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O'Malley 020
Basic information Name: O'Malley 020
     This is an OFFICIAL meteorite name.
Abbreviation: There is no official abbreviation for this meteorite.
Observed fall: No
Year found: 2010
Country: Australia
Mass:help 13 g
Meteoritical Bulletin:  MB 102  (2013)  H4
Recommended:  H4    [explanation]

This is 1 of 6388 approved meteorites (plus 2 unapproved names) classified as H4.   [show all]
Search for other: H chondrites, H chondrites (type 4-7), Ordinary chondrites, and Ordinary chondrites (type 4-7)
Comments: Approved 28 Jan 2013
Writeup from MB 102:

O’Malley 020        30°34’21.7"S, 131°28’51.4"E

South Australia, Australia

Found: 14 Apr 2010

Classification: Ordinary chondrite (H4)

History: Single piece found by K. Bell on the Nullarbor Plain.

Physical characteristics: Single stone lacking fusion crust.

Petrography: (A. Tomkins, Monash) Well-defined chondrules (to 1.5 mm) in an optically opaque matrix. Chondrule mesostases very finely recrystalized (<1 μm). Plagioclase to <5 μm in some chondrules. Chondrule types include RP, POP, PP, BO, PO and rare devitrified glass chondrules. Fe-Ni metal grains are almost completely destroyed by weathering, whereas troilite grains are largely intact. The weathering has generated a fine network of iron oxides within the matrix. Most olivine grains show sharp optical extinction, although some have undulose extinction.

Geochemistry: (A. Tomkins, Monash) Microprobe analyses show that pyroxene composition are variable; from a small number of analyses olivine appears uniform: olivine Fa19.7-20.5, mean=20.2 mol%, std=0.28, n=6; Low-Ca pyroxene Fs16.4-19.9, mean=17.9 mol%, std=1.50, n=4.

Classification: Ordinary chondrite (H3, S2, W4). The type 4 classification is based on the optically opaque matrix and very fine scale of glass recrystallization.

Data from:
  Table 0
  Line 0:
State/Prov/County:South Australia
Origin or pseudonym:Nullarbor Plain
Date:14 Apr 2010
Mass (g):13
Shock stage:S2
Weathering grade:W4
Fayalite (mol%):20.2±0.3
Ferrosilite (mol%):17.9±1.5
Wollastonite (mol%):1.33
Classifier:A. Tomkins, Monash
Type spec mass (g):6.1
Type spec location:Monash
Main mass:Monash
Finder:K. Bell
Comments:Submitted by A. Tomkins, B. Schaefer, M. Pankhurst, K. Bell
   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. 102, MAPS 50, 1662, September 2015
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     Recommended::   (30° 34' 22"S, 131° 28' 51"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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