Large Igneous Provinces (LIPs) represent geologically rapid emplacements of vast quantities of igneous material into/onto Earth's crust. There is a marked correlation in the known ages of LIPs and Mesozoic extinctions and other environmental perturbations, suggesting a possible causal link between these events. However, uncertainties in matching LIP basalt ages to the stratigraphic record of Mesozoic events mean that a sedimentary tracer of volcanism would better indicate a precise coincidence between the two phenomena. Mercury (Hg) has shown potential as such a proxy. Volcanism is a major source of Hg to the natural environment, and its relatively long atmospheric residence time (0.5–2 years) allows global distribution of the element before it is deposited to sediments. However, questions remain about how the manner of LIP emplacement might influence its impact on the Hg cycle, as well as how sedimentary processes may locally overprint any global signal. Here, the Hg records of three Mesozoic events are investigated: the end-Triassic extinction (TJ: ~201.5 Ma), Cretaceous Oceanic Anoxic Event 2 (OAE 2: ~94 Ma), and the latest Cretaceous (K–Pg: ~67–66 Ma). These events coincided with markedly different LIPs: OAE 2 with multiple submarine LIPs; the K–Pg and TJ with subaerial LIPs; with the TJ also featuring release of additional thermogenic volatiles from intrusion of organic-rich lithologies by LIP sills. Additionally, mercury is used with osmium and carbon isotopes to study the temporal relationships between volcanism, weathering, and the carbon cycle during the Toarcian Oceanic Anoxic Event (~183 Ma). This work highlights the links between LIP volcanism and other surface processes, and shows that subaerial LIPs featuring thermogenic emissions are most likely to perturb the global Hg cycle, with the record of such perturbations dependent on the nature of the sedimentary archive.

The world-class Buchans Mining Camp hosts a number of high-grade, low-tonnage volcanogenic massive sulfide (VMS) deposits. The Lundberg and Engine House zones form the lower-grade stockwork to the Lucky Strike deposit and have yet to be mined. A detailed study of the Lundberg and Engine House zones was conducted to establish the stratigraphic setting of the deposits, to determine the petrology of the host volcanic rocks and distribution of alteration facies, and to characterize the mineralization with the goal of improving exploration for polymetallic massive sulfide deposits in the Buchans camp.

This book is about two families in Seattle acting out their dysfunction through a virtual world created by the families’ wrongheaded patriarchs. It attempts to explore digital world-building in the 21st century as an indefatigable expression of our cultural and personal desire to possess and produce the other, or our inability to imagine anything truly new even as we are capable of creating new forms with which to imagine and manifest that which we imagine. Note: this is an early draft of the book.

Decisions to interfere with the natural path of lava are constrained by geological, engineering and logistical factors; and legal, environmental and socio-cultural considerations. Lava flows erupted from several volcanoes around the world have threatened people and their property, motivating them to take actions to prevent or slow its advance by diverting the flow direction using channels, berms and explosives or obstructing the lava by quenching with water or armoring. Property to be protected has included government, public, commercial and private property ranging from cities and harbors to personal property. The earliest known attempt to influence the path of lava occurred in 1669 on Mount Etna, Italy, but more recent experience there occurred in the 1980s-90s. Several eruptions at Kīlauea and Mauna Loa volcanoes in Hawai‘i also provided abundant experience (1881, 1935, 1942, 1955, 1960 and several times during the on-going 1983- present eruption of Kīlauea). Additional experience relates to experimental tests and an untested berm on Mauna Loa. Most recently though, local businessmen on Kīlauea constructed earthen berms to protect their property and the local utility authority constructed novel protective structures around electric utility poles. Decisions to use mitigation strategies may be based on expert scientific opinion, but public opposition has been reported to alone be able to prevent lava mitigation. In 2014, public opinions about the use of traditional mitigation strategies (diversion by berms or bombing) to protect commercial and residential areas of Puna were mixed among residents, but there appeared to be no opposition to a new mitigation strategy that protected key areas of the electrical infrastructure and supply of electricity. To help understand public opinion about this and various mitigation strategies and people’s acceptance of additional risk to personal property to help protect important elements of their community, we conductied questionnaire surveys among residents on Kīlauea and Mauna Loa as part of a multi-university NSF Hazards SEES project. We evaluated crisis experience, hazard zonation, and community bondedness, in addition to socio-demographic and cultural factors, with beliefs concerning mitigation, including effectiveness of mitigation strategies for lava flows and others hazards; financial and legal considerations; and requirements for specialized knowledge, skills and cooperation.

