Fine-scale Ultra-low velocity zone layering at the core-mantle boundary and superplumes

Edward Garnero, Michael S. Thorne, Allen McNamara, Sebastian Rost

Research output: Chapter in Book/Report/Conference proceedingChapter

14 Citations (Scopus)

Abstract

Ultra-low velocity layering at the Earth's core-mantle boundary (CMB) has now been detected using a variety of seismic probes. P- and S-wave velocity reductions of up to 10's of percent have been mapped in a thin (5-50 km) layer, which commonly underlies reduced seismic shear wave speeds in the overlying few 100 km of the mantle. Ultra-low velocity zones (ULVZ) contain properties consistent with partial melt of rock at the very base of the mantle. Strong evidence now exists for a significant density increase in the layer (∼5-10% greater than reference models), which must be included in dynamical scenarios relating ULVZ partial melt to deep mantle plume genesis. 3-D geodynamical calculations involving an initially uniform dense layer in the lowermost few 100 km of the mantle result in thermo-chemical piles that are geographically well-correlated with seismic tomography low velocities, when past plate motions are imposed as a surface boundary condition. The hottest lower mantle regions underlay edges of the dense thermo-chemical piles.Ascenario is put forth where these piles geographically correlate with ultra-low velocity zones, and subsequent mantle plume genesis.

Original languageEnglish (US)
Title of host publicationSuperplumes: Beyond Plate Tectonics
PublisherSpringer Netherlands
Pages139-157
Number of pages19
ISBN (Print)9781402057496
DOIs
StatePublished - 2007

Fingerprint

low velocity zone
core-mantle boundary
pile
mantle plume
mantle
S-wave
melt
seismic tomography
plate motion
lower mantle
seismic wave
P-wave
wave velocity
boundary condition
probe
rock
chemical

ASJC Scopus subject areas

  • Environmental Science(all)
  • Earth and Planetary Sciences(all)

Cite this

Garnero, E., Thorne, M. S., McNamara, A., & Rost, S. (2007). Fine-scale Ultra-low velocity zone layering at the core-mantle boundary and superplumes. In Superplumes: Beyond Plate Tectonics (pp. 139-157). Springer Netherlands. https://doi.org/10.1007/978-1-4020-5750-2_6

Fine-scale Ultra-low velocity zone layering at the core-mantle boundary and superplumes. / Garnero, Edward; Thorne, Michael S.; McNamara, Allen; Rost, Sebastian.

Superplumes: Beyond Plate Tectonics. Springer Netherlands, 2007. p. 139-157.

Research output: Chapter in Book/Report/Conference proceedingChapter

Garnero, E, Thorne, MS, McNamara, A & Rost, S 2007, Fine-scale Ultra-low velocity zone layering at the core-mantle boundary and superplumes. in Superplumes: Beyond Plate Tectonics. Springer Netherlands, pp. 139-157. https://doi.org/10.1007/978-1-4020-5750-2_6
Garnero E, Thorne MS, McNamara A, Rost S. Fine-scale Ultra-low velocity zone layering at the core-mantle boundary and superplumes. In Superplumes: Beyond Plate Tectonics. Springer Netherlands. 2007. p. 139-157 https://doi.org/10.1007/978-1-4020-5750-2_6
Garnero, Edward ; Thorne, Michael S. ; McNamara, Allen ; Rost, Sebastian. / Fine-scale Ultra-low velocity zone layering at the core-mantle boundary and superplumes. Superplumes: Beyond Plate Tectonics. Springer Netherlands, 2007. pp. 139-157
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