The Corowa meteorite
was first recognised in 1964 however it was discovered prior to this
year. It was found near Corowa, New South Wales, Australia which is a rural town on Australia's famous Murray River
and
is actually the border of New South Wales and Victoria. A single
mass weighing 11.3kg was plowed up just 6km from the township. A
portion of the meteorite was cut with an oxy-acetylene torch and examined
by the finder while at a later date, another section was cut
using a power
hacksaw and examined in detail by Baker et al, (1964). Renowned
iron meteoriticist, Vagn Buchwald, also studied and wrote about
the Corowa iron in his 1975, "Handbook of Iron Meteorites".
Corowa has been classified as a very rare
Anomalous Plessitic Octahedrite and
allocated into the rare IIF group which has only five meteorites
known in total. Corowa also has a high nickel content of over
13.1%. Vagn Buchwald stated in the previously mentioned study
that "etched sections show that Corowa is a plessitic
octahedrite where scattered, pointed kamacite spindles cover
about 20% by area, while taenite and plessite, with more
numerous but much finer kamacite spindles, cover 80%." Plessite
(or plessitic) is not a mineral as such but rather a fine
grained mixture of Kamacite and Taenite.
Another point raised by Buchwald which is
somewhat evident in the photographs below is that "troilite
occurs as a few large nodules, 5-10mm across, and as small
blebs, widely disseminated in the metallic matrix, according to
a sulphur print in Baker et al. (1964). The troilite is shock
melted and solidified to fine grained aggregates from which
minute veinlets radiate through adjacent schreibersite and a
portion of the metal. Small angular fragments of schreibersite
may be found dispersed in the troilite melt." The large
irregularly shaped troilite
nodule pictured in the first image measures 21.5mm x 7.5mm
and 8.5mm x 7mm in the second image.
The specimen below is a 70.6g Partslice,
representing an end one-third of a Complete Slice taken from the Main
Mass. This specimen is part of the Meteorites Australia
Collection (MA.05.0111).