|
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
[krad at 250° C]
|
| |
|
GRA 98006
|
EUC
|
7.1 ± 0.4
|
|
GRA 98019
|
EUC
|
5.6 ± 0.5
|
|
GRA 98037
|
EUC
|
6 ± 2
|
|
GRA 98042
|
EUC
|
5.6 ± 0.5
|
|
GRA 98043
|
EUC
|
3.0 ± 0.7
|
|
GRA 98054
|
EUC
|
4.8 ± 0.6
|
|
GRA 98055
|
EUC
|
6.9 ± 0.6
|
|
|
|
|
|
GRA 98032
|
URE
|
n.d.*
|
|
|
|
|
|
GRA 98023
|
H3
|
62 ± 4
|
|
GRA 98050
|
H3
|
40 ± 4
|
|
|
|
|
|
GRA 98013
|
H4
|
82.1 ± 0.3
|
|
GRA 98031
|
H4
|
50 ± 1
|
|
|
|
|
|
GRA 98002
|
H5
|
140 ± 2
|
|
GRA 98004
|
H5
|
16.4 ± 0.2
|
|
GRA 98007
|
H5
|
55 ± 3
|
|
GRA 98008
|
H5
|
7.3 ± 0.1
|
|
GRA 98009
|
H5
|
55.9 ± 0.3
|
|
GRA 98010
|
H5
|
92.9 ± 0.6
|
|
GRA 98012
|
H5
|
1.4 ± 0.1
|
|
GRA 98014
|
H5
|
176.1 ± 0.3
|
|
GRA 98015
|
H5
|
40.7 ± 0.1
|
|
GRA 98016
|
H5
|
37.0 ± 0.3
|
|
GRA 98017
|
H5
|
139.8 ± 0.3
|
|
GRA 98040
|
H5
|
14 ± 2
|
|
GRA 98047
|
H5
|
63.2 ± 0.2
|
|
GRA 98051
|
H5
|
47.6 ± 0.3
|
|
|
|
|
|
GRA 98034
|
H6
|
32.0 ± 0.6
|
|
GRA 98048
|
H6
|
34.3 ± 0.5
|
|
|
|
|
|
GRA 98003
|
L5
|
23.8 ± 0.1
|
|
GRA 98011
|
L5
|
60.9 ± 0.1
|
|
GRA 98020
|
L5
|
48.5 ± 0.1
|
|
GRA 98035
|
L5
|
103 ± 6
|
|
|
|
|
|
GRA 98036
|
L6
|
1.0 ± 0.1
|
|
GRA 98041
|
L6
|
19 ± 5
|
|
GRA 98046
|
L6
|
36.6 ± 0.2
|
|
GRA 98049
|
L6
|
9.5 ± 0.1
|
|
QUE 97555
|
L6
|
3.8 ± 0.1
|
|
|
|
|
|
QUE 97431
|
LL5
|
0.8 ± 0.3
|
|
QUE 97433
|
LL5
|
12 ± 2
|
|
QUE 97441
|
LL5
|
2.3 ± 0.5
|
|
QUE 97490
|
LL5
|
4.4 ± 0.2
|
|
QUE 97524
|
LL5
|
5.7 ± 0.1
|
|
QUE 97525
|
LL5
|
3.2 ± 0.4
|
|
QUE 97575
|
LL5
|
56.6 ± 0.1
|
|
QUE 97612
|
LL5
|
8.2 ± 0.3
|
*n.d. = natural and induced
thermoluminescence below detection limits.
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.
Induced TL sensitivity data and the shape of the induced
TL glow curve suggest that GRA98023 and GRA98050 are subtype 3.6 and 3.7,
respectively.
GRA 98041 (L6) has very low TL sensitivity and may be highly shocked.
Pairings confirmed by TL data:
- H3: GRA 98050 possibly with GRA 98023.
- EUC: GRA 98019, GRA 98037, GRA
98042, GRA 98043, GRA 98054, and GRA 98055 with GRA 98006 (AMN 23:1).
Pairing not confirmed by TL Data
- L6: GRA 98049 with GRA 98046 (AMN 23:1).
Pairings suggested by TL data:
- H4: GRA 98031 with GRA 95215 (AMN 21:1).
- H5: GRA 98016 with GRA 95202 (AMN 20:2).
- H5: GRA 98009, GRA 98015, and GRA 98051 with GRA 98007.
- H5: GRA 98014 and GRA98017 with GRA 98002 and possibly with GRA 95201 (AMN 20:2).
- H6: GRA 98048 with GRA 98034.
- L5: GRA 98020 with GRA 95203 (AMN 20:2)
- L6: QUE 97555 with QUE 94623 (AMN 20:1).
- LL5: QUE 97431 with QUE 97395 (AMN 23:1)
- LL5: QUE 97441, QUE 97490, QUE 97524 and QUE 97525 with the QUE 97016 group (AMN 22:2).
- LL5: QUE 97443 with QUE 97403 (AMN 23:1).
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