Re: Metamorphosed welded tuffs?

From: george p (gpolkowski_at_yahoo.com)
Date: 03/16/05 

Date: 15 Mar 2005 23:06:59 -0800

Nomen Nescio wrote:
<Igneous rocks are "spewed out" by volcanoes.

Only some, and not even most. Igneous rocks solidified from molten
material, whether underground or above ground.

<Metamorphic rocks are sedimentary rocks re-heated by pressure and heat

<generated by tectonic processes.

Metamorphic rocks are any type of rock (igneous, sedimentary, or
metamorphic) that has been visibly changed by being subjected to high
pressures and/or high temperatures. ((There is also retrogressive
(retrograde or diapthoresis) metamorphism when metamorphic rocks formed
at higher temperatures are later subjected to a cooler environment and
fluids.))

<A Geologist

A better geologist

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