[meteorite-list] Slickensides

From: Bernd Pauli HD <bernd.pauli_at_meteoritecentral.com>
Date: Thu Apr 22 10:18:29 2004
Message-ID: <3E568CC3.5AFABCD9_at_lehrer.uni-karlsruhe.de>

Bonsoir Michel, hello List,

> It is still not very clear to me if these features are
> made in outer space or the result of hard landing.

Here are some interesting tidbits:

BUCHWALD V.F. (1975) Iron Meteorites
(UCLA, 1975, Vol.3, excerpts from pp. 1128):

Figure 1629. Sikhote-Alin (U.S.N.M. no. 1708B). A distorted
fragment of 1.28 kg produced during the impact with the frozen
ground. Slicken-sided surfaces alternate with twisted and ragged
portions.

The smaller specimen in the U.S. National Museum is a torn fragment
of 1.3 kg with ragged edges. It is one out of approximately 200 similar
fragments, totaling 300 kg and excavated in 1948 from pit No. 28 (ibid.,
Volume 1:180, Volume 2:193). The external shape clearly shows how the
major fractures formed upon impact and followed the schreibersite-loaded
grain boundaries and the schreibersite-troilite inclusions. The fracture
faces are rich in distortions and ridged, semi-polished slickensides
c r e a t e d a t t h e m o m e n t o f b r e a k u p. Similar
heavily gouged surfaces are present on many Imilac samples.

BUCHWALD, V.F. (1975) Handbook of Iron Meteorites, Volume 2, p. 643:

Henbury

Several other specimens show violent deformations like those of No.
882A, e.g., No. 943 of 3.4 kg, which is a flat explosion fragment with
razor-sharp edges, locally overturned. This particular specimen has a
slickensided surface f r o m s h e a r - r u p t u r i n g, and it is
covered by a thin fusion crust formed when it was hurled away from the
impact site. The whole specimen is unique but corresponds closely to the
numerous Imilac specimens with slickensided surfaces; see page 1398.


Best regards,

Bernd
Received on Fri 21 Feb 2003 03:32:03 PM PST