[meteorite-list] A question about Antarctica vs Alaska meteorite hunting.

From: Rob McCafferty <rob_mccafferty_at_meteoritecentral.com>
Date: Fri, 25 Jul 2008 15:02:01 -0700 (PDT)
Message-ID: <27339.87767.qm_at_web55202.mail.re4.yahoo.com>

I highly recommend the book "Meteorites, Ice, and Antarctica - A personal account" by William A. Cassidy.

It goes into all sorts of technical stuff and the whole history and difficulty of the operations but is also a corking good read.

My personal favourite anecdote involves 2 grad students and the punchline "Who is it?".
Anyone whom has read the book will likely already be deep belly chuckling to themselves.
Rob McC

--- On Fri, 7/25/08, Ruben Garcia <meteoritemall at yahoo.com> wrote:

> From: Ruben Garcia <meteoritemall at yahoo.com>
> Subject: Re: [meteorite-list] A question about Antarctica vs Alaska meteorite hunting.
> To: meteorite-list at meteoritecentral.com, "Mr EMan" <mstreman53 at yahoo.com>
> Date: Friday, July 25, 2008, 1:53 AM
> Great information, Thanks!
>
> Ruben Garcia
> Phoenix, Arizona
> http://www.mr-meteorite.com
> http://www.youtube.com/profile_videos?user=meteorfright&p=v
>
>
> --- On Thu, 7/24/08, Mr EMan <mstreman53 at yahoo.com>
> wrote:
>
> > From: Mr EMan <mstreman53 at yahoo.com>
> > Subject: Re: [meteorite-list] A question about
> Antarctica vs Alaska meteorite hunting.
> > To: meteorite-list at meteoritecentral.com,
> meteoritemall at yahoo.com
> > Date: Thursday, July 24, 2008, 4:24 PM
> > Hello Ruben? Good question.
> >
> > What makes the recovery in Antarctica is a combination
> of
> > rare processes and not just glaciers catching up
> > meteorites.?? It takes a rare combination of
> bedrock, ice
> > and wind to expose the meteorite fields in Antarctica.
> >
> > Meteorites falling into the main flow are likely lost
> > forever.? But if it falls along the edge of the field
> in a
> > side lobe-- not in the main glacial flow--there is a
> chance
> > it can be exposed again.? Sometimes thousands of
> years
> > later.? The ice in the top portion of the lobe
> doesn't
> > scour the bedrock and stir up rock fragments like the
> main
> > flow does and has minimal inclusions of earth rock in
> the
> > load carried by the ice. ? A lobe occurs near a
> bottleneck
> > and is like a slow motion wave getting sloshed out of
> a bath
> > tub-- being pushed out of the "tub" itself
> by the
> > main flow and rising bedrock.? When the lobe hits the
> > valley rim-- a gentle slope or buried ridge-line, the
> ice
> > is forced? up and over it, exposing the ice to very
> high
> > velocity and extremely dry winds. This action scours
> away
> > the ice matrix --perhaps even sublimates some ice
> directly
> > into water vapor.? In any event, the ice is removed
> by
> > wind action leaving the meteorites concentrated on
> > the surface.? "Concentrated" implies a
> placer
> > deposit but in fact means that in fives and tens
> meteorites
> > are exposed each season before the ice flows over the
> slope
> > and they are reburied in ice unless recovered by the
> annual
> > meteorite search teams.
> >
> > I believe that a few iron meteorites have been
> recovered in
> > glacial moraines elsewhere but that is a different
> > concentration mechanism and they certainly aren't
> > separated out from the earth rock!.? Active glaciers
> such
> > as associated with caving icebergs carry whatever load
> they
> > have inside them into the sea.
> >
> > Meteorites don't seem to survive long in moist
> frequent
> > freeze thaw environments making finding stone
> meteorites
> > remote.? I don't know the circumstances of recent
> > Canadian meteorites and couldn't say if they were
> > related to glaciers.? The environment in glacial
> fields is
> > against stones but favors irons, IMHO, so long as the
> ice
> > doesn't make icebergs but ends in annual moraine
> > building piles of debris.
> >
> > Elton
> >
> > --- On Thu, 7/24/08, Ruben Garcia
> > <meteoritemall at yahoo.com> wrote:
> > Hi all,
> > I know that many of you follow the work done in
> Antarctica
> > a lot more closely
> > than I do. I know that meteorites have been recovered
> there
> > for over two
> > decades and more recently in eastern Manitoba, Canada.
> All
> > due to ancient
> > glaciers and their movements. My questions are as
> follows:
> >
> > 1)Has anyone really searched for meteorites in other
> > glacial areas such as
> > Alaska?
> >
> > 2)Is there any reason to believe that meteorites
> > wouldn't be found there?
> > 3)Are the Alaskan glaciers old enough to sufficiently
> > "catch"meteorites?
>
>
>
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Received on Fri 25 Jul 2008 06:02:01 PM PDT