I beg to differ... there is legitimate scientific debate on this but a mantle plume under Iceland is very much a possibility and explains much about why Iceland is Iceland and not simply just another underwater spreading center.
Kimmer
--- In geology2@yahoogroups.com, Kim Noyes <kimnoyes@...> wrote:
>
> It's also probably/nearly certainly a Hot Spot/Mantle Plume ...
Hotspot iffy and "mantle plume" afraid not and none associated with the mid-oceanic ridge of the Atlantic ocean even though much of the magma is derived from the mantle. The last "active" mantle plume in the Atlantic basin,( and this is a debated topic amongst earth scientist if it was in fact a mantle plume), formed the island of Bermuda --as a short-lived, last sputter of a minor plume which has arose mid-North American Plate and traveled deeply under the Appalachian chain during the Cretaceous. Iceland has the happenstance and owes its existence to the mid-oceanic rift and past lower sea-levels. Iceland is one of the few spots on earth where a divergent boundary lies above sea level.
We there a "mantle plume" under Iceland there would be highly mafic( vs felsic) lava like what is found in Hawaii. Instead, the Icelandic lava has a high component of hydrated crustal rock in the melt leading to the high ash ryolitic-trending eruptions we see today.
Eman
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