Geology Reference
In-Depth Information
LL5 chondrite shower
1282.5 g
Found January 5, 1991
12 × 9 × 6 cm
Weathering = A/B
Meteorite showers have been documented in a number of cases and have
allowed estimates to be made of impactor size, age, and dynamics.
Antarctic meteorite showers are not common but have been documented
on a small scale. Any new examples can provide important information
about pairing, statistical evaluation of dense collection areas
QUE90201
1cm
,0
,4
W
,3
2mm
QUE 90201
(a)
(b)
7
1. 5
6
0
0
93021
5
93021
100
1. 0
50
93050
97028
4
200
97013
100
0.8
97013
150
3
0.6
2
0.4
5
7
4
6 8 0
36
CI (metal) [dpm kg
-1
]
20
30
0.8
1
3
10
Be (metal) [dpm kg
-1
]
Plate 9
MiNERALogy
SigNiFiCANCE
Members of this shower have properties typical of L
(e.g., pyroxene composition) and LL chondrites (e.g.,
metal abundance and composition), as well as properties
intermediate between the L and LL groups (e.g., olivine
composition), and are thus best described as L⁄LL5
chondrites.
Samples span six field seasons: 1990, 1994, 1995, 1997,
1999, and 2002. The measured radionuclide concentra-
tions of
10
Be,
36
Cl, and
41
Ca (bottom, [34]) in the metal
and stone fractions of QUE 90201 indicate an age of
100-150 Ka and irradiation in an object with a preatmo-
spheric radius of approximately 150 cm, representing one
of the largest chondrites known so far. The QUE 90201
shower includes up to 2000 fragments with a total recov-
ered mass of 60-70 kg, <1% of the preatmospheric mass
of approximately 50,000 kg.
References [34]
