BEALIBA METEORITE 
9 
temperature heat source, such as an oxy-acety- 
lene flame, by the finder. 
PETROGRAPHY AND MINERALOGY 
In thin section, the Bealiba meteorite shows 
plentiful but mostly poorly defined chondrules 
up to 2.5 mm across, together with irregular met¬ 
allic grains up to 2.5 mm across, in an exten¬ 
sively recrystallised granular matrix which has 
been heavily stained with iron oxides. The main 
groundmass minerals are olivine, with less abun¬ 
dant orthopyroxene and interstitial oligoclase. 
Glass is absent. The chondrules may be fine¬ 
grained or barred olivine or orthopyroxene 
types, with minor clinopyroxene and interstitial 
sodian feldspar. Others consist of a distinct 
annulus of olivine and a core of rounded olivine 
grains in optical continuity (Fig. 4). 
Microprobe analysis (Table 1) showed the 
olivine in both the groundmass and chondrules 
to be quite uniform in composition. Six analyses 
gave an average formula of Fo 74 6 Fa 2 4 . 9 Te 0 .5 
(mol%). The orthopyroxene is Mg-rich (“bron- 
zite”)with an average composition expressed by 
En 77 Fs 2 | > 5 Wo 15 (average of 5 analyses), and the 
uncommon clinopyroxene is diopside (Fig. 5). 
The interstitial oligoclase is Ab 83 An n Or 6 . 
The main metallic minerals in the meteorite 
are kamacite, troilite and taenite, which together 
Fig. 4. Olivine chondrule 1 mm in diameter, showing 
distinct annular rim and etched core in optical con¬ 
tinuity. 
constitute about 5% of the stone. Kamacite oc¬ 
curs as irregular grains up to 2 mm across, 
showing as creamish white and highly reflective 
in incident light. Taenite is not as common and 
generally forms smaller grains, although some of 
the larger grains show the two minerals in sharp 
contact. The taenite may be distinguished by its 
slightly greyer colour, but unless the two min¬ 
erals are in contact they cannot easily be dis¬ 
tinguished optically. Troilite is as common as 
kamacite and forms irregular pale brownish 
1 
2 
3 
4 
5 
Si0 2 
37.76 
64.78 
55.40 
54.07 
— 
Ti0 2 
0.02 
— 
0.26 
0.55 
3.31 
Ab0 3 
— 
19.78 
0.15 
0.46 
6.21 
Fe 2 0 3 
_ 
1.83 
0.56 
— 
— 
Cr 2 0 3 
_ 
— 
0.13 
0.64 
54.50 
NiO 
_ 
— 
0.06 
0.08 
— 
FeO 
23.10 
— 
14.54 
5.25 
31.65 
MnO 
0.41 
— 
0.38 
0.23 
— 
MgO 
38.21 
0.87 
28.14 
16.19 
2.27 
CaO 
— 
2.16 
1.01 
22.07 
— 
Na 2 0 
_ 
9.70 
— 
0.60 
— 
K 2 0 
— 
1.12 
— 
— 
— 
Total 
1. Olivine (chondrule rim) 
2 . Oligoclase (groundmass) 
3. Orthopyroxene (g’mass) 
4. Diopside (in chondrule) 
5. Chromite (groundmass) 
99.50 
Fo 74 4 Fa 25 2 Te 04 
Abg 3 4 An 103 Or 6 3 
Fn 75 . 5 Fs 72 . 5 W 07 0 
Fn 4 6 .!Wo 4 5 2 Fs 8 . 7 
100.24 
100.53 
100.14 
97.94 
Table 1. Microprobe analyses of non-metallic minerals in the Bealiba Meteorite. Analyses obtained using 
Cameca and Jeol microprobes at 15 kV and specimen current 0.02 pA. Standards included corundum (Al), 
wollastonite (Ca, Si), pure metals (Cr, Ni, Mn), hematite (Fe), jadeite (Na), rutile (Ti) and synthetic KTa (K). Fe 
partitioned by stoichiometry. 
