On 1/13/2013 6:08 AM, Bob Whitmire wrote:
> Doesn't look like, though as my geologist grandfather once told me, to
> correctly identify rock one must obtain a sample, return to the lab, and
> analyze a cross-section. I think he was being pedantic.
>
> http://en.wikipedia.org/wiki/Geological_history_of_Point_Lobos
>
> Grandolite
This must be what I recall. "During the Cretaceous period the west coast of
North America was the site of an active
chain of volcanoes. Active subduction created magma chambers that fed the
volcanoes. This magma cooled slowly at depths
of 10–20 km below the earth's surface to form a granitic intrusion known as the
Santa Lucia Granodiorite. Granodiorite
is made of quartz, orthoclase, plagioclase, amphibole, and biotite mica. "
Clicking on the 'granitic' link: "*Granite* (pron.: /ˈɡrænɨt/) is a common
widely occurring type of intrusive, felsic,
igneous rock which is granular and phaneritic in texture. This rock consists
mainly of quartz, mica, and feldspar."
It appears, based on the above, that "to form a granitic intrusion" could just
as easily have been written "to form an
intrusion of granite."
Hence, it is, to the layman not given to complex terminology and subtle
distinctions, granite.
If It Looks Like a Duck Moose
--
What if the Hokey Pokey *IS* what it's all about?
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