<p dir="ltr">Studying changes in seismic velocities beneath two separate volcanic systems in the Aleutian arc. Focusing on eruptive behavior, this research delineates subsurface changes through the lens of changes in seismic velocity.</p>

In this dissertation, we have examined mineral assemblages and geomorphologic features in the Sisyphi Planum region of Mars, as well as examined the mineral assemblage of palagonite in Iceland. Chapter 2 is focused on the mineral assemblages detected on possible glaciovolcanic edifices in the Sisyphi Planum region of Mars. Minerals were identified utilizing visible/near-infrared orbital spectra from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM). Analysis of eleven CRISM images located on the volcanic edifices revealed three distinct spectral classes in the region which are interpreted to be: gypsum-dominated, smectite-zeolite- iron oxide-dominated (possibly palagonite), and polyhydrated sulfate-dominated material. The possible palagonite detections on the volcanic edifices, the geomorphology of the region, and the analogous terrestrial mineralogy of subglacial eruptions strongly suggests the formation of these minerals during subglacial eruptions or associated hydrothermal systems. This implies that thick water ice sheets were present in this region in the late Noachian or early Hesperian, and that the subglacial hydrothermal systems could have supported habitable environments with excellent biosignature preservation potential. Chapter 3 is focused on evaluating the variability of the composition and crystallinity of palagonite on Earth in order to inform efforts to identify it on Mars. We hypothesized that variability in palagonite composition and crystallinity could occur due to differences in environmental conditions during formation. Palagonite samples were collected in Iceland at subglacial volcanic sites around Reykjavík in the Western Volcanic Zone, on the southern coast in the Eastern Volcanic Zone, and from the Herðubreið tuya and Askja volcano in the Northern Volcanic Zone. Visible/near-infrared reflectance spectroscopy, thermal-infrared emission spectroscopy, and quantitative XRD were used to assess the bulk mineralogy, crystallinity, and clay composition of all samples. Results show the sampled palagonites contain partially devitrified glass, unaltered glass, and secondary minerals including clay minerals, poorly crystalline ferric oxides, and zeolites. However, one sample (SCoast01) shows a vastly different mineral assemblage in all sample techniques, including well-crystalline Fe/Mg-clays as opposed to the poorly-crystalline Al-clays observed in our other samples. Based on previous studies of subaqueous palagonites and the location this sample was collected from, we hypothesize that the SCoast01 sample was formed in a submarine environment rather than subglacial. This suggests that it may be possible to differentiate submarine vs. subglacial palagonite on Earth based on composition and from remote sensing observations on Mars. Chapter 4 is a geomorphologic study of the Sisyphi Planum region of Mars where we identified and classified the tops of the Sisyphi Montes as well as geomorphologically mapped the Sisyphi Planum region. Here, we address an overarching question: What is the relationship between the Sisyphi Montes and the ice in this region? To do this, we identified 106 edifices in the region and classified them into five categories: 1) flat topped, 2) rounded tops, 3) sharp peaks, 4) cratered peaks, and 5) height less than 300 meters – a “catch-all” category for all features below the specified height, which exhibit less distinctive morphologies in MOLA topography. While many of the edifices could be sub-glacial in origin, we find that the only morphologic class that exhibits uniquely subglacial morphologies are the flat-topped edifices. These edifices are similar to terrestrial tuyas, which form when a subglacial volcano breaches an ice sheet and erupts a plateau of sub-aerial lavas. Based on the geomorphologic map and topographic data, we have shown that flat-topped edifices are all located outside of regions that we map as the Mantled Unit, which we infer to be related to the Dorsa Argentina Formation. The combination of the flat topped edifices and their location outside of the mapped ice-related regions strongly suggests that the ice in the region was once more extensive than what is currently observed. While this has been proposed in the past, it has not been documented how far the ice sheet could have extended. Here we show that the ice must have extended to at least as far as the flat topped edifices in the region. The combination of these chapters using both mineralogy and morphology suggest that the Sisyphi Planum region of Mars was subglacial in origin. <br><br>

