Paul H. Benoit and Derek W.G. Sears
Cosmochemistry Group
University of Arkansas
Fayetteville, AR 72701 USA
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 or 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 |
---|---|---|
ALH 97101 |
H5 |
0.7 ± 0.1 |
ALH 97102 |
H5 |
39.4 ± 0.3 |
GRA 98186 |
H6 |
39.8 ± 0.5 |
SCO 98200 |
L4 |
3.5 ± 0.1 |
ALH 97100 |
L6 |
22.5 ± 0.1 |
LEW 97204 |
L6 |
12.4 ± 0.1 |
LEW 97205 |
L6 |
11.6 ± 0.1 |
LEW 97207 |
L6 |
9.7 ± 0.1 |
LEW 97210 |
L6 |
12.3 ± 0.1 |
LEW 97212 |
L6 |
9 ± 1 |
SCO 98201 |
L6 |
6.9 ± 0.2 |
LEW 97213 |
LL5 |
5.5 ± 0.1 |
QUE 97805 |
LL5 |
0.4 ± 0.1 |
QUE 97807 |
LL5 |
4.0 ± 0.1 |
QUE 97811 |
LL5 |
17.0 ± 0.1 |
QUE 97840 |
LL5 |
3.2 ± 0.1 |
LEW 97203 |
LL6 |
7.6 ± 0.1 |
LEW 97206 |
LL6 |
4.9 ± 0.1 |
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.
LEW 97207 (L6) has very low TL sensitivity and may be highly shocked.
Pairings suggested by TL data: