Download or read book P wave Tomography of the Western United States Insight Into the Yellowstone Hotspot and the Juan de Fuca Slab written by You Tian and published by . This book was released on 2012 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: We used 190,947 high-quality P-wave arrival times from 8421 local earthquakes and 1,098,022 precise travel-time residuals from 6470 teleseismic events recorded by the EarthScope/USArray transportable array to determine a detailed three-dimensional P-wave velocity model of the crust and mantle down to 1000 km depth under the western United States (US). Our tomography revealed strong heterogeneities in the crust and upper mantle under the western US. Prominent high-velocity anomalies are imaged beneath Idaho Batholith, central Colorado Plateau, Cascadian subduction zone, stable North American Craton, Transverse Ranges, and Southern Sierra Nevada. Prominent low-velocity anomalies are imaged at depths of 0?200 km beneath Snake River Plain, which may represent a small-scale convection beneath the western US. The low-velocity structure deviates variably from a narrow vertical plume conduit extending down to ?1000 km depth, suggesting that the Yellowstone hotspot may have a lower-mantle origin. The Juan de Fuca slab is imaged as a dipping high-velocity anomaly under the western US. The slab geometry and its subducted depth vary in the north-south direction. In the southern parts the slab may have subducted down to >600 km depth. A ?slab hole? is revealed beneath Oregon, which shows up as a low-velocity anomaly at depths of ?100 to 300 km. The formation of the slab hole may be related to the Newberry magmatism. The removal of flat subducted Farallon slab may have triggered the vigorous magmatism in the Basin and Range and southern part of Rocky Mountains and also resulted in the uplift of the Colorado Plateau and Rocky Mountains.
Download or read book Multiscale Seismic Tomography written by Dapeng Zhao and published by Springer. This book was released on 2015-02-20 with total page 315 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Geologic Field trip Guide to the Volcanic and Hydrothermal Landscape of the Yellowstone Plateau written by Lisa A. Morgan and published by Government Printing Office. This book was released on 2017 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Columbia River Flood Basalt Province written by Stephen P. Reidel and published by Geological Society of America. This book was released on 2013-09-13 with total page 458 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Miocene Columbia River flood basalt province covers ~210,000 km2 of the Pacific Northwest of the United States, and forms part of a larger volcanic region that also includes contemporaneous silicic centers in northern Nevada, the basaltic and time-transgressive rhyolitic volcanic fields of the Snake River Plain and Yellowstone plateau, and the High Lava Plains of central Oregon. The Columbia River flood basalt province is accessible and well exposed, making it one of the best-studied flood basalt provinces worldwide, and it serves as a model for understanding the stratigraphic development and petrogenesis of large igneous provinces through time. This volume details our current knowledge of the stratigraphy and physical volcanology; extent, volume, and age of the lava flows; the tectonic setting and history of the province; the petrogenesis of the lavas; and hydrogeology of the basalt aquifers.
Download or read book The Interdisciplinary Earth In Honor of Don L Anderson written by Gillian R. Foulger and published by Geological Society of America. This book was released on 2015-09 with total page 390 pages. Available in PDF, EPUB and Kindle. Book excerpt: Copublished with the American Geophysical Union as American Geophysical Union Special Publication 71 This volume is a memorial to Don L. Anderson, former director of the Seismological Laboratory of the Caltech Institute of Technology, recipient of the Crafoord Prize, the National Medal of Honor, and numerous other awards. A geophysicist extraordinaire, he contributed much to our understanding of the structure and dynamics of the interior of Earth. The book, comprised largely of chapters written at Anderson's invitation, reflects his interdisciplinary career. It includes papers on anisotropy, the seismic structure of the mantle, mantle convection, the statistics of melting anomalies, planetary geology, tectonics, the thermal budget of Earth, lithospheric structure, geochemistry, and flood basalts.
Download or read book Special Papers written by and published by . This book was released on 1934 with total page 578 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Backbone of the Americas written by Suzanne Mahlburg Kay and published by Geological Society of America. This book was released on 2009 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt: "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.
