[meteorite-list] NEW Eucrite, absolutely the strangest ever seen!]

From: j.divelbiss_at_att.net <j.divelbiss_at_meteoritecentral.com>
Date: Thu Apr 22 10:28:32 2004
Message-ID: <101920031402.1603.7530_at_att.net>

Hello all,

This post is meant for fellow neophyte geologists like myself (ie. novice).

The term gabbroic has to do with a suite of rocks that happens to include
gabbro in its' grouping. A grouping/layering of rocks with similar minerals
that reacted out of the magam, generally in the Bowen Series pattern...with
many variations...too, too many to list. Other names come from these deeply
formed rocks including pyroxenite, peridotite(deeper) and dunite(deepest). As
others have said they are plutontic (intrusive) rock...which makes them deep
formers, and not volcanic (extrusive) which are formed on/near the surface.
The close cousins from the volcanic rocks are the different basalts.

Below is a site that generalizes the forming of different igneous rocks.

 http://www.tulane.edu/~sanelson/geol111/igneous.htm

I have an extensive collection of diorite and gabbroic rocks from PA that
have many looks to it. The olivine gabbro that some of you have from me has a
close resemblance (appearance) to some of the shergottite specimens out
there. From a rock collector's standpoint...gabbro and gabbroic rocks are
very cool (slowly for that matter).

John


>
> Yes Mark's definition more closely defines a conglomerate and, more
> distantly, a breccia.
>
> A Gabbro is a type rock, usually with large visible crystals(indicating
> a slow cooling), plutonic in origin and, contains feldspar and pyroxenes
> (--if I remember correctly. Let me find my rock-types book(vs mineral
> book)to make sure)
>
> I think to be a gabbro it must contain olivne form within the pyroxenes
> but can't say for certain.
>
> Bowen where are you?(as in Bowen's Reaction
> Series)
>
> Elton
>
> N Lehrman wrote:
>
> > Mark & others,
> >
> > This is totally absurd. Look up "gabbro" if you can spell it. Then
> > write.
> >
> > Norm (an earth geologist that doesn't make up new definitions---)
> >
> > ----- Original Message -----
> > *From:* Mark Ferguson <mailto:mafer_at_imagineopals.com>
> > *To:* tett <mailto:tett_at_rogers.com>
> > *Cc:* meteorite-list_at_meteoritecentral.com
> > <mailto:meteorite-list_at_meteoritecentral.com>
> > *Sent:* Saturday, October 18, 2003 7:49 PM
> > *Subject:* Re: [meteorite-list] NEW Eucrite, absolutely the
> > strangest ever seen!
> >
> > Hi Tett and list
> >
> > A gabro is a collection of individual rocks (they don't have to be
> > the same kind of rock either) welded or held together by some
> > cemmenting substance. Here on earth, the cemment can be
> > cristobalite, opal, limestone, stiltstone, and many other items. A
> > cemment with rock in it is a manmade gabro. So, gabroic infers
> > that it is like a gabro.
> >
> > Mark
> >
>
>
>
>
> ______________________________________________
> Meteorite-list mailing list
> Meteorite-list_at_meteoritecentral.com
> http://www.pairlist.net/mailman/listinfo/meteorite-list
Received on Sun 19 Oct 2003 10:02:41 AM PDT