[meteorite-list] Ben Guerir TKW and TAW

From: Martin H. <planetwhy_at_meteoritecentral.com>
Date: Thu Sep 8 08:55:24 2005
Message-ID: <20050908125521.42413.qmail_at_web40729.mail.yahoo.com>

Hi All,

The concept of TAW (total available weight) is the
third iteration of TKW (total known weight). The two
previous directions were made independent of each
other, but essentially came to the same conclusion. I
came up with the concept of eTKW or effective total
weight for my Accretion Desk article in June of 2004.
Here is the link:

http://www.meteoritetimes.com/Back_Links/2004/June/Accretion_Desk.htm

I based the eTKW concept on population dynamics of
animals where, say like the grizzlies in Yellowstone
National Park, there might be a known number of bears,
but situation dictates that the population in the Park
behaves as if a much lower number. So eTKW reflects
when there might be a large quantity of the material
that fell, but due to some circumstances, the actual
amount of material available in separate pieces may be
extremely low. Major examples include the Willamette
and Hoba irons.

Another take on the issue is with Kevin K.?s TRW or
total repository weight. In this method, one simply
adds up the weight of material published in collection
catalogs, or as listed in the Catalogue (British).
Kevin wrote about this in his book and in Meteorite
Magazine. This number gains great importance when much
of the original mass has been lost over time.

So the TAW is yet another attempt to quantify the
material in a way useful beyond the general statistics
of the discovery.

Anyone else want to take a stab at this issue?

Cheers,

Martin




--- Jeff Grossman <jgrossman_at_usgs.gov> wrote:

> No, I don't think so. My point is that
> "availability" depends on who
> you are. A typical scientist has neither a large
> (or any) meteorite
> collection nor a budget for purchasing specimens.
> To him or her,
> privately owned meteorites are not directly
> available. It's
> different for a researcher at a large museum, who
> has significant
> trading power and/or an acquisition budget. In the
> same way a
> collector with a small collection has little trading
> power, so many
> museum specimens seem unavailable. However,
> big-time dealers have
> the wherewithal to negotiate trades with museums for
> some very
> special meteorites not normally considered
> available. For those
> collectors or scientists with the greatest
> resources, nearly
> everything is theoretically available except for
> objects of
> extraordinary significance.
>
> So it's not a useful quantity, this "TAW." There's
> no way to define
> it unless you want to change the A to stand for
> Advertised.
>
> jeff
>
> At 08:56 PM 9/7/2005, stan . wrote:
>
> >I think you have it all backwards. institutions
> ALWAS have things
> >that the colelcting public would give their eye
> teeth to get ahold
> >of, making nearly anything in the hands of
> colelctors avalible to the
> >researchers if they want to go out and get it one
> way or the
> >other... now what lab wants to do a study on a nice
> big 100 lbs nwa
> >869 and has a 100g nakhla individual laying around
> that they dont need? :)
> >
> >
> >>Gee, I would define Total Available Weight as that
> material which
> >>is accessible and ready for use in scientific
> research. This would
> >>include the pieces in Morocco museums, but not
> pieces in the hands
> >>of collectors.
> >>
> >>Availability is a matter of perspective and
> access, which is
> >>different for different people.
> >
> >
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Received on Thu 08 Sep 2005 08:55:21 AM PDT