Widespread, mid-Miocene rhyolite volcanism of eastern Oregon that are coeval or slightly postdate flood basalts of the Columbia River Basalt Province allows for mapping crustal domains using radiogenic and stable isotopes. Rhyolites are thought to be derived in large part by partial melting of the crust and thus yield direct information on the composition of the crust. Silicic volcanism is expressed in the form of numerous domes and tuffs exposed over a wide area (~300 km in N-S dimension and ~200 km in E-W dimension) west of the presumed craton boundary, which runs parallel but mostly east of the Oregon-Idaho state border as delineated by geophysical characteristics and isotopic transitions, including the 87Sr/86Sri = 0.7060 line (MSL) and 87Sr/86Sri = 0.7040 (CSL). 87Sr/86Sri of twenty-seven silicic units are variable and some are high. Sr isotopic ratios are inconsistent with the location of the traditional MSL and CSL boundaries. A primary control on the 87Sr/86Sri isotope variations may reflect changes in the crustal make-up of Paleozoic accreted terranes of a particular area rather than arising from a westward-dipping decollement that moved cratonic lithosphere below accreted terranes in eastern Oregon. A secondary control on observed isotopic ratios may be related to the amount and composition of basalt involved in the generation of rhyolites. This could lead to higher or lower 87Sr/86Sri relative to the surrounding crust because de facto coeval mafic magmas of the Columbia River Basalt Group have a wide range of Sr isotopic signatures. While Pb isotope data is incomplete for all samples of this study, the available data indicate a significant range in Pb isotopes. Yet, data of individual regions tend to plot close to one another relative to the entire data distribution. Comparison of samples from this study in a more regional view indicates the samples generally fall within the previously defined lead isotope boundaries of the main-phase Columbia River Basalt Group lavas. [lowercase delta]¹⁸O values range from below 2 parts per thousand to above 9 parts per thousand. In addition, there is a crude trend of rhyolites having lower [lowercase delta]¹⁸O and more radiogenic ⁸⁷Sr/⁸⁶Sr[subscript i] ratios. The lowest oxygen ratios (< 2 parts per thousand) are found in rhyolites ~80 km west of the cratonic margin, potentially reflecting remelting or assimilation of hydrothermally altered crust. Low [lowercase delta]¹⁸O of selected rhyolite flows cannot be explained by remelting of Cretaceous plutons of the Idaho Batholith and appear irreconcilable with remelting of altered silicic rocks at centers of multiple, confocal caldera cycles- both processes that have been proposed to explain low [lowercase delta]¹⁸O of rhyolites of the Snake River Plain-Yellowstone area.

Subduction zone volcanoes are a major natural hazard, frequently endangering lives and livelihoods. The eruptive history of many subduction zone volcanoes includes the extrusion of blocky, silicic lava that forms domes or flows, but we do not yet understand what determines the duration of dome-forming behaviour, what path magma may take to the surface, or how these systems may change over time. This thesis presents an investigation of the Santiaguito complex of lava domes and flows in Guatemala, which has been erupting continuously since its inception in 1922. The Santiaguito lavas are predominantly dacitic to andesitic, with a gradual reduction in SiO2 content from ~66 wt% in the 1920s, to ~62 wt% in 2002. This is consistent with a ~15% decrease in the extent of fractional crystallization over that time. The compositions of plagioclase phenocryst cores indicate a diminished role for magma mixing after the 1940s. I model the Santiaguito system as progressively extracting magma from an extensive, chemically-stratified storage zone. Petrological data are consistent with a storage zone extending from ~25 to ~12 km depth, and magma storage temperatures of ~940 to ~980°C. Phenocryst-hosted apatites suggest melt in this storage zone contained 401 to 1199 ppm S, 600 to 1300 ppm F, and 4100 to 6200 ppm Cl. Ascending magma may pass slowly through a conduit bottleneck, or plug, at shallow depths; groundmass texture suggests that melt rigidifies at or near the base this plug. Pre-eruptive melt volatile concentrations suggest time-averaged fluxes of 40 to 263 Mg d-1 SO2, 32 to 145 Mg d-1 HF, and 247 to 708 Mg d-1 HCl, giving ratios of 0.6 to 0.8 HF/SO2, and 2.7 to 6.2 HCl/SO2. These results are consistent with the few direct measurements of SO2 at Santiaguito, and with measured halogen emissions from other silicic dome-forming systems.

