Mantle discontinuity structure beneath the Colorado Rocky Mountains and High Plains

Dueker, K. G.; Sheehan, A. F.

doi:10.1029/97jb03509

Cited by 152 publications

(128 citation statements)

References 32 publications

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“…For the same technique, measurements can differ for a single seismic station depending on back-azimuth (the direction to the earthquake from the receiver), because the structure may be different on one side of the station relative to the other (Dueker and Sheehan, 1998). Some studies stack receiver functions from all available back azimuths, a practice that tends to damp short-wavelength variations and likely underestimates the topographic variation (Lawrence and Shearer, 2006).…”

Section: Methodology For Seismic Measurementsmentioning

confidence: 99%

Correlation of seismic and petrologic thermometers suggests deep thermal anomalies beneath hotspots

Courtier

Jackson

Lawrence

et al. 2007

Earth and Planetary Science Letters

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A fundamental question regarding the dynamics of mantle convection is whether some intraplate volcanic centers, known as "hotspots," are the surface manifestations of hot, narrow, thermally driven upwellings, or plumes, rising from the lower mantle. Shown here is a global negative correlation between the thickness of the mantle transition zone (near 410-660 km depth) and petrologically determined potential temperatures of mid-ocean ridge and hotspot magmas. Hotspot potential temperatures are systematically higher than those for mid-ocean ridges, and the transition zone thicknesses beneath these hotspots are thinner. Thus, the majority of oceanic intraplate magmatic centers are associated with deep-seated thermal anomalies, suggesting that such magmatism is probably associated with thermal plumes.

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Section: Methodology For Seismic Measurementsmentioning

confidence: 99%

Correlation of seismic and petrologic thermometers suggests deep thermal anomalies beneath hotspots

Courtier

Jackson

Lawrence

et al. 2007

Earth and Planetary Science Letters

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“…Revenaugh and Jordan, 1991;Dueker and Sheehan, 1998;Deuss and Woodhouse, 2001), and no definitive physical or chemical explanation for its existence has been suggested. In the depth stacks determined here a small peak appears fairly consistently near 53.3 s, which corresponds to a depth of about 530 km.…”

Section: The 410 520 and 660 Km Discontinuitiesmentioning

confidence: 99%

Crustal thickness, discontinuity depth, and upper mantle structure beneath southern Africa: constraints from body wave conversions

Stankiewicz

Chevrot

Hilst

et al. 2002

Physics of the Earth and Planetary Interiors

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The technique of receiver function analysis is applied to the study of crustal and upper mantle structures beneath the Kaapvaal craton in southern Africa and its surroundings. Seismic data were recorded by the seismic array of 82 sites deployed from April 1997 to April 1999 across southern Africa, as well as a dense array of 32 sites near Kimberley, in operation from December 1998 to June 1999. Arrival times for phases converted at the Moho are used to determine crustal thickness. The Moho depth in the south-western section of the craton was found to vary between 37 and 40 km, except for one station that recorded a depth of 43 km (SA23). Farther north along the western block of the craton (into Botswana) the depth increases up to 43 km. The depth increases even further in the north-eastern section of the craton, where results vary from 40 to 52 km. Just north of the Kaapvaal craton, in the neighbouring Zimbabwe craton, the crustal thickness drops significantly. The results obtained there varied from 36 to 40 km. For the Kimberley area, using the dense array, the Moho depth was found to be 37.3 km. Arrivals of the Ps and Ppps phases were used to determine the Poisson's ratio in the region. This was found to be 0.26 ± 0.01. Arrivals of phases from the 410 and 660 km mantle discontinuities are used to interpret the relative positions of these discontinuities, as well as for comparison of mantle temperatures and seismic velocities in the region with global averages. In the Kimberley area the 410 and 660 km discontinuities were found at their expected depth, implying that mantle temperatures in the region are close to the global average. The seismic velocities above the '410' were found up to 5% faster than the averages from the global iasp91 model, which is fast even by Precambrian standards. In other sections of the Kaapvaal craton, the velocities are also faster than global averages, but not as fast as beneath Kimberley. In these sections, the '410' is also slightly elevated, while the '660' is depressed, which implies a slightly lower mantle temperature relative to the global average. Beneath the Kaapvaal craton we find evidence suggesting the presence of a zone with a reduced wavespeed gradient at an upper bound of approximately 300 km, which may mark the lower chemical boundary of the craton.

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“…We compared the results from 2 ‡-and 1 ‡-radius bins and we chose 2 ‡ bins in order to maximize spatial coverage while maintaining signal quality. Receiver functions of P d s paths piercing the same bin at a given depth in the mantle were gathered and stacked [26,27] using an nth root (n = 2) stacking process [28]. The non-linear stacking process enhanced coherent signals and suppressed random noise.…”

Section: Data Processing and Signal Analysismentioning

confidence: 99%

Thermal, hydrous, and mechanical states of the mantle transition zone beneath southern Africa

Blum

Shen

2004

Earth and Planetary Science Letters

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Mantle discontinuity structure beneath the Colorado Rocky Mountains and High Plains

Cited by 152 publications

References 32 publications

Correlation of seismic and petrologic thermometers suggests deep thermal anomalies beneath hotspots

Correlation of seismic and petrologic thermometers suggests deep thermal anomalies beneath hotspots

Crustal thickness, discontinuity depth, and upper mantle structure beneath southern Africa: constraints from body wave conversions

Thermal, hydrous, and mechanical states of the mantle transition zone beneath southern Africa

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