ISSN:
1573-0581
Keywords:
diapir
;
dunite
;
Moho
;
Oman
;
ophiolite
;
wehrlite
Source:
Springer Online Journal Archives 1860-2000
Topics:
Geosciences
,
Physics
Notes:
Abstract Field data in the Oman ophiolite show that the Moho transition zone (MTZ), which is on average 300 m thick above mantle diapirs, reduces to 50 m away from diapirs, with a sharp transition at the outskirts of the diapirs. We show here that this reduction is dominantly due to compaction of a dunitic mush present above diapirs in the MTZ, with upward injection of a wehrlitic magma in the crust, and, to a lesser extent, due to tectonic stretching. In order to explain the fraction of wehrlites injected into the crust, which is in the range of 25%, it is necessary that mantle upwelling is active, with a mantle flow velocity away from diapirs several times faster than the spreading velocity. If this velocity exceeds 5 times the ridge spreading-rate, a significant part of the MTZ may be entrained down into the mantle, flowing away from the diapir as tabular dunites.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1026733019682
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