Geology Reference
In-Depth Information
Basaltic shergottite
12.02 g
Found December 16, 1994
2.3 × 2.0 × 1.5 cm
Weathering Be
Basaltic shergottites are more evolved basalts such as Shergotty and Zagami
that are linked to Mars by their age, o isotopes, and noble gas content.
Studies of basaltic shergottites have revealed information about the
production of magmas on Mars, and efforts have been made to understand
the links between olivine phyric shergottites, basaltic shergottites, and
lherzolitic shergottites to better understand the magmatic history of Mars.
7.0
y = 0.715x + 4.2467
R
2
= 0.9992
4000
6.0
DSc QUE exp.
5.0
DCr QUE exp.
V
3000
4.0
DV QUE exp.
QUE 94201
3.0
Cr
y = -0.635x + 2.86
R
2
= 09998
2000
2.0
y = 0.045x + 1. 3
R
2
= 0.75
1.0
Sc
1000
0.0
0
0.2
0.4
0.6
0.8
1
-2
-1
0
1
2
3
4
H
2
O content (wt.%)
fO
2
relative to IW
Plate 71
MiNERALogy
SigNiFiCANCE
QUE 94201 exhibits a medium-grained (1-5 mm) texture
dominated by plagioclase and pyroxene. Plagioclase is
normally zoned (An
68
to An
57
) and pyroxene is adjacent
to and sometimes enclosed by plagioclase. Pyroxene
consists of pigeonite and augite; pigeonite exhibits
normal Mg-Fe-Ca igneous zoning (from Wo
9
En
60
Fs
31
to
Wo
16
En
1
Fs
83
), whereas the augite compositions are
bimodal Wo
30
En
45
Fs
25
and Wo
40
En
2
Fs
58
.
QUE 94201 is one of the most reduced basaltic rocks
among the martian meteorites, near the iW buffer (right,
[710]), and represents an end member of the known
oxidation states within the martian interior. QUE 94201
is also a member of the isotopically depleted shergottites,
which define an important interior reservoir of the mantle
and crust. in addition, this sample contains hydrous min-
erals (phosphate) and evaporites. These minerals provide
information about martian volatiles (H
2
o, Co
2
, and S
2
)
(left, [714]) and igneous processes in martian magmas, as
well as alteration processes at the martian surface.
References [701-722]
