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O'Malley 022
Basic information Name: O'Malley 022
     This is an OFFICIAL meteorite name.
Abbreviation: There is no official abbreviation for this meteorite.
Observed fall: No
Year found: 2012
Country: Australia
Mass:help 107.6 g
Meteoritical Bulletin:  MB 108  (2020)  L6
Recommended:  L6    [explanation]

This is 1 of 12057 approved meteorites (plus 6 unapproved names) classified as L6.   [show all]
Search for other: L chondrites, L chondrites (type 4-7), Ordinary chondrites, and Ordinary chondrites (type 4-7)
Comments: Approved 23 Jan 2019
Writeup from MB 108:

O’Malley 022        30°37’53.4"S, 131°29’53.5"E

South Australia, Australia

Find: 17 May 2012

Classification: Ordinary chondrite (L6)

History: Found by A. Tait on desert caliche between claypans.

Physical characteristics: Half-fist sized dark red-brown sample with 95% smooth fusion crust, a small amount of lichen attached.

Petrography: (L. Bowlt) Chondrules range in size up to 1.2 mm diameter, have diffuse boundaries and sit in a highly recrystallised matrix. Mineralogy includes olivine, pyroxene, plagioclase (many plagioclase grains exceed 50 μm), Fe-Ni metal and troilite. Chondrule types include BO, RP, PO, PP, POP. Metal and troilite grains are large, both ranging up to 1 mm in size. Plagioclase is abundant (20-30%) and some has been converted to maskelynite. Olivine grains show undulose extinction, mosaicism and contain distinct perpendicular sets of shock lamellae. Moderate oxidation of metal and troilite has occurred with 20-25% of the grains affected. Given that most oxidation occurs as rims on the metals/sulfides and there are no oxide veins, estimates of original percentages of metal and troilite are approximately 1-3% and 5-15% respectively.

Geochemistry: (L. Bowlt, Monash) Microprobe analyses show that olivine and pyroxene compositions are uniform: olivine Fa23.1-24.3, mean= Fa23.4, std=0.65, n=6; Low-Ca pyroxene Fs18.4-19.9 , mean= Fs19.3, std=0.64 , n=6.

Classification: Ordinary Chondrite (L6, S4, W3)

Data from:
  Table 0
  Line 0:
State/Prov/County:South Australia
Origin or pseudonym:Nullarbor Plain
Date:17 May 2012
Mass (g):107.6
Shock stage:S4
Weathering grade:W2
Fayalite (mol%):23.4±0.7 (n=6)
Ferrosilite (mol%):19.3±0.6 (n=6)
Wollastonite (mol%):1.7
Classifier:L. J. Bowlt, Monash
Type spec mass (g):104.2
Type spec location:Monash
Main mass:Monash
Finder:A. Tait
Comments:Submitted by A. Tomkins
   and collections
Monash: Building 28 School of Geosciences Monash University Victoria 3800 Australia, Australia (institutional address; updated 12 Dec 2012)
References: Published in Meteoritical Bulletin, no. 108 (2020) Meteorit. Planet. Sci. 55, 1146-1150
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     Recommended::   (30° 37' 53"S, 131° 29' 53"E)

     This is 1 of 240 approved meteorites from South Australia, Australia (plus 3 unapproved names) (plus 4 impact craters)
     This is 1 of 717 approved meteorites from Australia (plus 46 unapproved names) (plus 27 impact craters)
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