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Environmental Fate Of Sulfur In Sulphur Creek, Valles Caldera, Nm: Implications For Metal Transport And Water Quality, Daniel Lavery
Environmental Fate Of Sulfur In Sulphur Creek, Valles Caldera, Nm: Implications For Metal Transport And Water Quality, Daniel Lavery
Earth and Planetary Sciences ETDs
The 1.2 Ma Valles Caldera in north-central New Mexico hosts a young igneous volcanic hydrothermal system after the model proposed in Goff and Janik (2000). The Sulphur Springs area within Valles Caldera is an acid-sulfate area typical of this model, discharging acidic waters (pH 1.5-3) formed by oxidation of magmatic H2S at the surface. We report on samples obtained from springs and streams collected between October 2021 and May 2023 in the Sulphur Creek and Alamo watersheds. Sulphur Creek receives input from Sulphur Springs and exhibits low pH (2-4) and high concentrations of Al (≤110 mg/L), Fe (≤60 …
Metagenomic Investigation Of Microbial Dark Carbon Fixation, Viral Interactions, And Horizonal Gene Transfer Within A Convergent Margin Subsurface Ecosystem, Timothy Joseph Rogers
Metagenomic Investigation Of Microbial Dark Carbon Fixation, Viral Interactions, And Horizonal Gene Transfer Within A Convergent Margin Subsurface Ecosystem, Timothy Joseph Rogers
Doctoral Dissertations
Convergent margins are geological regions where two or more tectonic plates collide, and the denser “subducting slab” is pushed beneath the less dense overriding plate. As the slab descends, it devolatilizes under higher temperatures and pressures, allowing dissolved inorganic carbon (DIC) and redox active volatile rich fluids to cycle between the upper crust and Earth’s mantle. These fluids migrate through cracks and fissures in the upper mantle and crust, fueling chemolithoautotrophy-based microbial ecosystems in the subsurface before they are expelled on the surface in the form of hydrothermal seeps and springs. Chemolithoautotrophic ecosystems, such as those in the Costa Rican …
Magmatic Evolution Of The Chasca Orkho Lava Series And Its Magmatic Enclaves, Volcán Ollagüe, Central Andes, Nathaniel W. Lenhard
Magmatic Evolution Of The Chasca Orkho Lava Series And Its Magmatic Enclaves, Volcán Ollagüe, Central Andes, Nathaniel W. Lenhard
MSU Graduate Theses
Magma mixing is a common factor in the creation of intermediate composition magmas and a potential instigator of a volcanic eruption. Magmatic enclaves, physical evidence of magma mixing within a volcanic system, are a phenomenon whose mechanisms remain unclear and debated. Common hypotheses explaining the occurrence of magmatic enclaves within a host lava range from the repeated injection of a new magma into a shallow reservoir to the disruption of equilibrium within a stratified magma chamber. Within the Andean Central Volcanic Zone (CVZ), the occurrence of magmatic enclaves yields similar geochemical compositions to their respective host rocks, bringing more difficulty …
Geochemical Variability & Implications For Magma Transport At 14°N On The Mid-Atlantic Ridge, Emma Elizabeth Mccully
Geochemical Variability & Implications For Magma Transport At 14°N On The Mid-Atlantic Ridge, Emma Elizabeth Mccully
Boise State University Theses and Dissertations
Observations of seafloor bathymetry and gravity surveys indicate that magma focuses in the center of slow spreading Mid-Ocean Ridge (MOR) segments, however; it is not well constrained how magma is generated, stored, and transported to the segment ends. There are two end-member models for magma transport: 1) a focused magma model wherein the magma upwells beneath the entire ridge axis, is focused and pools beneath the center of the segment, and is then transported towards the segment ends via lateral diking in the shallow crust and 2) a distributed magma model wherein magma vertically upwells and is erupted on the …
Pumice Compositions And Mineral Chemistry From Lascar Volcano, Chile, Madelaine M. Stearn
Pumice Compositions And Mineral Chemistry From Lascar Volcano, Chile, Madelaine M. Stearn
MSU Graduate Theses
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 …
Evolution Of A Flood Basalt Crustal Magmatic System: In Situ Mineral Data And Computational Modeling Of The Steens Basalt, Megan Graubard
Evolution Of A Flood Basalt Crustal Magmatic System: In Situ Mineral Data And Computational Modeling Of The Steens Basalt, Megan Graubard
