[meteorite-list] Acapulcoites are the third most common meteoritetype.

From: David Weir <dgweir_at_meteoritecentral.com>
Date: Wed Feb 15 15:22:50 2006
Message-ID: <43F38D93.8020202_at_earthlink.net>

Hello Martin,

As for NWA 725, here are the details as Stan shared them with me:

Recent O-isotopic analysis of a probable paired stone (number pending)
by the Open University resolves the material clearly within the
winonaite field:
"In particular, the D17O value of -0.431 is in reasonable agreement with
the mean value of -0.48 for the winonaite-IAB iron-IIICD iron group
determined by Clayton and Mayeda (1996)."
In addition, when plotted on a diagram comparing the D17O-isotopic value
vs. Fa mol% in olivine (Rumble, III et al., 2005), NWA 725 (Fa 6.1;
D17O-isotopic value taken from the paired stone [Turecki, 2005; pers.
comm.]) and the winonaites NWA 1463 (Fa 7.4; D17O = -0.45&#137;), NWA
1457 (Fa 5; D17O = -0.40 &#177;0.03&#137;), and NWA 1058 (Fa 6.5; D17O =
-0.53&#137;) all plot very close together within the winonaite field.
The inference can thus be made that NWA 725 is actually a winonaite,
likely paired with the primitive winonaites NWA 1463 and 1058.

David
Received on Wed 15 Feb 2006 03:22:43 PM PST