Geology Reference
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,25
,24
,26
Clast b
,25
,24
Undocumented chips
from region of break
,27 to ,32 ,59
Clast a
,26
,0
,0
T 1
Exploded view
ALH A81005
Stage II processing, 1983
,25
,24
ALH A81005
Top piece
,26
(below ,0)
Figure 3.8. Stage II processing which generated splits 24, 25, 26, 59 and several smaller pieces for allocations (NASA photo
S83-34612 and S83-34613).
,36
and pyroxene, with about 10% of very large crystals of
olivine. In hand sample, the light green to yellow to white
olivine crystals stand out clearly. In comparison, lithology
B is coarser grained, contains no megacrysts, and has
elongate plagioclase (maskelynite) crystals as well as
pigeonite. The differences are illustrated even more so
when looking at the contact between the two in either
hand sample or thin section (Figure  3.9; Plate 70).
Confusing Lithology A for Lithology B is possible if one
is looking at only one lithology without a reference piece
of both lithologies. Also, if olivine is not present on any
given piece of Lithology A, it is possible to confuse these
in hand sample, given the similar color and overall tex-
ture of the matrix.
Lithology B is only present at one end of the meteorite,
and more specifically when looking at the oriented photos
from the meteorite laboratory, it is on the end designated
“East” [see McSween et al ., 2014 (this volume)]. An estimate
may be made of the mass of Lithology B by assuming an
EET A79001, 2
,21
,33
,30
,35
,31
1cm
,32
,34
Figure 3.9. Photograph of a slab ,2 cut from EET A79001,
exposing the contact between Lithology A and B (NASA photo
S81-25271).
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