A post-perovskite lens and D″ heat flux beneath the central Pacific

Thorne Lay, John Hernlund, Edward Garnero, Michael S. Thorne

Research output: Contribution to journalArticle

186 Citations (Scopus)

Abstract

Temperature gradients in a low-shear-velocity province in the lowermost mantle (D″ region) beneath the central Pacific Ocean were inferred from the observation of a rapid S-wave velocity increase overlying a rapid decrease. These paired seismic discontinuities are attributed to a phase change from perovskite to post-perovskite and then back to perovskite as the temperature increases with depth. Iron enrichment could explain the occurrence of post-perovskite several hundred kilometers above the core-mantle boundary in this warm, chemically distinct province. The double phase-boundary crossing directly constrains the lowermost mantle temperature gradients. Assuming a standard but unconstrained choice of thermal conductivity, the regional core-mantle boundary heat flux (∼85 ± 25 milliwatts per square meter), comparable to the average at Earth's surface, was estimated, along with a lower bound on global core-mantle boundary heat flow in the range of 13 ± 4 terawatts. Mapped velocity-contrast variations indicate that the lens of post-perovskite minerals thins and vanishes over 1000 kilometers laterally toward the margin of the chemical distinct region as a result of a ∼500-kelvin temperature increase.

Original languageEnglish (US)
Pages (from-to)1272-1276
Number of pages5
JournalScience
Volume314
Issue number5803
DOIs
StatePublished - Nov 24 2006

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Lenses
Hot Temperature
Temperature
Pacific Ocean
Thermal Conductivity
Minerals
Iron
Observation
perovskite

ASJC Scopus subject areas

  • General

Cite this

A post-perovskite lens and D″ heat flux beneath the central Pacific. / Lay, Thorne; Hernlund, John; Garnero, Edward; Thorne, Michael S.

In: Science, Vol. 314, No. 5803, 24.11.2006, p. 1272-1276.

Research output: Contribution to journalArticle

Lay, Thorne ; Hernlund, John ; Garnero, Edward ; Thorne, Michael S. / A post-perovskite lens and D″ heat flux beneath the central Pacific. In: Science. 2006 ; Vol. 314, No. 5803. pp. 1272-1276.
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