Download or read book Is the Track of the Yellowstone Hotspot Driven by a Deep Mantle Plume written by Kenneth Lee Pierce and published by . This book was released on 2009 with total page 25 pages. Available in PDF, EPUB and Kindle. Book excerpt: Geophysical imaging of a tilted mantle plume extending at least 500 km beneath the Yellowstone caldera provides compelling support for a plume origin of the entire Yellowstone hotspot track back to its inception at 17Mawith eruptions of flood basalts and rhyolite. The widespread volcanism, combined with a large volume of buoyant asthenosphere, supports a plume head as an initial phase. Estimates of the diameter of the plume head suggest it completely spanned the upper mantle and was fed from sources beneath the transition zone, We consider a mantle?plume depth to at least 1,000 km to best explain the large scale of features associated with the hotspot track. The Columbia River?Steens flood basalts form a northward-migrating succession consistent with the outward spreading of a plume head beneath the lithosphere. The northern part of the inferred plume head spread (pancaked) upward beneath Mesozoic oceanic crust to produce flood basalts, whereas basalt melt from the southern part intercepted and melted Paleozoic and older crust to produce rhyolite from 17 to 14 Ma. The plume head overlapped the craton margin as defined by strontium isotopes; westward motion of the North American plate has likely ?scraped off? the head from the plume tail. Flood basalt chemistries are explained by delamination of the lithosphere where the plume head intersected this cratonic margin. Before reaching the lithosphere, the rising plume head apparently intercepted the east-dipping Juan de Fuca slab and was deflected ~250 km to the west; the plume head eventually broke through the slab, leaving an abruptly truncated slab. Westward deflection of the plume head can explain the anomalously rapid hotspot movement of 62 km/m.y. from 17 to 10 Ma, compared to the rate of ~25 km/m.y. from 10 to 2 Ma. A plume head-to-tail transition occurred in the 14-to-10-Ma interval in the central Snake River Plain and was characterized by frequent (every 200?300 ka for about 2 m.y. from 12.7 to 10.5 Ma) ?large volume (N7000 km3)?, and high temperature rhyolitic eruptions (N1000 °C) along a ~200?km-wide east?west band. The broad transition area required a heat source of comparable area. Differing characteristics of the volcanic fields here may in part be due to variations in crustal composition but also may reflect development in differing parts of an evolving plume where the older fields may reflect the eruption from several volcanic centers located above very large and extensive rhyolitic magma chamber(s) over the detached plume head while the younger fields may signal the arrival of the plume tail intercepting and melting the lithosphere and generating a more focused rhyolitic magma chamber. The three youngest volcanic fields of the hotspot track started with large ignimbrite eruptions at 10.21, 6.62, and 2.05 Ma. They indicate hotspot migration N55° E at ~25 km/m.y. compatible in direction and velocity with the North American Plate motion. The Yellowstone Crescent of High Terrain (YCHT) flares outward ahead of the volcanic progression in a pattern similar to a bow-wave, and thus favors a sub-lithospheric driver. Estimates of YCHT-uplift rates are between 0.1 and 0.4mm/yr.Drainage divides havemigrated northeastwardwith the hotspot. The Continental Divide and a radial drainage pattern nowcenters on the hotspot. The largest geoid anomaly in the conterminous U.S. is also centered on Yellowstone and, consistent with uplift above a mantle plume. Bands of late Cenozoic faulting extend south and west from Yellowstone. These bands are subdivided into belts based both on recency of offset and range-front height. Fault history within these belts suggests the following pattern: Belt I ? starting activity but little accumulated offset; Belt II ? peak activity with high total offset and activity younger than 14 ka; Belt III?waning activitywith large offset and activity younger than 140 ka; and Belt IV ? apparently dead on substantial range fronts (south side of the eastern Snake River Plain only). These belts of fault activity have migrated northeast in tandem with the adjacent hotspot volcanism. On the southern arm of the YCHT, fault activity occurs on the inner, western slope consistent with driving by gravitational potential energy, whereas faulting has not started on the eastern, outer, more compressional slope. Range fronts increase in height and steepness northeastward along the southern-fault band. Both the belts of faulting and the YCHT are asymmetrical across the volcanic hotspot track, flaring out 1.6 times more on the south than the north side. This and the southeast tilt of the Yellowstone plumemay reflect southeast flow of the upper mantle.
