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Now at: Geodynamics Branch, Code 921, Goddard Space Flight Center, Greenbelt, MD 20771, USA.
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Geoid anomalies and dynamic topography from convection in cylindrical geometry: applications to mantle plumes on Earth and Venus
Article first published online: 2 APR 2007
DOI: 10.1111/j.1365-246X.1992.tb00850.x
Additional Information
How to Cite
Kiefer, W. S. and Hager†, B. H. (1992), Geoid anomalies and dynamic topography from convection in cylindrical geometry: applications to mantle plumes on Earth and Venus. Geophysical Journal International, 108: 198–214. doi: 10.1111/j.1365-246X.1992.tb00850.x
Publication History
- Issue published online: 2 APR 2007
- Article first published online: 2 APR 2007
- Accepted 1991 June 26. Received 1991 June 23; in original form 1990 November 28
- Abstract
- References
- Cited By
Keywords:
- convection;
- dynamic topography;
- geoid anomalies;
- hotspots;
- mantle plumes
SUMMARY
A variety of evidence suggests that at least some hotspots are formed by quasi-cylindrical mantle plumes upwelling from deep in the mantle. We model such plumes in cylindrical, axisymmetric geometry with depth-dependent, Newtonian viscosity. Cylindrical and sheet-like, Cartesian upwellings have significantly different geoid and topography signatures. However, Rayleigh number-Nusselt number systematics in the two geometries are quite similar. The geoid anomaly and topographic uplift over a plume are insensitive to the viscosity of the surface layer, provided that it is at least 1000 times the interior viscosity. Increasing the Rayleigh number or including a low-viscosity asthenosphere decreases the geoid anomaly and the topographic uplift associated with an upwelling plume. Increasing the aspect ratio increases both the geoid anomaly and the topographic uplift of a plume. The Nusselt number is a weak function of the aspect ratio, with its maximum value occurring at an aspect ratio of slightly less than 1.