Physical Sciences and Mathematics Commons^™

Phillipsite And Al-Tobermorite Mineral Cements Produced Through Low-Temperature Water-Rock Reactions In Roman Marine Concrete, Marie D. Jackson, Sean R. Mulcahy, Heng Chen, Yao Li, Qinfei Li, Piergiulio Cappelletti, Hans-Rudolf Wenk

Geology Faculty Publications

Pozzolanic reaction of volcanic ash with hydrated lime is thought to dominate the cementing fabric and durability of 2000-year-old Roman harbor concrete. Pliny the Elder, however, in first century CE emphasized rock-like cementitious processes involving volcanic ash (pulvis) “that as soon as it comes into contact with the waves of the sea and is submerged becomes a single stone mass (fierem unum lapidem), impregnable to the waves and every day stronger” (Naturalis Historia 35.166). Pozzolanic crystallization of Al-tobermorite, a rare, hydrothermal, calcium-silicate-hydrate mineral with cation exchange capabilities, has been previously recognized in relict lime clasts …

Recreating Intercalated Clays Of Chondritic Meteorites, Katherine Winchell

Scholars Week

In order to better understand the reactions that form intercalated clays in carbonaceous chondritic (CC) meteorites, a suite of six combinations of nontronite plus fine-grained metal, organics, or sulfur ± water were heated at a temperature of 200°C in sealed Parr bomb containers for a period of three months. Intercalation is the process of materials being introduced between the layers of expandable clays via cation exchange. Reflectance spectra of CC meteorites differ from those of mixtures of the end members made physically in that the CC spectra are darker and show extremely subdued absorption bands of the phyllosilicates (clays) that …

Analysis Of Concentric Growth Rings In Hydrothermal Epidote, Brandi Petryk

Scholars Week

Crystals found within geothermal cores from Akutan Island, Alaska, show concentric growth rings of what appear to be alternating bands of epidote and clinozoisite minerals. The intent of this project is to determine the nature of these growth rings and what processes could allow them to form. Our working hypothesis is that the rings are due to fluctuations in the oxidation states of the hydrothermal system, which would control the amount of available Fe3+ needed to make epidote. In relatively reducing conditions, Fe3+ would be scarce and clinozoisite (Fe-poor variety of epidote) would form. We have tested this hypothesis by …

Explosive Processes During The 2015 Eruption Of Axial Seamount, As Recorded By Seafloor Hydrophones, Jacqueline Caplan-Auerbach, R. P. Dziak, J. Haxel, D. R. Bohnenstiehl, C. Garcia

Geology Faculty Publications

Following the installation of the Ocean Observatories Initiative cabled array, the 2015 eruption of Axial Seamount, Juan de Fuca ridge, became the first submarine eruption to be captured in real time by seafloor seismic and acoustic instruments. This eruption also marked the first instance where the entire eruption cycle of a submarine volcano, from the previous eruption in 2011 to the end of the month-long 2015 event, was monitored continuously using autonomous ocean bottom hydrophones. Impulsive sounds associated with explosive lava-water interactions are identified within hydrophone records during both eruptions. Explosions within the caldera are acoustically distinguishable from those occurring …

Phillipsite And Al-Tobermorite Mineral Cements Produced Through Low-Temperature Water-Rock Reactions In Roman Marine Concrete, Sean R. Mulcahy, Marie D. Jackson, Heng Chen, Yao Li, Piergiulio Cappelletti, Hans-Rudolf Wenk

Geology Faculty Publications

Pozzolanic reaction of volcanic ash with hydrated lime is thought to dominate the cementing fabric and durability of 2000-year-old Roman harbor concrete. Pliny the Elder, however, in first century CE emphasized rock-like cementitious processes involving volcanic ash (pulvis) “that as soon as it comes into contact with the waves of the sea and is submerged becomes a single stone mass (fierem unum lapidem), impregnable to the waves and every day stronger” (Naturalis Historia 35.166). Pozzolanic crystallization of Al-tobermorite, a rare, hydrothermal, calcium-silicate-hydrate mineral with cation exchange capabilities, has been previously recognized in relict lime clasts of the concrete. Synchrotron-based X-ray …

Ongoing Exhumation And Recent Exposure Of Sedimentary Outcrops On Mars, Joshua M. Williams

