Tomographic imaging of multiple mantle plumes in the uppermost lower mantle

Rhodes, Mark; Davies, John H.

doi:10.1046/j.0956-540x.2001.01512.x

Cited by 23 publications

(12 citation statements)

References 31 publications

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“…Schmincke, 1982;Holik et al, 1991;Watts, 1994;Hoernle et al, 1995, Neumann et al, 1995Carracedo et al, 1998;Dañobeitia and Canales, 2000;Rhodes and Davies, 2001). However, numerous inconsistencies between the evolution of the Canary Islands and the classical hot spot scheme have been reported by Hoernle and Schmincke (1993).…”

Section: Geological Backgroundmentioning

confidence: 99%

Seismic properties of the upper mantle beneath Lanzarote (Canary Islands): Model predictions based on texture measurements by EBSD

et al. 2006

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We present a petrophysical analysis of upper mantle xenoliths, collected in the Quaternary alkali basalt fields (Series III and IV) from the island of Lanzarote. The samples consist of eight harzburgite and four dunite nodules, 5 to 15 cm in size, and exhibit a typical protogranular to porphyroclastic texture. An anomalous foliation resulting from strong recovery processes is observed in half of the specimens. The lattice preferred orientations (LPO) of olivine, orthopyroxene and clinopyroxene were measured using electron backscatter diffraction (EBSD). In most samples, olivine exhibits LPOs intermediate between the typical single crystal texture and the [100] fiber texture. Occasionally, the [010] fiber texture was also observed. Simultaneous occurrence of both types of fiber textures suggests the existence of more than one deformation regime, probably dominated by a simple shear component under low strain rate and moderate to high temperature. Orthopyroxene and clinopyroxene display a weaker but significant texture. The LPO data were used to calculate the seismic properties of the xenoliths at PT conditions obtained from geothermobarometry, and were compared to field geophysical data reported from the literature. The velocity of P-waves (7.9 km/s) obtained for a direction corresponding to the existing seismic transect is in good agreement with the most recent geophysical interpretation. Our results are consistent with a roughly W-E oriented fastest P-wave propagation direction in the uppermost mantle beneath the Canary Islands, and with the lithosphere structure proposed by previous authors involving a crust-mantle boundary at around 18 km in depth, overlaid by intermediate material between 11 and 18 km.

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Section: Geological Backgroundmentioning

confidence: 99%

Seismic properties of the upper mantle beneath Lanzarote (Canary Islands): Model predictions based on texture measurements by EBSD

et al. 2006

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“…Globally, there has been an increasing body of evidence for the existence of deep mantle plumes, particularly on the basis of the results supplied by seismic tomography (Goes et al, 1999;Lei and Zhao, 2006;Lü et al, 2013;Montelli et al, 2004Montelli et al, , 2006Rhodes and Davies, 2001;Ritsema and Allen, 2003;Romanowicz and Gung, 2002;Zhao, 2001). In this paper we assess the mantle plume model for the Emeishan LIP based on a detailed modeling of gravity data, because neither the seismic P-wave nor S-wave velocities by themselves provide sufficient information about the density structure of the lithosphere (Mooney and Kaban, 2010).…”

Section: Introductionmentioning

confidence: 99%

Mantle origin of the Emeishan large igneous province (South China) from the analysis of residual gravity anomalies

Deng

Zhang

Mooney

et al. 2014

Lithos

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“…Many studies have claimed to trace plumes through parts of the upper mantle (e.g., Ritsema and Allen, 2003;Wolfe et al, 1997), with fewer studies extending them to the lower mantle (Bijwaard and Spakman, 1999;Montelli et al, 2004;Nataf and Vandecar, 1993;Rhodes and Davies, 2001;Wolfe et al, 1997). The recent seismic tomography of Montelli et al (2004) imaged a range of plumes, a small number of which extended all the way through the mantle and others which died out at various depths through the mantle.…”

Section: Introductionmentioning

confidence: 99%

Are splash plumes the origin of minor hotspots?

Davies

Bunge

2006

Geol

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It has been claimed that focused hot cylindrical upwelling plumes cause many of the surface volcanic hotspots on Earth. It has also been argued that they must originate from thermal boundary layers. In this paper, we present spherical simulations of mantle circulation at close to Earth-like vigor with significant internal heating. These show, in addition to thermal boundary layer plumes, a new class of plumes that are not rooted in thermal boundary layers. These plumes develop as instabilities from the edge of bowls of hot mantle, which are produced by cold downwelling material deforming hot sheets of mantle. The resulting bowl and plume structure can look a bit like the ''splash'' of a water droplet. These splash plumes might provide an explanation for some hotspots that are not underlain by thermal boundary layer-sourced plumes and not initiated by large igneous provinces. We suggest that in Earth's mantle, lithospheric instabilities or small pieces of subducting slab could play the role of the model downwelling material in initiating splash plumes. Splash plumes would have implications for interpreting ocean-island basalt geochemistry, plume fixity, excess plume temperature, and estimating core heat flux. Improved seismic imaging will ultimately test this hypothesis.

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Tomographic imaging of multiple mantle plumes in the uppermost lower mantle

Cited by 23 publications

References 31 publications

Seismic properties of the upper mantle beneath Lanzarote (Canary Islands): Model predictions based on texture measurements by EBSD

Seismic properties of the upper mantle beneath Lanzarote (Canary Islands): Model predictions based on texture measurements by EBSD

Mantle origin of the Emeishan large igneous province (South China) from the analysis of residual gravity anomalies

Are splash plumes the origin of minor hotspots?

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