Dear Dr. Camacho,
There is one such case which is almost what you are looking for.  In the
Almora Nappe, which is one of the largest nappes of Himalaya thrust
southwards during the Tertiary orogeny,  metapelites from chlorite to
K-feldspar sillimanite(needle) zone are exposed.  Our detailed recent
studies(unpublished) have shown that this metamorphism culminated in
anatexis resulting in the Almora gneisses(dated at ~1800my).  This sequence
has been folded and intruded by a Cambroordovician granitoid(dated ~560 my)
resulting in contact metamorphic aureole which has preserved andalusite
(Joshi et al., 1993, Curr. Science)
In case you are interested I can send other details and I am also willing to
collaborate on this very interesting aspect on which you are working.

Yours sincerely
Mallickarjun Joshi
Professor
Department of Geology
Banaras Hindu University
Varanasi 221 005
INDIA
Email: [log in to unmask]

----- Original Message -----
From: Alfredo Camacho <[log in to unmask]>
To: <[log in to unmask]>
Sent: Monday, January 22, 2001 10:19 AM
Subject: Contact aureoles


> Dear all,
>
> I am looking for a rapidly cooled metamorphic terrane, containing garnet,
> that was intruded at a much later date (in the hundreds Ma) by a granite
> (or other heat source).  It would be nice if garnet was found in most of
> the isograds associated with the granite aureole.  In addition, alteration
> associated with cooling and or hydrous fluids should be minimal.
>
> The reason for this specific setting is that I want to use the granite
> thermal overprint as a natural experiment to determine the closure
> temperature of garnet by looking at diffusion profiles in garnet.  This
has
> a much better chance of success than carrying out laboratory diffusion
> experiments because REE diffuse slowly.
>
> Cheers
>
> Alfredo
>
> Alfredo Camacho
> School of Geology,
> The University of New South Wales,
> UNSW SYDNEY, NSW 2052,
> AUSTRALIA
>
> Tel no:  (02) 9385 (6142 or 6134)
> Fax no:  (02) 9385 5935
> Email:   [log in to unmask]