Jason Slinker, Paul Benoit, and Derek Sears
Cosmochemistry Group
Dept. of Chemistry and Biochemistry
University of Arkansas
Fayetteville, AR 72701
The measurement and data reduction methods were described by Hasan et al. (1987, Proc. 17th LPSC E703-E709); 1989, LPSC XX, 383-384). For meteorites whose TL lies between 5 and 100 krad, the natural TL is related primarily to terrestrial history. Samples with NTL <5 krad have TL levels below that which can reasonably be ascribed to long terrestrial ages. Such meteorites have had their TL lowered by heating within the last million years of so by close solar passage, shock heating, or atmospheric entry, exacerbated in the case of some achondrites by anomalous fading. We suggest meteorites with NTL >100 krad are candidates for unusual orbital/thermal histories (Benoit and Sears, 1993, EPSL, 120, 463-471).
Sample | Class | Natural TL [krad at 250° C] |
---|---|---|
EET96135 |
EH4-5 |
5±2 |
EET96058 |
H5 |
2.1±0.1 |
EET96134 |
H5 |
1.6±0.2 |
EET96139 |
H6 |
74.8±0.3 |
EET96186 |
H6 |
96.4±0.2 |
MET96503 |
L3.6 |
11.0±6.0 |
MET96504 |
L5 |
60.4±0.2 |
EET96130 |
L6 |
16.5±0.1 |
EET96132 |
L6 |
61.8±0.6 |
EET96136 |
L6 |
104.0±0.1 |
EET96140 |
L6 |
1.2±0.2 |
EET96270 |
L6 |
7.7±0.1 |
EET96271 |
L6 |
30.4±0.1 |
EET96273 |
L6 |
10.6±0.1 |
EET96274 |
L6 |
191±2 |
EET96313 |
L6 |
26.2±0.6 |
EET96313 |
L6 |
57.3±0.6 |
EET96316 |
L6 |
78±2 |
EET96330 |
L6 |
61.6±0.3 |
EET96332 |
L6 |
54.4±0.1 |
EET96333 |
L6 |
4±4 |
EET96340 |
L6 |
29.6±0.1 |
EET96351 |
L6 |
0.8±0.5 |
MET96501 |
L6 |
35.6±0.1 |
MET96502 |
L6 |
0.3±0.1 |
EET96137 |
LL6 |
10.4±0.1 |
EET96293 |
URE |
2±1 |
The quoted uncertainties are the standard deviations shown by replicate measurements on a single aliquot.
COMMENTS: The following comments are based on natural TL data, TL sensitivity, the shape of the induced TL glow curve, classifications, and JSC and Arkansas sample descriptions.
EET96333 has very low TL sensitivity relative to Dhajala, and is probably highly shocked.
TL sensitivity for MET96503 is similar to a type 3.1. It is possible this meteorite is highly shocked.
1.Pairings suggested by TL data: