Vp And Vs Structure Of The Yellowstone Hot Spot From Teleseismic Tomography

[1] The movement of the lithosphere over a stationary mantle magmatic source, often thought to be a mantle plume, explains key features of the 16 Ma Yellowstone?Snake River Plain volcanic system. However, the seismic signature of a Yellowstone plume has remained elusive because of the lack of adequate data. We employ new teleseismic P and S wave traveltime data to develop tomographic images of the Yellowstone hot spot upper mantle. The teleseismic data were recorded with two temporary seismograph arrays deployed in a 500 km by 600 km area centered on Yellowstone. Additional data from nearby regional seismic networks were incorporated into the data set. The VP and VS models reveal a strong low-velocity anomaly from ~50 to 200 km directly beneath the Yellowstone caldera and eastern Snake River Plain, as has been imaged in previous studies. Peak anomalies are -2.3% for VP and -5.5% for VS. A weaker, anomaly with a velocity perturbation of up to -1.0% VP and -2.5% VS continues to at least 400 km depth. This anomaly dips 30° from vertical, west-northwest to a location beneath the northern Rocky Mountains. We interpret the low-velocity body as a plume of upwelling hot, and possibly wet rock, from the mantle transition zone that promotes small-scale convection in the upper ~200 km of the mantle and long-lived volcanism. A high-velocity anomaly, 1.2% VP and 1.9% VS, is located at ~100 to 250 km depth southeast of Yellowstone and may represent a downwelling of colder, denser mantle material.

Seismic V P , V S , and V P /V S structure is imaged across the Yellowstone hot spot swell, including the hot spot track where magmatism occurred at the eastern Snake River Plain 610 m.y. B.P. Data are teleseismic P and S travel time delays that have been corrected for the well-understood upper mantle anisotropy and crustal structure. Amplitude variations in the imaged structures are 6.2%, 11.2%, and 8% for V P , V S , and V P /V S , respectively. The dominant structure is a zone which extends beneath the Snake River Plain to a depth of 190 km that is high in V P /V S and low in V P and V S . The physical state of the upper mantle is inferred by assuming isostasy, using the volume of melt segregated from the mantle that is inferred from estimates of magma addition to the crust, and using relations that scale changes in temperature, partial melt fraction and composition to density. Specifically, we infer that the low-velocity mantle beneath the Snake River Plain is partially molten up to 1.0%, and the high-velocity Yellowstone swell mantle away from the Snake River Plain is 80 K cooler and 5% depleted in basaltic component. The imaged large seismic velocity variations occur under near isothermal conditions.

Magmas are subject to a series of processes that lead to their differentiation during transfer through and storage within the Earth's crust. The depths and mechanisms of differentiation, the crustal contribution to magma generation through wall-rock assimilation, the rates and timescales of magma generation, transfer and storage, and how these link to the thermal state of the crust are subject to vivid debate and controversy. This volume presents a collection of research articles that provide a balanced overview of the diverse approaches available to elucidate these topics, and includes both theoretical models and case studies. By integrating petrological, geochemical and geophysical approaches, it provides new insights to the subject of magmatic processes operating within the Earth's crust, and reveals important links between subsurface processes and volcanism.

Treatise on Geophysics, Second Edition, is a comprehensive and in-depth study of the physics of the Earth beyond what any geophysics text has provided previously. Thoroughly revised and updated, it provides fundamental and state-of-the-art discussion of all aspects of geophysics. A highlight of the second edition is a new volume on Near Surface Geophysics that discusses the role of geophysics in the exploitation and conservation of natural resources and the assessment of degradation of natural systems by pollution. Additional features include new material in the Planets and Moon, Mantle Dynamics, Core Dynamics, Crustal and Lithosphere Dynamics, Evolution of the Earth, and Geodesy volumes. New material is also presented on the uses of Earth gravity measurements. This title is essential for professionals, researchers, professors, and advanced undergraduate and graduate students in the fields of Geophysics and Earth system science. Comprehensive and detailed coverage of all aspects of geophysics Fundamental and state-of-the-art discussions of all research topics Integration of topics into a coherent whole

