Paul Benoit, Joyce Roth, Hazel Sears, 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 past million years or so (by close solar passage, shock heating, or atmospheric entry), exacerbated, in the case of certain achondrite classes, by "anomalous fading".
NTL
[krad at
Sample Class 250 deg. C]
QUE 93001 MESO 2.2 ± 0.5
QUE 93011 H4 64.2 ± 0.7
QUE 93012 H6 31.2 ± 0.5
ALH 90405 L4 5.5 ± 0.1
EET 90610 L6 8.4 ± 0.1
EET 92051 L6 30 ± 2
EET 92055 L6 50.8 ± 0.7
EET 92059 L6 52.8 ± 0.8
RKP 92407 L6 33.5 ± 0.2
RKP 92408 L6 89 ± 2
ALH 90401 LL6 17.7 ± 0.1
The quoted uncertainties are the standard deviations shown by replicate measurements of 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 group sample descriptions.