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Articles 1 - 16 of 16
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Kinematic Vorticity And Porphyroclast Rotation In Mylonites Of The Norumbega Fault System: Implications For Paleoviscometry, Hendrik Lenferink
Kinematic Vorticity And Porphyroclast Rotation In Mylonites Of The Norumbega Fault System: Implications For Paleoviscometry, Hendrik Lenferink
Honors College
Crystallographic and shape preferred orientation (SPO) fabrics that develop in mylonitic shear zones can preserve the mean kinematic vorticity number (Wm) of bulk flow. Microstructural methods exploiting dynamically recrystallized quartz and porphyroclast SPO fabrics typically yield conflicting values of Wm. The Sandhill Corner Mylonite Zone of the Norumbega Fault System, Maine, USA, serves as a case study for investigating this discrepancy; Wm estimates range from 0.90 to 1.00 employing the former method (Method 1) and from 0.3 to 0.6 employing the latter method (Method 2). Using a numerical model, I show how a low-viscosity layer (LVL) surrounding clasts affects their …
Stratigraphic Architecture Of Pozuelo Mounds As Revealed By Earth Resistivity Tomography, Caeli Connolly
Stratigraphic Architecture Of Pozuelo Mounds As Revealed By Earth Resistivity Tomography, Caeli Connolly
Honors College
This study is a geoarchaeological analysis using earth resistance tomography (ERT) surveys of two of four mounds at Pozuelo (Formative Period, cal yr 3000 BP) in the Chincha Valley of coastal, southern Peru. Layers identified in the subsurface were to determine the presence or absence of regional continuity between the mounds. This effort is part of a larger investigation examining the paleoenvironmental setting of the site, and its influence on site location and use. Ten earth resistance tomography profiles were collected using an ABEM Terrameter LS2 and 81 pin array. These profiles were then topographically corrected using topographic survey data …
Lethal And Sublethal Effects Of Beauveria Bassiana On Maine Ticks Across Soil Ph, Alexander Mahar
Lethal And Sublethal Effects Of Beauveria Bassiana On Maine Ticks Across Soil Ph, Alexander Mahar
Honors College
Ticks are obligate parasite arthropods that are becoming increasingly common in northern regions of the United States. Ticks such as the black-legged tick (Ixodes scapularis) and the American dog tick (Dermacentor variabilis) are vectors for pathogens that cause a wide range of diseases, and as these ticks increase their exposure to humans, the diseases they transmit become more prevalent. This upward trend in cases of tick-borne illnesses has necessitated the pursuit of tick control methods that can be used across the diverse environments that are present in tick habitat ranges. One such control method is the fungal biological control, Beauveria …
Assessing College Students' Understanding Of Geologic Timescales, Ethan Couture
Assessing College Students' Understanding Of Geologic Timescales, Ethan Couture
Honors College
Geologic timescales are central to many concepts in the natural sciences, including evolution, climate change and plate tectonics. However, geologic time scales can be challenging to appreciate, especially for those who have not had exposure to such topics previously. During primary and secondary education (K-12) students are provided with foundational information about geology that is then further developed in specialized classes in college. Yet most students are not getting this foundation, which could arguably lead to deficits in their post-secondary education. Despite the importance of these concepts, especially for those interested in careers associated with geologic timescales, there have been …
Modeling Franconia Ridge, New Hampshire Using Structure From Motion And Developing New Techniques For Fracture Detection, Dane Johnson
Modeling Franconia Ridge, New Hampshire Using Structure From Motion And Developing New Techniques For Fracture Detection, Dane Johnson
Honors College
Bedrock fracture density is an important characteristic of bedrock that determines its structural formation, the potential for groundwater or fluid flow, and the capacity of erosion for exposed features. In the case of the Franconia Range, there are two primary bedrock lithologies that we wish to analyze. In this research, we conduct the first structural analysis and quantification of the bedrock fracture density of this region using Structure from Motion modeling and machine learning algorithms. Additionally, the algorithms were supplemented to be useful in determining fracture density in the subsurface geology of Ground-Penetrating-Radar (GPR) radargrams. The products of this work …
