[meteorite-list] Santa Rosa - Part 1 of 2

From: Bernd Pauli HD <bernd.pauli_at_meteoritecentral.com>
Date: Thu Apr 22 09:41:10 2004
Message-ID: <3A8AE339.52F1C820_at_lehrer1.rz.uni-karlsruhe.de>

Dan asked:

> Can anyone give me any information on the Santa Rosa iron
> meteorite? Is this another name for a known meteorite?

Mike Farmer responded:

> It is the iron from Colombia, I believe the main mass is in Chicago.

Hello Dan, Mike, and List,

Here is what Buchwald writes in his famous Handbook of Iron Meteorites:

BUCHWALD V.F. (1975) Handbook of Iron Meteorites, Vol. 3, pp. 1075-1080,
excerpts:

Santa Rosa, Boyacá, Colombia
05° 55' N, 072° 59' W; 2,750 m
Anomalous. Shock-reheated.
Polycrystalline iron with cohenite and graphite.

6.74% Ni - 0.51% Co - 0.36% P - 0.19% C - 0.3% S - 52 ppm Ga - 222 ppm
Ge - 0.07 ppm Ir.

Numerous specimens which were recovered in early days have been
artificially reheated to about 1000° C, and are often labeled Rasgata.

History

The main mass of 612.5 kg was discovered in 1810 on a hill named
Tocavita about a mile east of the main square of Santa Rosa de Viterbo,
a small town in the Andes Mountains 175 km northeast of Bogotá. Two
small individuals of 681 gr and 561 gr and several unspecified fragments
were found in the following years on the same hill. Two larger
individuals of 41 kg and 22 kg were obtained from a miner in a village,
125 km farther south in the region of Rasgata; but these are, no doubt,
transported fragments. Humboldt (1823) announced the discovery, and
Rivero & Boussingault (1824) described and analyzed the specimens.
Partsch (1843) and Wöhler & Partsch (1852) also examined the material
and presented lithographs of etched sections. Many other examinations
appeared, but the confusion was considerable, because:

(i) it was not recognized that several wrought iron specimens
    were included in collections as authentic material;
(ii) it was not realized that a large part of the material received in
     Europe had been artificially reheated with the result that the
     structure had become very anomalous- and
(iii) the chemical analyses of the nineteenth century were generally
      accredited with a much too high precision when, in fact, they
      were of a highly vacillating quality.

Cohen (1905), who published a very thorough study, thus worked only
with artificially heat-treated material without knowing it himself.
Ward (1907), in an attempt to clear up the mess, made an adventurous
journey to the disputed place, Santa Rosa, and purchased the 612 kg
main mass which at that time had been exhibited for a generation as
a beloved item on a pillar at the market place. While he was not
allowed to export the whole meteorite, he did secure a 150 kg endpiece
which was later cut and distributed*.
Ramirez (1949) gave a summary of the history and geography of the
problem as seen in Colombia. He identified the locality, as did
Ward, as the somewhat elevated terrain 1-2 km east of the main square
which is now the property of the Jesuit Novitiate in Colombia.
"On this property and in the surrounding territory since 1810 until the
present day, several meteorites, both large and small, have been found
buried in the ground. These meteorites are to be found mostly in private
collections of Colombia."
The two largest specimens recovered in recent years (38.4 kg found in
1926, and 100.5 kg found in 1942, 10-15 km east of Santa Rosa) are now
in Bogotá, Quite recently a mass of 8 kg, has been recorded as being in
the Jesuit Monastery at Santa Rosa.
Thus, Santa Rosa is an important shower, totaling at least 825 kg and
apparently covering an area 10-15 km long. Only the first found, small
masses, Nos. 2-6, appear to have been reheated artificially; but these
were the very masses which were more or less distributed in the 19th
century and which caused the confusion.
Buchwald & Wasson (1968) examined a large number of specimens
from various collections, presented new analyses and numerous
photomicrographs of both authentic material and - for comparison
- of artificially reheated specimens in Vienna, London and Berlin
and of pseudometeorites labeled Santa Rosa.

* cp. PALMER TOM (2000)Henry Augustus Ward and His Meteorites
(M!, May 2000, Vol. 6, No. 2, pp. 39-40). The article features a photo
showing Henry Ward with the Santa Rosa mass in the market place.
Received on Wed 14 Feb 2001 02:57:45 PM PST