerprint of a Pb source after industrial processing. Therefore, we can test for smelter emissions in lake sediments.

Lake sediments contain natural and anthropogenic Pb. In Pb207/204 vs. Pb206/204 space, Pb from slag samples has relatively low values, with Pb206/204 ratios from 16.7-17.4. Natural Cascade Pb has much higher isotopic ratios with Pb206/204 ratios of 18.5-19.0. Lake sediment Pb covers most of this range, with Pb206/204 ratios from 17.02-18.32.

All analyzed samples contain significant anthropogenic Pb. Lakes closer to the smelter generally show higher contributions of anthropogenic Pb concentrations. Additionally, the gradation in anthropogenic Pb contamination forms a pattern expected from prevailing winds transporting smelter emissions. The Pb isotope data provide strong evidence for airborne Pb contamination of some Washington lakes from the Trail, B.C. smelter.

Andy Gault, Kristina Sumner, and Bart Weitering: Sediment Transport Concerns in Ohop Creek, Washington

• Ohop Creek, located in the Ohop Valley of Washington State, is a tributary to the Nisqually River. Ohop Creek has undergone significant changes over the past century. In the early 1900’s the meandering creek was straight ditched to dry out the valley floor for agriculture, which severely damaged the salmon habitat along the reach. Recent developments in Ohop Creek have attempted to restore the straight ditched portions of creek to its original meandering state, which should also result in restored salmon runs through the creek. One apparent side effect of changing the creek’s course is that it changed the hydraulics of the creek and its sediment transport capabilities. Currently there is no natural gravel found at the Ohop Creek restoration site; however, there is a substantial gravel source upstream of the restoration site. Gravel is prevalent along the Ohop Creek system, but disappears 0.60 miles upstream. Our team is investigating the channel hydraulics and carrying capabilities of Ohop Creek to determine why gravel is not continuing further down into the restoration area.

Landon Burgener: Soil Carbonates as Paleoclimate Proxies: A Clumped-Isotope Perspective

• Soil carbonates are a paleoclimate proxy that can provide critical insight into terrestrial climate change. Although many previous studies have used pedogenic carbonates to reconstruct paleoclimate conditions, these efforts have been limited by uncertainties regarding the relationship between the conditions recorded by the carbonate and air temperature. Peters et al. (2013) showed that soil carbonate formation temperatures do not always correspond to warmest annual air temperatures, and proposed that the timing of the wet-season may control the seasonality of carbonate growth. In order to test this hypothesis, this study presents carbonate clumped-isotope thermometry (CIT) data for a suite of soil carbonate samples collected from a >4 km elevation transect in the Elqui Valley in north-central Chile, which receives 70% of its annual precipitation during the winter season at all elevations. The CIT method directly calculates the formation temperature of carbonates by measuring the abundance of carbonate molecules with “heavy” 13C-18O bonds, avoiding the complications of the conventional water-carbonate oxygen isotope thermometry method. Reconstructed formation temperatures for low-elevation (<3000 m) samples agree with observed summer soil temperatures; however, there is an abrupt change to cooler temperatures for the high-elevation (>3000 m) samples. This discrepancy in temperatures may be caused by several different factors: differences in the sample ages; elevation-related effects such as the timing of snowmelt at high elevations; or differences in the soil substrate at different sample locations. These findings suggest that in mountainous regions the relationship between carbonate formation temperature and air temperature may be complicated by a host of factors, and that caution should be exercised when using such samples to reconstruct local paleoclimate conditions.

Bret Buskirk: Geochemical Controls on Fossil Preservation in the Florissant Formation, Florissant Fossil Beds National Monument, Colorado

• The Late Eocene freshwater Florissant Formation can be described as a lagerstatten locality due to the reported excellent and unique preservation, and high diversity, of its flora and fauna. The fossils are preserved within the formation’s lacustrine and fluvial shales and mudstones and in pumice and ash conglomerates originated from the Thirtynine Mile volcanic field. Preservation in the shales of the paleontological material has been attributed to a sedimentation cycle in which clay and ash alternate with diatomaceous algal mats. Recently, other studies on the taphonomy of the carbonized botanical and entomological impressions have demonstrated that excellent preservation of specimens is rarely observed. The preservation quality instead is ranked as fair or poor in most cases, leaving doubt as to how well the shales and other lithologies truly preserve the fossils. In addition to the botanical and entomological specimens, recent detailed, stratigraphically-controlled field studies have shown that gastropods and bivalves occurred throughout the lake’s duration and are preserved within its different lithologies. However, original shell-calcite is only recorded in fossils from a single horizon of conglomerate, and in other stratigraphic horizons they are only observed as casts and molds or the shells have been entirely replaced by silica. In an effort to elucidate the mechanisms of preservation recorded within these lithologies, analyses of the biogenic calcites of these invertebrates have been completed. Electron microprobe and cathodoluminescence microscopy of thin sections from both the calcitic shells and their surrounding lithologies were used to describe their mineralogies. For comparison, bulk sample mineralogy was obtained through X-Ray diffraction analysis. These analyses have shown that the geochemical drivers of preservation within the paleolacustrine system influenced a chemical gradient that drove carbonate dissolution during the lake’s existence. This system controlled the amount of carbon (calcite shells or impressions) that was preserved in the lake’s associated deposits. Unraveling the geochemical drivers of preservation within the Florissant lake system furthers our understanding of depositional environments and their potential to preserve paleontological material.

