3-DIMENSIONAL SIMULATIONS OF PLUME-LITHOSPHERE INTERACTION AT THE HAWAIIAN SWELL

Citation
Wb. Moore et al., 3-DIMENSIONAL SIMULATIONS OF PLUME-LITHOSPHERE INTERACTION AT THE HAWAIIAN SWELL, Science, 279(5353), 1998, pp. 1008-1011
Citations number
41
Categorie Soggetti
Multidisciplinary Sciences
Journal title
ISSN journal
00368075
Volume
279
Issue
5353
Year of publication
1998
Pages
1008 - 1011
Database
ISI
SICI code
0036-8075(1998)279:5353<1008:3SOPIA>2.0.ZU;2-1
Abstract
Rapid lithospheric thinning by mantle plumes has not been achieved in numerical experiments performed to date. Efficient thinning depends on small-scale instabilities that convectively remove lithospheric mater ial. These instabilities are favored by hotter plumes or stronger temp erature dependence of viscosity, and a simple scaling independent of r heology controls their onset. This scaling allows extrapolation of the results of numerical experiments to the Earth's mantle. Mantle plumes between 100 and 150 kelvins hotter than the background mantle should exhibit small-scale convective rolls aligned with the plate motion. Th e unusual variation in heat flow across the Hawaiian swell may be due to such instabilities. It was found that the spreading of the plume cr eates a downwelling curtain of material that isolates it from the rest of the mantle for distances of at least 1000 kilometers from the plum e origin. This isolation has important consequences for the geochemica l heterogeneity of the lithosphere and upper mantle.