A rolling mill effect in asthenosphere beneath oceanic spreading centers
In: Earth and Planetary Science Letters. Elsevier: Amsterdam. ISSN 0012-821X; e-ISSN 1385-013X, meer
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| Trefwoorden |
Crustal structure
Earth structure > Asthenosphere
Earth structure > Earth crust > Oceanic crust
Physics > Mechanics > Kinematics
Spreading centres
Marien/Kust |
| Auteurs | | Top |
- Rabinowicz, M.
- Nicolas, A.
- Vigneresse, J.L.
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| Abstract |
From structural studies in seventeen ophiolite massifs, information has been drawn about the activity of the asthenosphere beneath oceanic spreading centers. This information, together with geophysical data pertaining to oceanic ridges, has been integrated into a numerical model. It is inferred that for a last-spreading ridge (>5 cm/yr) a local diapiric uprise of melted peridodite is superimposed to the main circulation driven by the lithosphere drifting. As a result, the upward flow splits, at a depth of 35 km, into a 10-20 km wide axial jet and a horizontal flow diverging away from the ridge. The small diapir channels upward most of the periodotites. Magmatic activity in the crust is thus constrained to an area of similar horizontal extension, in agreement with ophiolitic and oceanic data. |
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