All Master's Theses
Flood basalts are gigantic basaltic eruptions that modify the mass of the crust via intrusion of mantle-derived magma, and change its composition through interaction between magma and crust. The Steens Basalt, located in southeast Oregon, erupted approximately 16.8 million years ago, and is the oldest member of the Columbia River Basalt Group, the youngest and best-exposed flood basalt province on Earth. The Steens Basalt has an eruption volume of approximately 31,800 km3 and the duration of eruption is estimated to be between ~50,000 and 300,000 years. Major- and trace element whole rock data from 111 stratigraphically controlled samples from …
Insights Into The Relationship Between Mixing Duration And Volcanic Explosivity Index (Vei): Pacaya And Fuego Volcanoes, Guatemala, Nicola Mari
Dissertations, Master's Theses and Master's Reports
This study investigates whether the timing of magma mixing phenomena could be related to explosivity and style of volcanic activity. Lava flow and tephra samples, derived from observed, energetically-diverse eruptions, from Pacaya and Fuego volcanoes (Guatemala), were studied, the Volcanic Explosivity Index (VEI) was used as an indicator of eruption intensity. Polarized light microscopy and Scanning Electron Microscopy (SEM) techniques were used for textural and geochemical measurements. Results are interpreted as evolution of mixing through changes in textures of plagioclase and olivine crystals. These suggest that boxy-cellular plagioclase (high frequency in VEI 0 samples) is associated with brief mixing residence …
Volcanic Evolution Of The Southern Quinn Canyon Range: Implications For Regional Correlation Of Volcanic Units, Christina Emery
Volcanic Evolution Of The Southern Quinn Canyon Range: Implications For Regional Correlation Of Volcanic Units, Christina Emery
UNLV Theses, Dissertations, Professional Papers, and Capstones
The southern Quinn Canyon Range lies in an area of the Great Basin subjected to large-volume Oligocene-Miocene silicic volcanism and smaller volume basaltic volcanism during the Pliocene. Three major ash-flow tuff units were correlated in the southern Quinn Canyon Range (the Pahranagat Tuff, Clifford Spring Tuff, and the Cow Canyon Tuff) with regional units by utilizing U/Pb and 40 Ar/ 39Ar geochronology, geochemical correlation, and field mapping. Isotopic analysis suggests that basalt in the southern Quinn Canyon Range is part of the Death Valley-Pancake Range Basalt Zone and is similar to Reveille Range Episode 1 and 2 basalts. Further comparison …
Identification Of Endmembers For Magma Mixing In Little Sitkin Volcano, Alaska, Douglas A. Wolf
Identification Of Endmembers For Magma Mixing In Little Sitkin Volcano, Alaska, Douglas A. Wolf
Geology Theses and Dissertations
Little Sitkin island is an Aleutian calc-alkalic volcanic center that has erupted a suite of lavas ranging from andesite through rhyodacite. Whole-rock chemistry of these lavas indicates contrasting evolutionary processes; major-oxide silica variation diagrams exhibit linear trends that are suggestive of magma-mixing while trace-element trends are largely controlled by accessory-phase fractionation.
Plagioclase, the dominant phenocryst phase in all lavas, commonly occurs in two distinct populations with markedly different compositions and textures. Both normal and reverse zonation is noted in the plagioclase and clinopyroxene of several samples. In addition, clinopyroxene is found as rims on orthopyroxene grains and as cores with …
Petrology And Mineral Chemistry Of Some Jan Mayen Volcanics, Carla A. White
Petrology And Mineral Chemistry Of Some Jan Mayen Volcanics, Carla A. White
Geology Theses and Dissertations
The island of Jan Mayen is the northernmost active volcano on the Mid-Atlantic Ridge. The rocks of Jan Mayen belong to the potassic series of the alkaline rocks and appear to belong to the straddle type association. The ankaramites and alkali olivine basalts are characterized by the presence of large xenocrysts of rimmed chromium diopside, titaniferous salite, olivine (Fo83 to Fo88), magnetite and sometimes plagioclase (bytownite rimmed by labradorite). Phenocrysts of olivine (Fo74) and plagioclase (andesine) are present in several rocks. These and phenocrysts lie in a matrix composed of` titaniferous salite, olivine (Fo58), plagioclase (andesine), magnetite, biotite and sometimes …