[meteorite-list] ALOD vs ACAP

[bernd.pauli at paulinet.de]

Greg inquired: "What is the average grain size for the ACAP grouping being discussed"

HUTCHISON R. (2004) Meteorites: A Petrologic, Chemical, and Isotopic
Synthesis (Cambridge Planetary Science Series, pp. 506)-Excerpt, p. 252:

Table 8.2 Properties of primitive achondrite groups
Grain size:
Acapulcoites: 150-230µm (= 0.15-0.23 mm)
Lodranites: 340-700µm (= 0.34-0.70 mm)

Well, as for my NWA 2871 thin section, I find grains measuring 0.42, 0.52, 0.59 mm.
That would be an average grain size of 0.51 mm for these three counts - well within
the range for lodranites but bulk rock composition (see my previous post to the List)
may speak a different language.

I'm still waiting for John Kashuba and Roger Warin to chime in. Friday, May 18, 2007,
Roger and myself exchanged emails re: Tafassasset and NWA 2871 and Roger wrote:

«Voilà comme je définissais l'acapulcoite NWA 2871: ... »

Well, let's leave it up to Roger what exactly he wrote but I am sure several list
members would appreciate his assessment very much - Roger are you out there?


Best wishes,

Bernd




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