This book on multiscale seismic tomography, written by one of the leaders in the field, is suitable for undergraduate and graduate students, researchers, and professionals in Earth and planetary sciences who need to broaden their horizons about seismotectonics, volcanism, and interior structure and dynamics of the Earth and Moon. It describes the state-of-the-art in seismic tomography, with emphasis on the new findings obtained by applying tomographic methods in local, regional, and global scales for understanding the generating mechanism of large and great earthquakes such as the 2011 Tohoku-oki earthquake (Mw 9.0), crustal and upper mantle structure, origin of active arc volcanoes and intraplate volcanoes including hotspots, heterogeneous structure of subduction zones, fate of subducting slabs, origin of mantle plumes, mantle convection, and deep Earth dynamics. The first lunar tomography and its implications for the mechanism of deep moonquakes and lunar evolution are also introduced.

"The American Cordilleras form a continuous orogen that extends for 12,500 km along the eastern flank of the Pacific Ocean from Arctic to Antarctic latitudes as an integral part of the circum-Pacific orogenic belt. Following two summary chapters on the overall anatomy and evolution of North and South American segments of the orogenic system, this volume includes ten seminal chapters dealing with salient aspects of the key geodynamic processes that have accompanied Cordilleran geotectonic evolution: forearc terrane accretion, arc magmatism, shallow subduction, and backarc intracontinental deformation. The papers in this volume were selected from those presented at the 2006 Backbone of the Americas Meeting, which was sponsored jointly by multiple North and South American geological societies in Mendoza, Argentina."--pub. desc.

"This volume addresses the impact of the geological sciences, from 1963-2013, in such areas as geologic hazards, mineral resources, energy resources, water resources, soil resources, geology and health, geologic education, and the informing of general public policy. The chapters focus on how earth science informs and benefits society"--Provided by publisher.

The Yellowstone hot spot has recently been shown to be a plume that extends into the transition zone. At roughly 60?120 km depth, the plume material rising beneath Yellowstone Park is sheared SW by North America Plate motion, producing a profound low velocity layer emplaced beneath the thin lithosphere. To constrain the absolute seismic velocity of the plate-sheared plume layer, fundamental mode Rayleigh wave observations have been inverted for phase velocity using the two plane wave technique. The resulting phase velocity models are inverted with Moho-converted P to S arrival times to better constrain crustal thickness and absolute S wave velocity structure to ~120 km depth. A regionalized S wave velocity model has an extremely low velocity minimum of 3.8 ± 0.1 km/s at 80 km depth beneath the hot spot track. Nonregionalized 3-D velocity models find a velocity minimum of 3.9 km/s beneath the hot spot track. Below 120 km depth, our resolution diminishes such that the lateral spreading of the plume track is not resolved. The volume of the low velocity plume layer is small and the estimated buoyancy flux for the Yellowstone plume is

Treatise on Geophysics: Seismology and Structure of the Earth, Volume 1, provides a comprehensive review of the state of knowledge on the Earths structure and earthquakes. It addresses various aspects of structural seismology and its applications to other fields of Earth sciences. The book is organized into four parts. The first part principally covers theoretical developments and seismic data analysis techniques from the end of the nineteenth century until the present, with the main emphasis on the development of instrumentation and its deployment. The second part reviews the status of knowledge on the structure of the Earths shallow layers, starting with a global review of the Earth's crustal structure. The third part focuses on the Earth's deep structure, divided into its main units: the upper mantle, the transition zone and upper-mantle discontinuities, the D region at the base of the mantle, and the Earth's core. The fourth part comprises two chapters which discuss constraints on Earth structure from fields other than seismology: mineral physics and geodynamics. Self-contained volume starts with an overview of the subject then explores each topic with in depth detail Extensive reference lists and cross references with other volumes to facilitate further research Full-color figures and tables support the text and aid in understanding Content suited for both the expert and non-expert