WWU Graduate School Collection

Determining the habitability of ancient environments on Mars and their biosignature preservation potential is a primary goal of all recent Mars exploration missions. Because cosmogenic radiation destroys organic biosignatures at the Martian surface, freshly-exposed outcrops that have been previously protected by overburden provide potential sites where organic biosignatures could be observed. Scarp retreat is one common mechanism for exposing fresh outcrop surfaces. The absence of liquid water on Mars leaves aeolian processes to be the dominant eroding agent, and aeolian erosion drives scarp retreat by undercutting erosion-resistant cap rock that fails and breaks off from outcrops. This continual action creates …

Building Arc Crust – Plutonic To Volcanic Connections In An Extensional Island Arc, The Alisitos Arc Crustal Section (Southern Rosario Segment), Baja California, Rebecca A. (Rebecca Anne) Morris

WWU Graduate School Collection

The southern volcano-bounded basin of the Rosario segment of the Cretaceous Alisitos oceanic arc provides outstanding 3-D exposures of the upper 7 km of an extensional arc, where crustal generation processes are recorded in the upper crustal volcanic rocks and underlying plutonic rocks. These exceptional exposures allow for the study of the physical and chemical links between the rock units, and helps constrain the differentiation processes active during the growth and evolution of the arc.

Upper crustal volcanic rocks comprise a 3-5 km thick volcanic-volcaniclastic stratigraphy with shallow sill and dike intrusions. Coarse-grained plutonic rocks intrude these units over a …

Seismicity And Velocity Structure Of Offshore Hawai`I, Including Lo`Ihi Submarine Volcano, Dara K. Merz

WWU Graduate School Collection

This study presents the earthquake data collected from a nine month deployment (September 2010 - June 2011) of a temporary ocean bottom seismometer (OBS) network fully surrounding Lo‘ihi submarine volcano, Hawai‘i. This allowed us to widen the aperture of earthquake detection around the Big Island, lower the magnitude detection threshold, and better constrain the hypocentral depths of offshore seismicity that occurs between the OBS network and the Hawaiian Volcano Observatory (HVO) land based network. Although this deployment occurred during a time of volcanic quiescence for Lo‘ihi, it establishes an important basis for background seismicity of the volcano. 463 earthquakes were …

Structural Evolution Of The San Juan Thrust System, Orcas And Shaw Islands, Wa, Kevin Quillan

WWU Graduate School Collection

The San Juan Thrust System represents the western elements of the Cascades orogen and preserves evidence for Cretaceous Cordilleran margin tectonics. The kinematics of deformation phases and their temporal relationship to accretionary wedge high-pressure low-temperature metamorphism remains uncertain. The structural and metamorphic evolution of the San Juan Thrust System was studied on Orcas and Shaw Islands in Western Washington. Detailed field mapping indicates that a widespread S1 flattening fabric (formed during D1) is subparallel to and cut by an S2 fabric found within brittle-ductile shear zones that bound the terranes (formed during D2). Post-cleavage brittle structures (formed during D3) offset …

Gender Stereotype And Spatial Reasoning: The Milankovitch Cycles, Kristina Gustovich

WWU Graduate School Collection

Stereotype threat, a phenomenon in which learners feel at risk of confirming negative stereotypes about their abilities, is often associated with spatial reasoning abilities in geoscience and has a disproportionately negative effect on women. This study examines how students’ growth or fixed mindsets mediate or amplify the effects of stereotype threat regarding self-perception of their spatial skills and learning how Earth’s cyclical orbital geometry influences its climate.

Undergraduate, introductory-level Geology students at Western Washington University were given a Pre-Test and Post-Test, a spatial reasoning test, and an assessment of their spatial reasoning abilities. Of the 154 participants, 41 had a …

Initiation And Evolution Of Subduction: T-T-D History Of The Easton Metamorphic Suite, Northwest Washington State, Jeremy Cordova

WWU Graduate School Collection

In the Northwest Cascades, results from previous workers show the Easton Metamorphic Suite contains an inverted metamorphic sequence with ultramafic rocks underlain by amphibolite and high-temperature blueschist that are juxtaposed above high-pressure low-temperature Shuksan Greenschist and Darrington Phyllite. In this study, amphibole and white mica ⁴⁰Ar/³⁹Ar geochronology is combined with cation exchange thermometry to constrain the temperature-time-deformation history of the suite. Amphibolite facies fabrics record two deformation events at 10 kbar. The oldest fabric formed at ~760 ̊C prior to 167.4 Ma (2σ). A second fabric formed at ~590 ̊C prior to 164.4 Ma. Na-amphibole schist associated …

Sediment Budget Of The Middle Reach Skagit River, Washington 1937-2015 Reveals Decadal Variations In Sediment Export And Storage, Amelia Deuell Rothleutner

