Physical Sciences and Mathematics Commons^™

Metamorphic Evolution Of The Sierra De Maz: Implications For The Timing Of Terrane Accretion On The Western Margin Of Gondwana, Andrew Tholt

WWU Graduate School Collection

The Mesoproterozoic MARA terrane of South America has been interpreted to collide and subduct beneath the Gondwana margin of South America in the Cambrian. To test the proposed tectonic model, I combine metamorphic petrology and geochronology along with quantitative thermobarometry to constrain metamorphic events and peak conditions within the Sierra de Maz of the MARA terrane and the adjacent Sierra de Ramaditas. Foliations within the Sierra de Maz are steeply east dipping, with a major sinistral reverse shear zone separating the two major units (Zaino and Maz Complexes) of the northern range. Garnet Lu-Hf records a single metamorphic event in …

Geologic Development And Ongoing Activity Of The Van Zandt Landslide Complex, Northwest Wa, Usa, Geoffrey Malick

WWU Graduate School Collection

Geomorphic mapping based on high-resolution lidar data indicates that the Van Zandt Landslide Complex (VZLC) has multiple crosscutting debris lobes (up to 51.4 x 10⁶ m³) with long runouts (H/L= 0.14; 0.21) typical of catastrophic rock avalanches. AMS ¹⁴C dates from in situ logs and lake sediment cores yield overlapping ages for emplacement of Debris Lobe 2 (1330-1285 cal. yrs. B.P) and Debris Lobe 3 (1300-1285 cal. yrs. B.P.) Although Debris Lobe 3 overlies a portion of Debris Lobe 2, it is possible that emplacement of the two deposits was nearly synchronous or in rapid succession. …

Biomonitoring In Seattle: Spatial Variation And Source-Determining Of Airborne Pollutants In High-Traffic Areas, Saba Asefa

WWU Graduate School Collection

Although transportation is a large source of air particulate pollution in the U.S., air quality is currently not routinely monitored on the street level or using methods that could routinely determine particulate composition. In this study, we will use biomonitoring- using biological organisms (in this case tree leaves) as sample collectors- and magnetic characterization of particulate matter (PM) to provide a simple and inexpensive alternative air quality monitoring apparatus that is at the human spatial level, can collect micron-sized particles, and can be found in closely-spaced locations, so that there is a dense area collection network. Magnetic methods such as …

Testing ¹⁰Be Exposure Dating Of Holocene Cirque Moraines Using Glaciolacustrine Sediments In The Sierra Nevada, California, William Cary

WWU Graduate School Collection

An ongoing study attempting to date boulders from Neoglacial moraines across the Sierra Nevada mountain range, CA using high precision cosmogenic radionuclide (CRN) exposure dating has yielded ages that contradict historical records and prior research in the range. To test whether these CRN ages have glacial significance or are merely a function of geomorphic processes that promote inheritance, I collected glaciolacustrine sediment cores to document independent glacier chronologies for the Lyell and Maclure glaciers in Yosemite National Park and the Price glaciers in the Desolation Wilderness. The Lyell glaciolacustrine cores indicate glacial advances from ~1830-1230 cal yr BP and ~610-80 …

Visible-To-Near-Infrared Spectral Variability Of Hydrated Sulfates And Candidate Mars Landing Sites: Implications For The Mastcam-Z Investigation On Nasa’S Mars-2020 Rover Mission, Darian Dixon

WWU Graduate School Collection

The Mars-2020 rover mission will explore an astrobiologically relevant ancient environment on Mars, establish geologic context of the region, assess past habitability, and cache rocks for a future sample return. The Mastcam-Z instrument is a stereoscopic, zoom-enabled multispectral imager that will be critical to these objectives. As one of the mission’s primary reconnaissance tools, Mastcam-Z’s two cameras will acquire red-green-blue (RGB) true-color images and visible-to-near-infrared (VNIR) images with 11 narrowband filters from ~400-1100 nm. Mastcam-Z’s new ~975 nm spectral filter will help characterize the ~950-1000 nm absorption band in hydrated minerals, which has not been resolvable by previous rover multispectral …

Modeling The Effects Of Climate Change On Stream Temperature In The Nooksack River Basin, Stephanie E. Truitt

WWU Graduate School Collection

Stream temperatures in mountain streams in the western Cascade Mountains are heavily influenced by factors such as discharge, air temperature, and as in the case of the Nooksack River Basin in northwest Washington State; snow and glacial melt. The Nooksack basin is sensitive to warming climates due to the regions moderate Pacific maritime climate. Previous modeling studies in the upper Nooksack basins indicate a reduction in snowpack and spring runoff, and a recession of glaciers into the 21^st century due to global climate change. How stream temperatures will respond to these changes is unknown. We use the Distributed Hydrology …

Diversity And Petrogenesis Of Rhyolites From An Intra-Oceanic Arc: Evidence From Iodp Site U1437, Izu Bonin Rear-Arc And Surrounding Area, Luan J. (Luan Jean) Heywood

WWU Graduate School Collection

Magmas from the Izu Bonin rear-arc show a geochemical signature (medium- to high-K and light rare-earth element [LREE] enriched) that resembles the average composition of the continental crust. I investigate that continent-like signature by examining a suite of rear-arc-derived mafic to felsic tephras from International Ocean Discovery Program (IODP) Site U1437, which was drilled as part of IODP Expedition 350. Volcaniclastic glasses from Site U1437 comprise a compositional series from basalt to rhyolite, aged 1.1-4.4 Ma.

Site U1437 tephras record the timespan when the Izu-Bonin arc began rifting and provide a well-dated record of changing magmatic compositions through the transition …

The Effects Of Forecasted Climate Change On Mass Wasting Susceptibility In The Nooksack River Basin, Kevin Knapp

WWU Graduate School Collection

The Nooksack River in Whatcom County, Washington­ is an essential fresh water resource for industry, agriculture, municipalities and serves as vital fish habitat. Like many mountainous watersheds in the western Cascades, the Nooksack Basin is susceptible to shallow mass wasting and debris flows because of its steep slopes, young glaciated terrain, and storms with high intensity precipitation. Understanding how projected reductions in snowpack and increased winter rainfall will affect mass-wasting susceptibility in the Nooksack basin is important, because sediment produced mass wasting will jeopardize valuable aquatic and fish habitat, increase flooding risk in the Nooksack River, and affect estuarine and …