Natural Thermoluminescence (NTL) Data for Antarctic Meteorites

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 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 certain achondrite classes by "anomalous fading".

Sample Class NTL [krad at 250° C]
GRO 95535HOW11±1
QUE 94500H536.0±0.3
GRO 95544L31
GRO 95545L31
QUE 94473L516.0±0.1
QUE 94477L51.9±0.2
QUE 94714L564.8±0.1
QUE 94716L54.2±0.2
QUE 94623L64.4±0.1
QUE 94719L6>21.4±0.1

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 glow curve, classifications, and JSC and Arkansas group sample descriptions.

GRO 95544 and GRO 95545 (L3) have very low induced TL sensitivities (0.003 and 0.006 relative to Dhajala H3.8, respectively) and are either type 3.1 or are highly shocked.

GRO 95535 (HOW) has low induced TL sensitivity (0.17+-0.02 relative to Dhajala H3.8) compared to most howardites, perhaps indicative that it is rich in diogenitic material (GCA 55, 3831-3844).

1. Pairings (Confirmations of pairings):

2. Pairings suggested by TL data: