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Port Orford Meteorite Hoax - Part 6 of 6

PLOTKIN H. (1993) The Port Orford Meteorite Hoax
(Sky & Tel., September 1993, pp. 35-38):

Although Evans offered no explanation for this remarkable change in
outlook, one letter revealed that he had "made some interesting
additions" to his geologic collection during this trip. Indeed he had!
The most interesting of these, I contend, was a small meteorite.
To ascertain the true origin of the meteorite, I compared printed
accounts of its physical appearance, degree of weathering, and chemical
composition against those of the other pallasites discovered in Evans's
day. I concluded that the Port Orford specimen was actually a piece of
the Imilac meteorite, which had been found in the Atacama Desert in
Chile around 1820-22.
This possibility had been tentatively raised earlier by meteoriticists
but had been dismissed for various reasons. In the first place, the Port
Orford meteorite has a well-preserved black fusion crust on it, but
Imilac specimens do not. Second, there are some differences between the
trace-element levels in the metal of the two meteorites.
But my research revealed that R.A. Philippi, who had visited the Imilac
strewnfield in 1854, had described the surfaces of the small meteorites
he found as "very black." Moreover, the Smithsonian received an Imilac
specimen collected as late as 1973 that has a "well-preserved fusion
crust as is observed on the Port Orford specimen."
My research further convinced me of the important role played by the
llimaes meteorite. llimaes is another pallasite found in the Atacama
Desert about 50 years after Imilac and 170 miles farther south. Now in
the mineral collection of the School of Mines, Copiapó, Chile, the main
portion of this specimen is also covered by a thick black fusion crust.
Although llimaes and Imilac also show differences in their trace-element
levels, meteoriticists now consider them to be part of the same fall.
When I initially compared the trace-element levels in Port Orford and
Imilac, I found it difficult to assess their differences. Yet published
data on Ilimaes showed that it is as similar to Imilac as it is to Port
Orford!
If it was justifiable to consider Imilac and llimaes a pair, then it was
also justifiable to pair Port Orford with Ilimaes and thus with lmilac
as well.
Thousands of small fragments were produced in the shower that yielded
Imilac and its kin. In the second quarter of the 19th century, many of
these passed through Panama on their way to various museums and
collectors in North America and Europe.
Putting all the pieces of the Port Orford puzzle together, I concluded
that Evans acquired a small, well-preserved, curio-size specimen of the
Imilac meteorite when he crossed the Isthmus of Panama in the fall of
1858 on his final trip from Oregon to Washington. With it he perpetrated
a deliberate and elaborate hoax which he hoped would result in
congressional funds that would rescue him from his crushing debt of
professional and private debt.
Recently, extensive metallographic and mineralogical examinations of
Port Orford and specimens from the Imilac shower were carried out by
R.S. Clarke, Jr., of the Smithsonian and V.E. Buchwald of the Technical
University of Denmark. They also conclude that the Port Orford meteorite
is indeed an Imilac fragment, and that Evans used it as bait in a
deliberate hoax.

When not looking for lost meteorites, Howard Plotkin teaches the history
of science at the University of Western Ontario. The full account of his
investigation of the Port Orford meteorite and the Clarke-Buchwald
technical investigation appears in Smithsonian Contributions to the
Earth Sciences, No. 31, 1993. A limited number of copies are available
from R.S. Clarke, Division of Meteorite MRC 119, National Museum of
Natural History, Smithsonian Institution, Washington, DC 20560.


Best wishes,

Bernd

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