Riders On The Storm: Using Satellite Transmitters To Quantify American Woodcock Movement Behavior Following Extreme Weather Events, Katherine Trebilcock
Riders On The Storm: Using Satellite Transmitters To Quantify American Woodcock Movement Behavior Following Extreme Weather Events, Katherine Trebilcock
Honors College
The American Woodcock (Scolopax minor) has experienced steady declines in abundance over the past fifty years, which has raised questions as to why (Sauer et al. 1991). Migration for many birds, woodcock included, is energetically intensive, and may be the cause for greater mortality compared to other times of the year (Newton 2007). Despite this, there remains uncertainty in how conditions encountered during migration affect their movements and survival. One obstacle that birds must face is extreme weather, which has been increasing in intensity and occurrence due to climate change. How these events impact a migrating woodcock has been speculated …
Distribution Of First Row Transition Elements In Eclogites, Natalie Harmon
Distribution Of First Row Transition Elements In Eclogites, Natalie Harmon
Honors College
Surficial materials are recycled back into the deep Earth at subduction zones. The oxidation state of subducted materials affects the oxidation state of major geochemical reservoirs in the Earth, such as the mantle and the crust. First row transition elements (FRTEs), such as V and Sc, are highly redox sensitive and thus have the potential to track important redox processes in subduction zones. In this project, concentrations of FRTEs in garnet, omphacite, and rutile were determined for a global suite of oceanic eclogites, which represent exhumed subducted materials. Data were collected by LA-ICP-MS using an ESI NWR193UC laser ablation system …
Estimating Bedrock Fracture Density Of The Juneau Icefield, Ak, To Inform Glacial Erosion Models, Colby Rand
Estimating Bedrock Fracture Density Of The Juneau Icefield, Ak, To Inform Glacial Erosion Models, Colby Rand
Honors College
Understanding glacial erosion rates is important because debris eroded by a glacier can impact glacier flow speeds, protect tidewater glaciers from rapid retreat, and impact the productivity of marine ecosystems. Traditionally, glacial erosion models rely on a rock’s inherent “erodibility”, typically presented as a constant, to predict how much debris will be eroded by the glacier. However, the erodibility of bedrock varies spatially as a function of its fracture density, fracture orientation, and lithology, so the notion of applying a constant erodibility term to a whole field site does not fully capture the actual bedrock dynamics of the system. In …
The Microstructural Heterogeneity Of Ice In Jarvis Glacier, Alaska, Renée Clavette
The Microstructural Heterogeneity Of Ice In Jarvis Glacier, Alaska, Renée Clavette
Honors College
Glacier ice behaves as a viscous fluid, where flow is controlled by a number of external and internal processes. One crucial, yet sometimes overlooked, factor is ice microstructure. Studies have shown that ice crystal (grain) size, shape, and orientation influence the viscous strength of ice, and therefore its resistance to flow and deformation. Glacier flow is also impacted by friction at the bed and lateral margins. The magnitude of flow resistance due to the lateral margins is not well quantified. The goal of this overall project is to evaluate how heterogeneous optical properties of ice are that are influenced by …
Interglacial Expansion Of Alpine Glaciers In Garwood Valley, Antarctica, Laura Mattas
Interglacial Expansion Of Alpine Glaciers In Garwood Valley, Antarctica, Laura Mattas
Honors College
It is important to understand the response of the Antarctic Ice Sheet (AIS) to ongoing global atmospheric and oceanic warming to anticipate future sea-level change. There are several contrasting views in this regard. Harig and Simons (2015) concur with the IPCC (2013) conclusion that, in recent decades, outflow across the peripheral grounding lines of the ice sheet has exceeded increased accumulation on the interior surface of the ice sheet. In contrast, Zwally et al. (2015) suggest that recent surface accumulation in the interior East and West Antarctica has outpaced peripheral losses. They further suggest that this recent positive imbalance adds …
Recovering Legacy Geological Data Into A Geospatial Database Product: An Example From Baja California Norte, MéXico, Alexander C. Audet
Recovering Legacy Geological Data Into A Geospatial Database Product: An Example From Baja California Norte, MéXico, Alexander C. Audet
Honors College
