Dashtgard, Shahin

Chapter: The natural landscape of the North Shore of Vancouver is a mountainous one extending from sea level to ~1400 m. Land below ~400 m has been undergoing increasing urbanization since the 1950s. Development has encroached on areas subject to natural hazards such as floods, debris flows, slope failures, and coastal inundation. We will visit examples of these urban hazards, discuss problems of hazard identification in a forested landscape, and review urban planning and engineering responses to hazard management. Book: This volume, prepared for the 126th GSA Annual Meeting in Vancouver, Canada, offers guides to trips in the Cascadia subduction zone. The active tectonism of the region has had a profound effect on the bedrock and surficial geology of the area, and on human interactions with the geologic environment. These themes are reflected in the trips associated with the meeting. Trip topics relate to bedrock geology, volcanism and Cordilleran glaciation and deglaciation, as well as human interaction with the natural environment. The trips that discuss human interaction cover archaeology, natural hazards and the urban environment, as well as the role that local geology and tectonism have played in shaping colonization of the region since the last glaciation. The field guide volume has something for everyone!

Chapter: This field guide describes a three-day trip from Vancouver, British Columbia, to the Wells Gray–Clearwater volcanic field (WGCVF) in east-central British Columbia. The WGCVF is the site of transitional to alkali olivine basaltic volcanism erupted over the last three million years. The small volume magmas (<1 km3) erupted along preexisting normal faults related to the late stages of Cordilleran terrane amalgamation, along the boundary between the miogeoclinal and pericratonic rocks of the Kootenay terrane and the allochthonous Slide Mountain and Quesnellia terranes west of ancestral North America. The magmas are highly enriched in incompatible elements, especially large-ion lithophile elements, and are interpreted as the result of low degrees of partial melting of a heterogeneous, metasomatized mantle. Upon ascent through the crust, they carried up both crustal and mantle xenoliths. During the eruptive period of the WGCVF, at least four glacial periods have occurred. The interplay between volcanism and glaciation is captured in the wide range of volcanic features found in the region. Field trip participants will view numerous diverse volcanic landforms and deposits: from tuyas to ice-marginal valley-edge deposits, volcanoclastic-lacustrine deposits, and associated pillow lavas and hyaloclastites. <p>Book: This volume, prepared for the 126th GSA Annual Meeting in Vancouver, Canada, offers guides to trips in the Cascadia subduction zone. The active tectonism of the region has had a profound effect on the bedrock and surficial geology of the area, and on human interactions with the geologic environment. These themes are reflected in the trips associated with the meeting. Trip topics relate to bedrock geology, volcanism and Cordilleran glaciation and deglaciation, as well as human interaction with the natural environment. The trips that discuss human interaction cover archaeology, natural hazards and the urban environment, as well as the role that local geology and tectonism have played in shaping colonization of the region since the last glaciation. The field guide volume has something for everyone! --From publisher description.

This thesis characterizes the transfer of magmatic volatiles through the mantle and the crust to the atmosphere through the integration of melt inclusion data for pre-eruptive volatile contents with surface measurements of volcanic degassing (recorded in micro-gravity changes and volcanic fumarole and plume gas compositions) at two contrasting volcanoes: Sierra Negra, Galápagos Islands and Kawah Ijen, Indonesia. In particular, it explores the process of fluid transfer in the mantle, the partitioning of volatile elements during mantle melting and degassing of the magma through the crust, and the effect of near-surface (e.g., interactions with groundwater and hydrothermal fluids), and surface processes (e.g., cooling and mixing with air) on the gas species. The effects of differences in initial volatile content and internal volcano structure on the types of eruptions and emissions recorded at each volcano are also discussed. The comparison of Sierra Negra and Kawah Ijen volcanoes reveals that differences in style of volcanic activity are primarily a function of magmatic plumbing system as opposed to differences in initial volatile content. In both cases, permeability of the crust and degassing style have exerted a dominant control over the recent style of activity (last century). Recent eruptions at Sierra Negra are not necessarily associated with magma recharge into shallow reservoirs but can be caused by subtle changes in the pressure regime of a magma chamber, a process which is closely associated with degassing and system permeability. Large explosive eruptions at Kawah Ijen are currently impeded by the open system (permeable) flow of magma and gas through the plumbing system. Hydrothermal systems play an important role in controlling the permeability of a system and the composition of the gases measured at the surface. The comparison of theoretically modeled gas compositions with actual measured compositions is an effective approach to studying the influence of hydrothermal systems at open vent volcanoes.