[meteorite-list] Tambo Quemado phosphates

From: bernd.pauli_at_paulinet.de <bernd.pauli_at_meteoritecentral.com>
Date: Sun Aug 22 12:28:01 2004
Message-ID: <DIIE.0000003100002701_at_paulinet.de>

Hello List,

For those who are interested, I just found this:

OLSEN E.J. et al. (1999) The phosphates of IIIAB iron
meteorites (MAPS 34-2, 1999, pp. 285-300, p. 285, abstract):

Thirteen phosphate minerals are found in IIIAB iron meteorites. Four
of these (sarcopside, graftonite, johnsomervilleite, and galileiite)
constitute the majority of occurrences. The IIIB iron meteorites are
confined to occurrences of o n l y these four phosphates. The IIIA
iron meteorites may contain one or more of these four phases; they
may also contain other rarer phosphates, and silica (in two instances)
and a silicate rock (in one instance).

OLSEN E.J. et al. (1999) The phosphates of IIIAB iron meteorites
(MAPS 34-2, 1999, pp. 285-300, p. 292, Other IIIAB irons):

Samples thought to contain phosphates were collected from Delegate
IIIB (Anom), Henbury IIIA, Plymouth IIIA, Puente del Zacate IIIA,
and Tambo Quemado IIIB. Delegate contained only chromite, Henbury
only daubreelite; Plymouth contained terrestrial contamination (clay
minerals, feldspar, quartz); Puente del Zacate contained an inclusion
of silicate rock (Olsen et al., 1996), the only occurrence known of a
silicate assemblage in a IIIAB iron*; Tambo Quemado contained extra-
ordinary silicophosphates created by anthropogenic heating of the
meteorite (Olsen et al., 1993).

The noteworthy passages here are:

- terrestrial contamination (clay minerals, feldspar, quartz) in Plymouth
- an inclusion of silicate rock in Puente del Zacate
- the only occurrence known of a silicate assemblage in a IIIAB iron

* plus the two possible occurrences (Avoca, Grant) Buchwald mentions,
  plus maybe my weird inclusion in TQ would raise the number to two (or
  to four). But, perhaps it is only "anthropogenic" - i.e. terrestrial
  and caused by man.

Best wishes,

Bernd
Received on Sun 22 Aug 2004 12:27:58 PM PDT