Re: Iceland & the Rift Valley

[stssram@st.unocal.com (Bob Myers)]

On Apr 27, 19:16, Scott wrote:
} Subject: Re: Iceland & the Rift Valley
> >> Iceland appears to be a spreading center 'filtered'
> >> through continental crust.  
> 
> >What does this mean?  How can continental crust maintain itself at a
> >spreading center? It ought to be rafted away within a few million years. It
> >sounds like you are describing East Africa (the Rift Valley), not Iceland.
> >Would you care to elaborate?
> 
> A spreading center is by definition a place where new crust is being formed. 
> As
> it is created, it IS rafted away over millions of years. The "hole" this 
> creates
> is filled by even more upwelling crust. Therefore Iceland is growing larger 
> all
> the time, and may eventually form a new continent.

Nonsense.  This doesn't answer the question.  The crust that is formed at a
spreading center is oceanic crust, not continental crust.  The quote above
said _continental crust_.

You do know there is a difference between continental and oceanic crust, right?

> The Rift Valley is a different situation. It is a fault line where land east 
> of
> the fault is moving north relative to the mainland. Thus the continent is
> being broken apart, in the same way that California will someday join 
> Vancouver
> Island, but no more crust is formed in the process.

The African Rift Valley is a transform fault?  I thought it was an incipient
spreading center.  Hmmm, no references at hand.


-- 
Bob Myers                               Unocal Energy Resources Division
Internet: Bob.Myers@st.unocal.com       P. O. Box 68076
Phone: [714] 693-6951                   Anaheim, California  92817-8076