[meteorite-list] Eagle Butte - One more time

From: LabNEMS <staff_at_meteoritecentral.com>
Date: Thu Apr 22 10:02:31 2004
Message-ID: <5.0.0.25.2.20020321113129.0247e3e0_at_mail.attbi.com>

List:

 From a customer we received a sample of the material recently
referred to and discussed on this list as Eagle Butte.

Sample chemical analysis summary:

The received material is porous and not homogeneous. There are varying
proportions
of FeO, MgO, Ca, Al, and Dolomite within "clumps". The terms "clast" and
"breccias"
are not used to define these concentrations as the boundaries are poorly
defined.

We found no detectable Ni.

In our opinion this is ferrous slag similar to the iron slag used for
road bases. (actually Canada is an important source of ferrous slag
accounting for about 26% of USA imported needs)

Bernd Pauli wrote:

"Unfortunately there is no crater information in the 5th issue of the
Catalogue. Those among us who still have access to the BBB (the
Big Blue Book = 4th edition of the Catalogue) know that Eagle Butte
is mentioned as a doubtful feature:

A disturbed area, 10 km in diameter and 30-40 million years old, may be
meteoritic, P.B. Robertson and R.A.F. Grieve, Journ. Roy. Astron. Soc.
Canada, 1975, vol. 69, p. 1, but compare T.B. Haites and H. van Hees,
Journ. Alberta Soc. Petrol. Geologists, 1962, vol. 10, p. 511. Bore
holes and electric log data for the structure, H.B. Sawatzky in, Impact
and Explosion Cratering, eds. D.J. Roddy, R.O. Pepin and R.B. Merrill,
Pergamon Press (New York), 1977, p. 461."


To Bernd's contribution I would add the work of Hodge and Sawatzky:

"Eagle Butte, Alberta
Lat/Long: N49 deg. 42', W110 deg. 30'
Diameter: 19 km
Age <65 Ma
Condition: Eroded"

"Eagle Butte is in the Cypress Hills area of southern
Alberta (Canada). Cypress Hills Provincial Park occupies
part of the eastern portion of the structure. The structure was
recognized as a geophysical anomaly long before it was found
to be an impact feature. Both surface geology and sub-surface
information from wells support its identification as such."

"The geophysical contours show a central uplift and a surrounding
ring depression."

"Meteorite Craters and Impact Structures of the Earth", Hodge, Paul,
1994, University of Cambridge Press.

And

"Two probable Late Cretaceous astroblemes in Western Canada:
Eagle Butte, Alberta and Dumas, Saskatchewan". Geophysics, 41,
1261 - 1271"


Is there existing meteoritic material associated with the Eagle Butte
structure? I don't know. All that I can say for sure is that the material we
received is not meteoritic.

A word of caution:

Some of the longer-term members of the List may remember
our involvement with material that came to be referred to as
the "Emerald Meteorite". (summary story about the "Emerald
Meteorite", for those unfamiliar with it is at:

http://www2.suite224.net/~editorsb/updates/meteorite.htm )

Our chemical analysis showed it to be a foundry
by-product, probably from the lining of a refractory kiln and not meteoritic.
Some members may still have samples of this material in their collections.

Legal consequences resulting from this were unpleasant. Fortunately
Tim McCoy's (Smithsonian) independent analysis concurred with ours
and the finders/promoters backed off.

My point ( something I'm sure that many List members have experienced)
is that it is sometimes very, very, difficult to convince someone
untrained or unfamiliar with meteoritics that what they have is of
terrestrial occurrence. If they choose a legal path it can become
costly and uncomfortable for all. I find it far better in these
circumstances,
that when asked, to offer an "opinion" on the material rather than to
speak in "absolutes" that may be heard as a denouncement.

Everyone has an opinion but denouncements can get you sued.

Of course, this is just my "opinion".

Russ K./NEMS
Received on Thu 21 Mar 2002 06:07:45 PM PST