Open Access. Powered by Scholars. Published by Universities.®
- Discipline
- Institution
Articles 1 - 10 of 10
Full-Text Articles in Volcanology
Timescales Of Magma Storage And The Pre-Eruptive History For The Most Recent Lava Flow At Mount Baker (Koma Kulshan), Wa, Desiree Cunningham
Timescales Of Magma Storage And The Pre-Eruptive History For The Most Recent Lava Flow At Mount Baker (Koma Kulshan), Wa, Desiree Cunningham
All Master's Theses
Mount Baker, ranked as a very-high threat volcano in the United States, is in a well-populated area in northern WA, putting many at risk in the event of a future eruption. Previous work on Mount Baker focused on understanding the magmatic architecture beneath the volcano and has identified multiple magmatic components that contributed to different eruptions throughout its history. The youngest lava flow in the Mount Baker Volcanic Field is the 9.8 ka Sulphur Creek lava flow. The last study conducted on this flow by Garvey (2022) determined the most recent magma mush configuration that was tapped for this eruption. …
Dynamics And Timescales Of Magmatic Processes At Cerro Uturuncu, Bolivia, Sarah Jane Rasor
Dynamics And Timescales Of Magmatic Processes At Cerro Uturuncu, Bolivia, Sarah Jane Rasor
Graduate Theses/Dissertations
Between 12-25°S latitude there is prolific volcanism fueled by the Altiplano-Puna Magmatic Body (APMB), a mid-crustal magma body above the 30° angle subduction of the Nazca plate and within 60-70 km thick South American crust. Cerro Uturuncu, a stratovolcano constructed above the center of the APMB, can provide insight to the evolution of the APMB over time. Previous research suggests that the APMB is more homogenous near its center as opposed to its edges. However, the processes that led to greater homogenization as well as the structure of the magma body below Cerro Uturuncu remain unknown. This research contributes greater …
Magma Residence Times And Pre-Eruptive Processes As Determined By Diffusion Geospeedometry And Textural Analysis—Lascar Volcano, Chile, Bennett G. Van Horn
Magma Residence Times And Pre-Eruptive Processes As Determined By Diffusion Geospeedometry And Textural Analysis—Lascar Volcano, Chile, Bennett G. Van Horn
Graduate Theses/Dissertations
Petrographic textural analysis and geochemical microanalysis of plagioclase phenocrysts was conducted to model near-liquidus residence times and to gain further insight into processes that occurred within the magma chambers sourcing historical explosive eruptions at Láscar Volcano (NE Chile). Plagioclase crystals were analyzed from representative samples of Stages II (Soncor ignimbrite), III (Tumbres scoria deposit), and IV (Talabre lava, 1993 Plinian eruption). I used laser ablation-inductively coupled plasma mass spectrometry, which was combined with previously collected electron microprobe analyses and electron backscatter images to build a representative dataset of major- and trace element contents, as well as the zoning patterns and …
Thermomechanical Evolution Of A Magmatic System During A Caldera Cycle: Okataina Volcanic Center, New Zealand, Jacob Bonessi
Thermomechanical Evolution Of A Magmatic System During A Caldera Cycle: Okataina Volcanic Center, New Zealand, Jacob Bonessi
Dissertations, Master's Theses and Master's Reports
Caldera forming eruptions represent some of the largest simultaneous releases of mass and energy on the planet and pose a looming risk on a global scale. The study of the underlying magmatic systems is integral in understanding what leads to these large eruptions. This approach pairs a suite of major and trace element profiles from plagioclase with a grain texture classification and statistical analysis using Polytopic Vector Analysis (PVA) as proxies to explore potential changes in the thermomechanical state of the magmatic system at Okataina Volcanic Complex (OVC), New Zealand through its most recent caldera cycle. Results indicate systematic changes …
Aucanquilcha Volcanic Cluster Magma Evolution And Magma Plumbing System Architecture During The Gordo Stage (6-4 Ma), Kasey Lynn Buckley
Aucanquilcha Volcanic Cluster Magma Evolution And Magma Plumbing System Architecture During The Gordo Stage (6-4 Ma), Kasey Lynn Buckley
Graduate Theses/Dissertations
Aucanquilcha Volcanic Cluster (AVC) is an 11 m.y. volcanic system in the central Andes that is evolving over four distinct stages of activity. Stages include the Aloncha (11-8 Ma), Gordo (6-4 Ma), Polán (4-2 Ma), and Aucanquilcha (Ma) stages. The AVC evolved from a series of magmatic underpinnings during the Aloncha Stage to a larger zone of melting, assimilation, storage, and homogenization (MASH) by the Polán Stage. The transition from smaller underpinnings to MASH zones began during the Gordo Stage. At ~5-2 Ma the AVC reached thermal maturity before beginning its volcanic death during the Aucanquilcha Stage. This study focuses …
