Capstones

Thursday, May 9th

All presentations will take place in the Rieke science Center, room 109.

3:45-4pm, “New Detrital Zircon Age Constraints for the Darrington Phyllite East of the Straight Creek-Fraser River Fault”
Iris Hernandez
The Northern Cascades Strait Creek fault system creates a divide between the Coast Plutonic Complex and western North Cascade units with a 90km offset from the west side. Small amounts of the Easton suite can also be found on the east side of the fault, with its constituent Darrington phyllite (141-155 Ma) correlated across the fault due to rock similarity. However, there are uncertainties in the age and appearance of previously dated Darrington phyllite and a phyllite found between the Kaches and Cle Elum Lakes on the east side of Strait Creek Fault. Here we present the first detrital zircon age correlation of possible Darrington phyllite across the Strait Creek Fault. We found a primary peak of 145 Ma with a notable second peak of 133 Ma. A Precambrian zircon tail was notable in Concordia plots, which aligns with detrital zircons found in units nearby not correlated to Darrington phyllite. The 133 Ma peak can mean that this unit is younger than Darrington Phyllite and could be explained by a different younger oceanic basin that accreted similarly to Darrington Phyllite but was open for longer.

4-4:15pm, “Chemical Analysis of Igneous Clasts in Metaconglomerate”
Jackson Helt
In the Tusas Mountains there are igneous units dated to two events: one at ~1.75 Ga and one ate ~1.7 Ga. A metaconglomerate rock containing igneous material was identified in the area. Geochemical data was collected from these igneous clasts using ICP-MS and compared to the geochemistry of the surrounding igneous rocks to determine if any could be the protolith of these clasts. Bulk chemical data determined that these clasts did not originate from any of the surrounding igneous material tested. Analysis of RRE abundance in the metaconglomerate suggests these clasts may be trondhjemitic.

4:15-4:30pm, “Shift in Nitrate Concentration in the Yakima River Basin”
Emma Penick
The Yakima River Basin has excessive amounts of nitrates in its groundwater. Well water tests have shown these levels to be higher than is healthy for human use and for a thriving ecosystem. Nitrates are an essential part of many ecosystems, that can enter through natural ways, but human activity can cause unnaturally high levels of this compound to enter ecosystems.  Samples have been taken from well water across the in the Satus Creek region of the Yakima River Basin going back to 1973 indicating high amounts of nitrate, but it is unclear the extent that nitrate concentrations have changed over time. Here I show data from well water samples dating from 1973 to the present comparing the different nitrate levels in the Satus Creek Region. This data suggests that humans have had a substantial impact on the nitrates present in the Yakima River Basin as there has been a notable increase over time. This project aims to broaden understanding of the human impact of agriculture on our environment and the health concerns that come with it. 

4:30-4:45pm, “Mapping the subsurface distribution of Olympia beds in the Tehaleh and Tacoma Puget Sound Lowland Region”
Sam Seabury
Glacial deposits are found throughout the Puget Sound region dating back tens of thousands of years ago (Easterbrook, 1986). Olympia beds are some of these glacial deposits described as an advanced wash that is brownish layered rock usually composed of lahars and ashes (Troost & Borden, 2001).  Olympia beds have proven to be essential for underground drainage throughout Washington due to their hydraulic conductivity. As a result, Olympia beds are significant resources for water management across the Puget Sound region. Despite their importance, the distribution of Olympia beds across the southern Puget Lowland is currently poorly constrained due to limited exposure at the surface. This project investigates unpublished drill cores from a planned city currently being built called Tehaleh. This new data will help to better define the distribution of Olympia beds in the southern Puget Lowland, which will be essential to constructing wastewater treatments to manage water and mitigate flood hazards.

4:45-5pm, “Landscape recovery after explosive volcanic eruptions: comparing 1980 Mount St Helens to 1991 Mt Pinatubo”
Elena Oliver
When stratovolcanoes erupt it causes mass panic and affects the environment. Landscape changes can be varied by the area and affect how the landscape responds. But what controls the landscape response taken after such eruptions? In my research, I have noticed that landscape response is based on the environment of the stratovolcano and how people reacted before, during, and after the eruption. The importance of this is due to volcanic eruptions being a cause for environmental changes and what we as people can do to be better prepared for them.

5-5:15pm,”North Cove, Washington Dynamic Revetment”
Billy Engelbeck
The rapid erosion at North Cove, Washington is an excellent example of the effects that erosion can have on a vulnerable coastline. Dubbed “Washaway Beach” this region has seen about 100 feet of coastline lost each year for over 100 years, making it “The fastest eroding beach in the United States” (Kaminsky, 1999). Historical erosion and accretion patterns in Pacific County have been significantly influenced by the construction of the Columbia River jetties (Kaminsky, 1999). This erosion has continued unabated throughout numerous efforts to slow the encroachment of the Pacific Ocean until the installation of dynamic revetment beginning in December of 2019. The purpose of this research is to use GIS (Global Information Systems) imagery to determine the success of the project by mapping and measuring the coastline in 15-year intervals starting in 1990. Using this data, the surf line as well as the vegetation line were documented and any structures left in between the two lines were marked as lost. This data was then compared against the data from the post revetment period (2023). The difference in the number of structures lost as well as measurements of the change in surf lines and vegetation lines should indicate that no new erosion has occurred since the installation of the revetment. Moving forward, this data will be useful in measuring the success of the project and determining if additional funding is needed to maintain the revetment into the future or another alternative should be found.