Download or read book Slab Fragmentation Edge Flow and the Origin of the Yellowstone Hotspot Track written by David E. James and published by . This book was released on 2011 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Snake River Plain/Yellowstone (SRP/Y) volcanic province is widely considered a classic example of a plume generated continental hotspot. Here we present new S-wave and P-wave tomographic images that suggest an alternative subduction-related process by which volcanism along the SRP/Y hotspot track results from slab fragmentation, trench retreat, and mantle upwelling at the tip and around the truncated edges of the descending plate. Our seismic images of the upper mantle in the depth range 300?600 km show that the subducted oceanic plate extends locally eastward well into the mantle beneath stable North America. The break-up and along-strike fragmentation of the descending plate is related in both time and space to the onset of flood volcanism and the formation of the SRP/Y hotspot. A sub-horizontal branch of the subducting oceanic plate, orphaned from the descending plate by the northward migration of the Mendocino triple junction, resides in the mantle transition zone (400?600 km) directly beneath the SRP/Y track. Its truncated northern edge is parallel to the northwestern margin of the hotspot track and marks the southern edge of a slab gap. A number of recent numerical and physical tank model studies suggest that a rapidly retreating and severely fragmented downgoing plate drives mantle flow around both the tip and the edges of the descending slab. Our seismic results show that the morphology of the subducting slab is appropriate for generating large-scale poloidal flow (producing flood volcanism) in the upper mantle during the re-initiation phase of slab descent ca 20 Ma and for generating smaller-scale toroidal and poloidal upwellings (producing hotspot volcanism) around both the leading tip and northern edge of the slab as it descends into the deeper upper mantle. Plate reconstructions are consistent with the timing and position of both flood and hotspot volcanism.
Download or read book Mantle Convection and Surface Expressions written by Hauke Marquardt and published by John Wiley & Sons. This book was released on 2021-07-07 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: A multidisciplinary perspective on the dynamic processes occurring in Earth's mantle The convective motion of material in Earth's mantle, powered by heat from the deep interior of our planet, drives plate tectonics at the surface, generating earthquakes and volcanic activity. It shapes our familiar surface landscapes, and also stabilizes the oceans and atmosphere on geologic timescales. Mantle Convection and Surface Expressions brings together perspectives from observational geophysics, numerical modelling, geochemistry, and mineral physics to build a holistic picture of the deep Earth. It explores the dynamic processes occurring in the mantle as well as the associated heat and material cycles. Volume highlights include: Perspectives from different scientific disciplines with an emphasis on exploring synergies Current state of the mantle, its physical properties, compositional structure, and dynamic evolution Transport of heat and material through the mantle as constrained by geophysical observations, geochemical data and geodynamic model predictions Surface expressions of mantle dynamics and its control on planetary evolution and habitability The American Geophysical Union promotes discovery in Earth and space science for the benefit of humanity. Its publications disseminate scientific knowledge and provide resources for researchers, students, and professionals.
Download or read book VP and VS Structure of the Yellowstone Hot Spot from Teleseismic Tomography written by Gregory Phillip Waite and published by . This book was released on 2006 with total page 21 pages. Available in PDF, EPUB and Kindle. Book excerpt: [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.
Download or read book The Yellowstone Hotspot written by Robert Baer Smith and published by . This book was released on 1994* with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt: Direct evidence for a plume-plate interaction as the mechanism responsible for the Yellowstone-Snake River Plain (YSRP), 16 Ma volcanic system is observation of a linear age-progression of silicic volcanic centers along the Snake River Plain 800 km to the Yellowstone caldera-- the track of the Yellowston hotspot. Caldera-forming rhyolitic volcanism, active crustal deformation, extremely high heat flow (30 times the continental average), and intensive earthquake activity in Yellowstone National Park mark the surface manifestations of the hotspot. Anomalously low, P-wave velocities in the upper-crust of the Yellowstone caldera are interpreted as solidified but still hot granitic rocks, partial melts, hydrothermal fluids and sediments. Unprecedented deformation of the Yellowstone caldera of up to 1 m of uplift from 1923 to 1984, followed by subsidence of as much as ~12 cm from 1985 to 1991, clearly reflects a giant caldera unrest. The regional signature of the Yellowstone hotspot is highlighted by an anomalous, 600 m high, topographic bulge centered on the caldera and that extends across a ~600 km-wide region. We suggest that this feature reflecs long-wavelength tumescence of the hotspot. Yellowstone is also the center of a +20 m geoid anomaly, the largest in North America, and extends ~500 km laterally from the caldera, similar in width to the geoid anomalies of many oceanic hotspots and swells. The 16 Ma trace of the