Pumice Compositions And Mineral Chemistry From Lascar Volcano, Chile, Madelaine M. Stearn
Pumice Compositions And Mineral Chemistry From Lascar Volcano, Chile, Madelaine M. Stearn
Graduate Theses/Dissertations
Lascar volcano is one the most active volcano in the Central Volcanic Zone of the Andean Cordillera, with 36 Holocene eruptions including a VEI 4 eruption in April 1993. Activity has not been consistent throughout time, and therefore, the processes behind it are poorly understood. Lascar volcano has cyclic behavior and has had four stages of activity, each of which had a unique eruptive style and product composition. Stage I (<43 >ka) had primarily mafic andesite lavas erupted effusively from a stratocone. Stage II initiated with dome building events ESE of the original vent and culminated in the 26.45 ka …
Giant Plagioclase In The Steens Basalt, Se Oregon: Cumulate Entrainment Revealed By Textural And In Situ Chemical Analysis, Conner H. Toth
Giant Plagioclase In The Steens Basalt, Se Oregon: Cumulate Entrainment Revealed By Textural And In Situ Chemical Analysis, Conner H. Toth
All Master's Theses
Many of the lava flows comprising the Steens Basalt in SE Oregon, the oldest and most mafic formation of the Columbia River Basalt Group (CRBG), contain exceptionally large (up to 5 cm) and abundant (up to 40 modal %) plagioclase crystals. This thesis presents a model for giant plagioclase formation in a complex system that integrates petrographic and in situ plagioclase compositional analyses with whole-rock data and computational modeling to explain systematic textural and chemical differences between plagioclase of the lower and upper Steens Basalt sub-sections. Lower Steens plagioclase are typically more chemically homogenous than upper Steens plagioclase and exhibit …
Documenting Magma Evolution Of The Fossa Delle Felci (Salina Island, South Tyrrhenian Sea) By Integrating In Situ Plagioclase Data With Quantitative Modeling, Aaron Mayfield
All Master's Theses
Compositional diversity occurs via processes dominated by recharge, assimilation and fractional crystallization (RAFC), quantification of which can provide insights into eruption catalysts, and therefore assist in hazard mitigation. This study evaluates the relative roles of RAFC processes in Fossa delle Felci (Salina Island, Italy) magmas, which span the basalt to dacite range (52-65 wt% SiO2). Integration of petrographic, whole rock, and in situ plagioclase data with quantitative magma chamber models suggests differentiation dominated by fractional crystallization and magma recharge/mixing in reservoirs located at different crustal levels. At ~12 km depth, magma evolved through crystallization of a pyroxene dominated assemblage; plagioclase …
Documenting The Origin Of Compositional Diversity Of Subduction Zone Magmatism, Alicudi, Aeolian Arc (Southern Tyrrhenian Sea, Italy) Using In Situ Plagioclase Data, Rachel Hunt
All Master's Theses
Processes that generate magma compositional diversity are important to document because composition affects degree of explosivity, which impacts hazard mitigation. Magnesium to silicon rich magmas are produced by processes such as magma recharge, assimilation, and fractional crystallization (RAFC) that occur in subvolcanic magma chamber(s). This study evaluates how magma chamber processes contribute to compositional diversity at Alicudi Volcano, Italy. Analytical and petrographic data from ten samples that span the subaerial history include whole rock major and trace elements and strontium/neodymium isotopes, and plagioclase textural types, major and trace elements, and strontium isotopes; numerical modeling was also conducted. Integration of these …
Crustal Assimilation And Magma Recharge In The Recent Mt. Etna Magma Plumbing System: Evidence From In Situ Plagioclase Textural And Compositional Data, Brad Pitcher
Undergraduate Honors Theses
Mt. Etna is Europe's largest and most active volcano, and as a result of its proximity to populated areas, understanding the structure of its magma plumbing system and the nature of its magmatic processes is essential for better predicting eruptive hazards. The aim of this study is to document core to rim textural, chemical, and isotopic variations in plagioclase, in order to investigate the structure of the subvolcanic magma system and the processes by which magmas change composition. Nomarski Differential Interference Contrast (NDIC) imaging was used to characterize the complex textures of plagioclase crystals in six trachybasaltic samples from eruption …