This project develops a workflow for the extraction of legacy geological map data using a case study in the Baja California Norte, México by four workers over forty years. This project is unique from other digitization efforts worldwide because the data were already in an unregistered vector format, instead of a raster format. Thus, the methodology used in this project took advantage of this digital format by writing arcpy scripts for use inside of ArcMap, and using database feature manipulation software, in order to streamline the data extraction process, with the goal being to develop methods for dealing with other …
Increasing The Resolution Of The Last Glacial Maximum Record In The Tropical Andes Using 10be Cosmogenic Surface-Exposure Dating In The Cordillera Carabaya, Peru, Zachary E. Mason
Increasing The Resolution Of The Last Glacial Maximum Record In The Tropical Andes Using 10be Cosmogenic Surface-Exposure Dating In The Cordillera Carabaya, Peru, Zachary E. Mason
Honors College
Owing to the abundance of heat and moisture, the tropics is a fundamental component of the global climate system. Yet the role of the tropics in climate remains poorly understood. The Andes are home to ~95% of all tropical glaciers, making this the ideal region for studying relationships between tropical glaciers and climate. I conducted a Beryllium-10 surface exposure dating experiment using ten quartz-bearing rock samples from a series of last glacial maximum (LGM) moraines in the Minas Tira glaciofluvial valley system, Cordillera Carabaya, Peru. The AMS measured sample dates (excluding outliers) range from 24.3 ± 0.5 ka to 19.4 …
Art As A Tool To Communicate Science, Jillian Pelto
Art As A Tool To Communicate Science, Jillian Pelto
Honors College
My thesis explores effective ways to communicate science through art. My main goal is to illustrate significant environmental issues in a way that engages people emotionally, as well as intellectually. Researchers need a means of sharing fascinating things to broaden people’s horizons on science. In order to gain inspiration and ideas, I have researched and discussed a wide range of artists, past and present. This exploration has fueled the content of the body of artwork I have developed throughout this project.
Investigating The Controls On Surface Snow Δ18o Values In The Coastal Northeast Pacific: Implications For Paleoclimate Interpretations, Matthew C. Koehler
Investigating The Controls On Surface Snow Δ18o Values In The Coastal Northeast Pacific: Implications For Paleoclimate Interpretations, Matthew C. Koehler
Honors College
Stable water isotope ratios (18O and D) in snow pit (Juneau Icefield) and fresh snow (Eclipse Icefield) samples are included in a compilation of all available snow isotope data from coastal Alaska, and used to evaluate observed isotope shifts in regional paleoclimate records. I compiled existing isotope data in coastal Alaska (primarily the Saint Elias Range) in order to better understand the elevation dependence of stable atmospheric water isotope ratios in the region. The values that make up the compilation are reflective of multiple fractionation regimes associated with synoptic scale cyclonic events, described using the Cyclone-Water Isotope Model (Holdsworth and …
The Hydrological And Geochemical Role Of The C Horizon In A Glacial Till Mantled Headwater Catchment, Margaret A. Burns
The Hydrological And Geochemical Role Of The C Horizon In A Glacial Till Mantled Headwater Catchment, Margaret A. Burns
Honors College
The C horizon is the deepest soil layer that is technically unweathered, similar to the rest of the regolith beneath the bottom of the pedon. In New England, the C horizon formed from the retreat of the glaciers eroding bedrock and depositing an unsorted and unstratified glacial till on the surface. This research evaluated the hydrologic and chemical role of the C horizon, inclusive of underlying regolith, in a forested watershed at the Hubbard Brook Experimental Forest (HBEF) in New Hampshire. Results suggest that the C horizon at HBEF is extensive and heterogeneous. Traditional concepts of basal till offer a …
Heterogeneous Deformation Of Gabbroic Rocks, Calvin Mako
Heterogeneous Deformation Of Gabbroic Rocks, Calvin Mako
Honors College
The Grenville province is the exhumed remains of a more than 1 billion year old orogen. Mid to lower crustal rocks of this orogen are now exposed at the surface, affording the opportunity to examine deeper crustal processes during orogeny. I have studied an outcrop of anorthositic gabbro from the Central Metasedimentary Belt boundary thrust zone (CMBbtz) in the Grenville province of southern Ontario. The CMBbtz is a region that separates two major lithotectonic domains of this part of the Grenville province and is thought to have accommodated large scale thrusting in the mesoproterozoic era. The CMBbtz comprises large crystalline …