Influence of a basal thermal anomaly on mantle convection

Matsumoto, Nayuta; Namiki, Atsuko; Sumita, I.

doi:10.1016/j.pepi.2006.04.005

Cited by 3 publications

(3 citation statements)

References 48 publications

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“…In order for this thermal voltage to produce a flow of current, the two metals must also be connected together at the other end so that a closed circuit is formed. Therefore, the probe must be kept several minutes at the same height in order for the system to equilibrate, and the vertical temperature profiles are determined from the time-averaged measurements at each depth (e.g., Olson, 1984;Giannandrea and Christensen, 1993;Matsumoto et al, 2006). A thermocouple can thus only measure temperature differences between the measurement junction and the reference junction.…”

Section: Temperature and Heat Flow Measurementsmentioning

confidence: 99%

“…The use of white light and a single TLC was used to determine the influence of mechanical (Namiki andKurita, 1999, 2001) and thermal boundary heterogeneities (Matsumoto et al, 2006) on thermal convection. The use of white light and a single TLC was used to determine the influence of mechanical (Namiki andKurita, 1999, 2001) and thermal boundary heterogeneities (Matsumoto et al, 2006) on thermal convection.…”

Section: Isotherms: Thermochromic Liquid Crystalsmentioning

confidence: 99%

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Laboratory Studies of Mantle Convection

Davaille

Limare

2007

Treatise on Geophysics

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Section: Temperature and Heat Flow Measurementsmentioning

confidence: 99%

Section: Isotherms: Thermochromic Liquid Crystalsmentioning

confidence: 99%

Laboratory Studies of Mantle Convection

Davaille

Limare

2007

Treatise on Geophysics

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“…Partial melting, if present, would modify the δq to δv s relation in the hottest regions: While seismic velocities will be reduced, the possibly dramatic decrease of the bulk viscosity associated with even small amounts of melt will enhance heat transfer (Matsumoto et al, 2006). As a consequence, the δq vs. δv s curve would become flat for the smallest δv s .…”

Section: Introductionmentioning

confidence: 99%

Mantle-driven geodynamo features—effects of post-Perovskite phase transition

Amit

Choblet

2009

Earth Planet Sp

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Exploring the impact of the heterogeneous lower mantle on the geodynamo requires knowledge of the heat flux anomaly across the core-mantle boundary. Most studies so far used a purely thermal interpretation of seismic shear wave anomalies to assign heterogeneous heat flux boundary conditions on numerical dynamo models, ignoring phase transition or compositional origins. A recent study of mantle convection (Nakagawa and Tackley, 2008) provides guidelines to include such non-thermal effects. Here we construct maps of heat flux across the core-mantle boundary based on a lower mantle tomography model (Masters et al., 2000) with a combined thermal and post-Perovskite phase transition interpretation. We impose these patterns as outer boundary conditions on numerical dynamo simulations and study the impact of accounting for post-Perovskite effects on the long-term time-average properties of the dynamo. We then compare our results with geophysical observations. We find in all cases that surface downwellings associated with cyclones concentrate intense non-axisymmetric magnetic flux at high-latitudes, the surface flow contains a large anticlockwise vortex at mid-latitudes of the southern hemisphere, and the inner boundary buoyancy flux is dominated by a Y 0 2 pattern. Boundary-driven time-average surface flow with some equatorial asymmetry is organized in the shell by quasi-axial convective rolls that extract more buoyancy from low-latitudes of the inner-boundary. These positive inner boundary buoyancy flux structures are found at low-latitudes of the northern hemisphere, in some places due to cyclonic flow at mid-latitudes of the southern hemisphere connecting with higher latitude cyclonic flow in the northern hemisphere. Accounting for post-Perovskite effects improves the recovery of several geodynamo observations, including the Atlantic/Pacific hemispherical dichotomy in core flow activity, the single intense paleomagnetic field structure in the southern hemisphere, and possibly the m = 1 dominant mode of inner-core seismic heterogeneity.

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Laboratory Studies of Mantle Convection

Davaille¹,

Limare²

2015

Treatise on Geophysics

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Influence of a basal thermal anomaly on mantle convection

Cited by 3 publications

References 48 publications

Laboratory Studies of Mantle Convection

Laboratory Studies of Mantle Convection

Mantle-driven geodynamo features—effects of post-Perovskite phase transition

Laboratory Studies of Mantle Convection

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