Anomalous shear wave delays and surface wave velocities at Yellowstone Caldera, Wyoming

Daniel, Robert G.

doi:10.1029/jb087ib04p02731

Cited by 32 publications

(16 citation statements)

References 29 publications

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“…The Basin and Range model of Archambeau and others (1969) is similar to the S-velocity model for rifts proposed by Knopoff (1972) in his classification of surface-wave models into five different categories, each representative of a different tectonic region (see below). It is also similar to the S-velocity model of Daniel and Boore (1982) for the Yellowstone caldera in which extremely low upper-mantle velocities are found, starting from the base of the crust and interpreted to be due to the presence of partial melt. However, other recent studies (summarized in this chapter) show that a subcrustal high-velocity lid is found above the low-velocity zone in the Basin and Range province (Priestley and Brune, 1978;Burdick and Helmberger, 1978;Priestley and others, 1980).…”

Section: Models Of the Tectonically Active Continentsupporting

confidence: 83%

“…Daniel and Boore (1982) investigated the anomalous S-velocity structure in the Yellowstone Plateau, considered to be a continental hot spot, using intermediate-period (1 to 30 sec) body and surface waves. They found extremely low Rayleigh-wave phase velocities: for example, 2.6 km/sec at 5-sec period, compared with 3.3 km/sec at the same period for the Basin and Range province (Priestley and Brune, 1978).…”

Section: Regional Modelsmentioning

confidence: 99%

“…An upper mantle lid may or may not be present in the model. Figure 11 compares the Yellowstone caldera model of Daniel and Boore (1982), the eastern Snake River Plain model of Greensfelder and Kovach (1982), and the northern Great Basin model of Priestley and Brune (1978).…”

Section: Regional Modelsmentioning

confidence: 99%

“…Daniel and Boore (1982) modeled the S-wave velocity structure beneath the Yellowstone Plateau using Rayleigh-wave phase velocities and S-wave residuals. Their final model shows S-wave velocities beneath the plateau to be lower than in the surroundings by 14 to 29 percent in the upper crust (0 to 20 km), 11 to 22 percent in the lower crust (20 to 40 km), and 12 percent in the upper mantle (Fig.…”

Section: Yellowstone Plateau and Eastern Snake River Plainmentioning

confidence: 99%

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Chapter 29: Upper-mantle velocity structure in the continental US. and Canada

Iyer¹,

Hitchcock²

1989

Geological Society of America Memoirs

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The available studies on upper-mantle structure in North America can be broadly divided into two categories: delineation of one-dimensional models, that is, the determination of P-and S-velocities as a function of depth; and computation of two-and three-dimensional models to take into account lateral heterogeneities in structure. About 50 one-dimensional models based on traveltimes, synthetic seismograms, and surfacewave velocities are currently available for continental North America. The gross features of these models are sharp velocity increases at depths near 400 and 650 km in the upper mantle beneath the whole continent and the presence of a low-velocity layer in the uppermost part of the upper mantle in the western half of the continent. A few other velocity discontinuities and velocity-gradient changes have also been documented. The most important finding from the available studies is a quantitative confirmation of what was suspected even in the early 1950s, namely, that the upper-mantle structure, particularly the structure related to the low-velocity layer, is drastically different in the tectonically active Cordillera from the stable central and eastern shield of North America. In western North America, in general, the upper-mantle velocities are low, and the lowvelocity zone is well developed and occurs at shallow depths. On the other hand, in the central and eastern parts of the continent the upper-mantle velocities are higher than in the west, and a low-velocity layer-if present at all-tends to be deep and to have a smaller velocity contrast than in the west. Available data and modeling techniques are inadequate to unambiguously resolve spatial variation in the depths to the 400-km and 650-km discontinuities and the boundaries of the low-velocity layer in North America. Apart from the broad division of the one-dimensional models into tectonically active and shield structures, any further finer scale quantitative division of the models within each tectonic unit is not warranted by the available data. Qualitatively, however, it is clear that such finer scale differences do exist, particularly in the upper 250 to 300 km of the upper mantle.The laterally heterogeneous structure of the upper mantle in North America has been studied by three-dimensional modeling using teleseismic P-and S-wave residuals. Three-dimensional inversion of P-and S-wave residual data collected over a substantial part of the North American continent show the existence of long-wavelength heterogeneous structure extending throughout the upper mantle. In addition, shortwavelength lateral heterogeneities are revealed by regional investigations. These include heterogeneous velocity structures associated with: (

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Section: Models Of the Tectonically Active Continentsupporting

confidence: 83%

Section: Regional Modelsmentioning

confidence: 99%

Section: Regional Modelsmentioning

confidence: 99%

Section: Yellowstone Plateau and Eastern Snake River Plainmentioning

confidence: 99%

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Chapter 29: Upper-mantle velocity structure in the continental US. and Canada

Iyer¹,

Hitchcock²

1989

Geological Society of America Memoirs

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show abstract

“…Teleseismic P-delays similarly characterize older parts of the Yellowstone-Snake River Plain region farther west, but the anomalies are considerably smaller being modelled as averaging about 3.5 % velocity reduction and probably represent analogous magmatic systems that have aged for several million years since the end of active rhyolitic voleanism (Evans, 1982). Daniel and Boore (1982) showed that S waves too are anomalously attenuated in the crust beneath the Yellowstone caldera and noted that a high average crustal Poisson's ratio probably indicates the presence of fluids. A large negative gravity anomaly of 60 mGal is mapped over the Yellowstone caldera and its margins (Blank and Gettings, 1974).…”

Section: Postcaldera Geochemical and Isotopic Evolutionmentioning

confidence: 99%