Yellowstone hotspot, the seismically quiescent Snake River Plain, is surrounded by "bow-wave" or parabolic shaped regions of earthquakes and high topography. Whereas systematic topographic decay along the Snake River Plain, totaling 1,300 m, fits a model of lithospheric cooling and subsidence which is consistent with passage of the North American plate across a mantle heat source. We note that the rate of 4.5 cm/yr silicic, volcanic age progression of the YSRP includes a component of southwest motion of the North American plate, modeled at ~2.5 cm/yr, and a component of concomitant crustal extension estimated to be 1 to 2 cm/yr. The USRP also exhibits anomalous crustal structure which we believe is inherited from magmatic and thermal processes associated which the Yellowstone hotspot. This includes a thin, 2-5 km-thick surface layer compses of basalts and rhyolites and an unusually high-velocity, 6.5 km/s, mid-crustal mafic layer that we suggest reflects extinct "Yellowstone" magma systems that have replaced much of the normal granite upper-crust. Direct evidence for a mantle connection for the YSRP system is from anomalously low, P-wave velocities which extend from the crust to depths of ~200km. These properties and the kinematics of teh YSRP are consistent with an analytic model for plume-plate interaction that produces a "bow-wave" or parabolic patter of upper-mantle flow southwesterly from the hotspot, similar to the systematic patterns of regional topography and seismicity. Our unified model for the origin of the YSRP is consistent with the geologic evidence where basaltic magmas ascend from a mantle plume to interact with a silicic-rich continental crust producing partial melts of rhyolite composition and the characteristic caldera-forming volcanism of Yellowstone. Cooling and contraction of the lithosphere follows the passage of the plate over the hotspot with continuing episodic eruptions of mantle-derived basalts along the SRP.
Download or read book P and S Wave Velocity and VP VS in the Wake of the Yellowstone Hot Spot written by Derek Leigh Schutt and published by . This book was released on 2004 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Seismic Anisotropy in the Earth written by V. Babuska and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Volcanoes written by John P. Lockwood and published by John Wiley & Sons. This book was released on 2013-04-26 with total page 677 pages. Available in PDF, EPUB and Kindle. Book excerpt: Volcanoes are essential elements in the delicate global balance of elemental forces that govern both the dynamic evolution of the Earth and the nature of Life itself. Without volcanic activity, life as we know it would not exist on our planet. Although beautiful to behold, volcanoes are also potentially destructive, and understanding their nature is critical to prevent major loss of life in the future. Richly illustrated with over 300 original color photographs and diagrams the book is written in an informal manner, with minimum use of jargon, and relies heavily on first-person, eye-witness accounts of eruptive activity at both "red" (effusive) and "grey" (explosive) volcanoes to illustrate the full spectrum of volcanic processes and their products. Decades of teaching in university classrooms and fieldwork on active volcanoes throughout the world have provided the authors with unique experiences that they have distilled into a highly readable textbook of lasting value. Questions for Thought, Study, and Discussion, Suggestions for Further Reading, and a comprehensive list of source references make this work a major resource for further study of volcanology. Volcanoes maintains three core foci: Global perspectives explain volcanoes in terms of their tectonic positions on Earth and their roles in earth history Environmental perspectives describe the essential role of volcanism in the moderation of terrestrial climate and atmosphere Humanitarian perspectives discuss the major influences of volcanoes on human societies. This latter is especially important as resource scarcities and environmental issues loom over our world, and as increasing numbers of people are threatened by volcanic hazards Readership Volcanologists, advanced undergraduate, and graduate students in earth science and related degree courses, and volcano enthusiasts worldwide. A companion website is also available for this title at www.wiley.com/go/lockwood/volcanoes
Download or read book Tectonic and Magmatic Evolution of the Snake River Plain Volcanic Province written by Bill Bonnichsen and published by Idaho Geological Survey. This book was released on 2002 with total page 508 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Teleseismic P wave Tomogram of the Yellowstone Plume written by Huaiyu Yuan and published by . This book was released on 2005 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: Inversion of a new data set of teleseismic P-wave travel-times from three PASSCAL seismic deployments around the Yellowstone hotspot reveals a 100 km diameter upper mantle plume that extends from the Yellowstone volcanic caldera to 500 km depth and dips 20° to the northwest . A monotonic decrease in the velocity perturbation of the plume from -3.2% at 100 km to -0.9% at 450 km is consistent with a uniform thermal anomaly of 180°C. Where the plume crosses the 410 km discontinuity, previous research shows a depression in the 410 km discontinuity consistent with a warm plume (Fee and Dueker, 2004). Additionally, a region of high velocities extends to 250 km beneath the Wind River basin in NW Wyoming that may represent a convective downwelling of the lithosphere.