This study describes the tectono-stratigraphic and climatic record of the NE Arabian Sea during the Cenozoic.  Compilation of regional knowledge and subsurface observations has in this thesis provided new interpretations and insights into the records present along this passive margin.  The first is the rifting period (80-65 Ma) and the identification of a syn-rift volcanic sequence, comparable to other volcanic rifted margins.  This is followed by the record of a drift sequence (~65 Ma to present day), composed of extensive carbonate platforms and an infill sequence of siliciclastic deposits.  The analysed drift sequence (sink) is partly the result of the erosion of the hinterland (source) characterised by the India-Eurasia continent-continent collision.  Influence of regional climate and/or tectonic forces on the accumulation rate in the sink was tested, but not conclusive as the study area (Upper Indus Fan) covers only a limited part of the sedimentary record of the Indus Fan.  The thermal regime of the western margin of India is sparsely sampled, but once analysed, allows the definition of first order constraints on multiple rifting events.  The post-rift subsidence of the margin is slow and anomalous for &gt;28 m.y. after break-up, potentially in relation with vigorous asthenospheric convection and a sharp ocean-continent boundary.  Past and present fluid flow is recorded in the sedimentary sequence of the Upper Indus Fan.  The first is related to gas hydrate occurrence and is the result of the migration of fluids by a plumbing system to the shallow subsurface, expressed by bottom-simulating reflections crosscutting stratal reflections.  A longer term fluid migration is recorded in this basin by the longest lived (~22 m.y.) mud volcano field recorded to date.

The vulnerability of communities at risk from volcanic activity at Volcan Tungurahua, Ecuador and Mount Rainier in the USA provided the focus for this thesis. The research aimed to develop an integrated approach to risk assessments that combined both hazard and vulnerability analysis. In phase one, the study developed a novel methodology to assess volcanic threat that utilised previously published data. This semi-quantitative approach integrated measures of both hazard and exposure factors, allowing the relative threat to different communities to be ranked. By avoiding the complex quantitative analysis associated with traditional risk assessments of the multiple hazards associated with volcanic activity, this methodology may be applied where comprehensive historic and geological data may be lacking, as well as facilitating understanding amongst non-specialists and members of the public. The second phase of the research investigated human vulnerability, with an exploratory study carried out in Ecuador. This utilised a questionnaire survey aimed at eliciting an individual’s beliefs and attitudes towards volcanic risk, which provided the basis for a more comprehensive exploration of social vulnerability conducted in the USA. This investigated further the role of socio-economic features and psychological characteristics, such as risk perception, hazard salience and self-efficacy, in promoting self-protective behaviour, and examined the relative importance of these factors in determining vulnerability. The theoretical underpinnings of this research suggest that individuals with certain socio-economic characteristics may incur greater losses during a disaster, whilst perceptual processes may influence how an individual responds to a hazardous event. Little evidence was found to support the socio-economic model of vulnerability, which prevented the integration of the two research phases. However, perceptual factors were found to be significant predictors in the adoption of protective hazard adaption. This suggests that targeting risk mitigation and communication strategies to address these psychological constructs may be more important for reducing overall vulnerability than focusing efforts towards specific socio-economic groups.