Geology Reference
In-Depth Information
5/1982
31.3 g
,0
(,0 = 26.899 g after)
3.39 g
3.77g
,2 PB
0.79 g
,5
,1
,3 ,4 ,8 ,9 ,22 ,23 ,80 ,81
,7 PB
,10
,11
,12
,13 ,14
,15 ,16
,17
,18 ,19 ,20
,79
6/1983
~23.5 g
Photo S83-34612
(,0 = 10.873g after)
,0
1.14 g
3.4 g
~0.2g
~0.3g
~0.3g
~0.36g
~1.02g
~0.2g
,25
,59
~0.2g
,26
,27
,28
,29
,30
,31
,32
Photo S83-34613
,41
,74
,75
,63
,42
,64
,65
,73
,66
,83
,84
,43
,44
,45
,46
,47
,48
,33
,34
,35
,36
,37
,38
,39
,40
,50
,51
,24
4.4 g
,69
,70
,71
,72
9/83-7/84
,49
,56
,57
,52
,53
,54
,55
,58
,59
,60
,61
,62
Figure 3.7.
Genealogy of ALH A81005 showing processing in two main stages (I and II), as well as later (post-1984) processing.
Ovals are potted butts used to make thin sections; square is a chip.
would be fair yet expedient. This process is described in
some detail by
Cassidy
[2003] and set a precedent for how
precious meteorite samples would be allocated. A sum-
mary of how the sample was divided (in two main stages)
is presented in Figures 3.6, 3.7, and 3.8.
tinue to provide important information about the geologic
history of Mars, and EET A79001 is the most highly
requested sample in the U.S. Antarctic meteorite collec-
tion, having received close to 300 requests since 1980.
Now we will focus on the more rare Lithology B, esti-
mated to have originally been ~350 g of the total mass
of the meteorite (<5% of total mass of the meteorite). It
is of interest to those studying the magmatic history of
Mars and the connection between the various basaltic
rocks represented in the world's martian meteorite collec-
tions. Lithology B illustrates the challenges of curating a
more rare lithology in the face of a multitude of requests
for scientific studies. Using this meteorite's data packs,
photographic information, and published studies, an
assessment will be made of how much Lithology B
material has been utilized to enable new discoveries, and
how much remains for future use.
Lithology B is best recognized with respect to the main
lithology of EET A79001: Lithology A. Lithology A con-
sists of a fine-grained matrix of plagioclase (maskelynite)
3.3.2. Allocation History of EET A79001 Lithology B:
An Update and Synthesis (Plate 70)
Martian meteorite Elephant Moraine (EET) A79001,
weighing 7.9 kg, was discovered in the Elephant Moraine
region of the Transantarctic Mountains during the 1979-
1980 field season. Having three distinct lithologies, olivine
megacryst-bearing main lithology (A), a basaltic textured
minor lithology (B), and many small glassy inclusions
(C), it was recognized to have some affinity with Shergotty,
which is texturally similar to Lithology B [
Score et al
.,
1982], and it became one of the important links between
Mars and martian meteorites [
Bogard and Johnson
, 1983;
Bogard et al
., 1984]. The three distinct lithologies con-