Carina Edelman: Investigating the surface chemistry of forsterite weathered by bacillius subtilis endospores

• Products of silicate mineral dissolution play important roles in a variety of geochemical cycles and biologic processes. Calcium and magnesium released during silicate weathering can precipitate as carbonates resulting in the removal of CO2 from the atmosphere and, over geologic timescales, plays an important role in the carbon cycle and global climate. Dissolved potassium and iron reach the ocean and support primary productivity. Understanding the mechanisms and stoichiometry of silicate weathering are therefore important in relating weathering rates to global ion budget.

In abiotic systems, silicate dissolution often begins as a non-stoichiometric reaction dependent on solution pH. In acidic versus alkaline solutions, forsterite leaches cations and silica, respectively, resulting in a surface enriched with the counter ion. Microbes are, however, ubiquitous in water-rock systems where active silicate weathering occurs. Recent evidence shows a dramatic increase in forsterite (Mg2SiO4) dissolution rate that correlates with the presence of dormant bacterial endospores. The mechanisms driving enhanced dissolution in the presence of a complex organic surface and its effect on mineral surface chemistry is, however, unknown.

We investigate the effects of Bacillus subtilis endospore enhanced dissolution on the surface chemistry of forsterite grains using Attenuated Total Reflectance- Fourier Transform Infra-red (ATR-FTIR) spectroscopy. ATR-FTIR is a technique that measures mid (MIR) to far (FIR) infrared absorption of a sample over a shallow penetration depth. Forsterite (Fo90, Mg1.8Fe0.2SiO4) powder was incubated with B. subtilis endospores for 40-80 days at pH ~ 7.5 under oxidizing conditions. We compare MIR and FIR ATR-FTIR spectra of un-reacted forsterite, abiotically reacted controls, and biotically weathered forsterite to determine how the surface has changed from the weathering processes. MIR and FIR ATR-FTIR spectral scans of forsterite grains incubated with endospores display peak shifts relative to the controls. Small amounts of Fe (II) present in the forsterite likely precipitated as iron oxide coatings on the mineral and endospore surfaces. Variations in FIR peaks may indicate the presence of iron oxides. Results from this research will advance our understanding of how bacterial surfaces affect chemical weathering in the environment.

Chloe Hart: Mineral Surface Mediated Metabolism of Sulfolobus acidocaldarius

• Sulfolobus is a unique genus of archaea that contains thermoacidophilic species, flourishing optimally in acidic pools and springs with a pH of 2-3 and temperatures at 70-80°C. It was originally thought surface adherence was required for microorganisms to obtain energy through the oxidation of elemental sulfur. However, it is now known this is not the case for Sulfolobus. Previous work illustrated that Sulfolobus grew both attached and unattached to sulfur when grown heterotrophically. However, previous work did not address spatial preference. The focus of this study is to observe the heterotrophic metabolic activity of Sulfolobus acidocaldarius (S. acidocaldarius) in two different conditions to determine preferential growth: 1) an environment where direct attachment is permitted and microorganisms are free in solution with sulfur crystals, and 2) an environment where a semi-permeable barrier prevents direct attachment to sulfur crystals, but allows dissolved ions to interact. The goal is to determine which condition yields the most efficient growth, where efficiency is determined by biomass yield on the substrate (electron donor). It is hypothesized that although direct contact is not required, adherence to sulfur will yield the greater more efficient growth. S. acidocaldarius will be grown heterotrophically in sealed septum vials in Brock’s basal salts medium1, 2, with trace elements and glucose, held at 70°C. Two experimental conditions will be tested deemed “detached” and “free”. In the detached experiments, sulfur crystals will be placed in dialysis tubing and suspended into solution with S. acidocaldarius to prevent attachment on the sulfur crystals but allow aqueous ions to interact. In the free experiments, S. acidocaldarius will be able to directly interact with sulfur crystals and allowed to attach. After approximately 7-10 days the carbon dioxide will be measured using a carbon dioxide meter, sulfate will be measured with anion chromatography, and the final biomass of S. acidocaldarius will be determined by a microscopic cell counts as well as the weight of the final dried biomass on pre-weighed filter paper. The biomass yield, in C-mol biomass based on the average composition of microbial biomass, on the glucose substrate will be calculated and used to compare growth under the two experimental conditions with more efficient growth on glucose resulting in a larger biomass yield.