WWU Graduate School Collection

Evaluation of historical meandering since 1937 shows that the active floodplain of the middle reach Skagit River between Rockport and Sedro-Woolley, Washington, has periodically been a significant source of sediment to the lower Skagit River and delta. In response to recent findings that the Sauk-Suiattle on average only supplies approximately 30% of the sediment load observed at Mount Vernon, I examined the geomorphic change and potential sediment production of the middle reach to test whether it is a significant source to the lower river. I tested the hypothesis that the 20-mile (32-km) middle reach has been a net source of …

A Climactic Unimak Island Caldera-Forming Eruption, Aleutian Arc, Alaska: Magma Storage And Pre-Eruption P-T-Fo2-H2o Conditions Of The Rhyodacite Magma, Olivia E. (Olivia ElišKa) Anderson

WWU Graduate School Collection

Understanding the mingling interactions between felsic and mafic end-member magmas is essential in understanding the physical processes occurring in bimodal eruptions. The Fisher caldera-forming eruption (CFE), which co-erupted rhyodacite (~69 wt.% SiO₂) and basaltic andesite (~53 wt.% SiO₂) ~9400 yBP, was studied to better understand the scenarios under which bimodal CFEs erupt. The shallow rhyodacite had a pre-eruptive temperature of 877 – 908°C and the basaltic andesite had a pre-eruptive temperature of 1065 – 1147°C. Preeruptive water contents of ~4±1.5 wt.% H2O for the rhyodacite and ~0 – 2.5 wt.% H2O for the basaltic andesite suggest …

Holocene Fault Reactivation And Landscape Evolution In The Eastern Cascades, Wa, Benjamin M. Carlson

WWU Graduate School Collection

Significant uncertainty remains in how and where modest, distributed shortening is accommodated throughout the eastern Cascade Range in Washington State. Using lidar imagery, I identified a ~5 km long lineament in Swakane Canyon near Wenatchee, roughly coincident with a strand of the Entiat fault. Topographic profiles show the lineament is formed by a southwest-side-up break in slope with between 2 and 42 m of vertical separation of the ground surface. Trenching reveals deformed saprolite and colluvium consistent with southwest-side-up folding caused by blind reverse faulting at depth. Radiocarbon and luminescence dating combined with stratigraphic constraints suggest up to three Holocene …

Testing The Time Dependence Of Slip On The Western Klamath Lake Fault Zone, Oregon, Gunnar Speth

WWU Graduate School Collection

New geomorphic mapping and cosmogenic 3He geochronology on the Western Klamath Lake fault zone in southern Oregon reveals moderate, but resolvable changes in the rate of normal-fault slip rates over the past ~170 kyr. We focus on a sequence of glacial and post-glacial surfaces that record progressive offset by the fault zone over multiple time intervals. Thirty-nine new cosmogenic ³He surface exposure dates and a cosmogenic nuclide depth profile establish the first late-Pleistocene glacial chronology in the Cascade Range of Oregon and constrains the timing of the last two major glacial advances in the region at 17.6 ± 2.1 …

Interpreting The Dynamics Of Submarine Landslides Through Hydroacoustic Modeling, West Mata Volcano, Ne Lau Basin, Jonathan G. Drobiarz

WWU Graduate School Collection

Landslides are an integral process in the development of submarine volcanoes, but these events are rarely recorded and observed. Therefore, understanding how the morphology of volcanoes evolve requires information on landslides. Hydroacoustic signals were analyzed for the purposes of characterizing frequent landslides on West Mata volcano during a 5-month eruptive period. Over 200 landslide signals have been compared in conjunction with hydroacoustic modeling to better understand the dynamics that control them. We used interference patterns produced by multipath rays to identify and model these slope failures. Landslides were most clearly captured on the north and west stations, suggesting a source …

A Pulsed-Air Model Of Blue Whale B Call Vocalizations, R. P. Dziak, J. H. Haxel, T-K. Lau, S. Heimlich, Jacqueline Caplan-Auerbach, D. K. Mellinger, H. Matsumoto, B. Mate

Geology Faculty Publications

Blue whale sound production has been thought to occur by Helmholtz resonance via air flowing from the lungs into the upper respiratory spaces. This implies that the frequency of blue whale vocalizations might be directly proportional to the size of their sound-producing organs. Here we present a sound production mechanism where the fundamental and overtone frequencies of blue whale B calls can be well modeled using a series of short-duration (<1 >s) wavelets. We propose that the likely source of these wavelets are pneumatic pulses caused by opening and closing of respiratory valves during air recirculation between the lungs and …