Table 1. Apatite fission-track data measured for Hole 976B Alboran Sea samples.
Sample
|
Depth (mbsf)
|
Rock type
|
No. of crystals
|
Dosimeter
|
Spontaneous
|
Induced
|
Age dispersion
|
Central age (Ma)
± 1
|
Mean track length (µm) ± 1 standard error
|
Mean track length standard deviation
|
No. of tracks
|
d
|
Nd
|
s
|
Ns
|
i
|
Ni
|
P2
|
RE%
|
161-976B- |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
77R-2 (Piece 3B) |
685.83 |
Calc-silicate |
(Inadequate apatite separated—no analysis possible.) |
83R-1 (Piece 11A) |
727.66 |
Calc-silicate |
(Apatites full of inclusions—no analysis possible.) |
92R-1 (Piece 10) |
785.26 |
Calc-silicate |
23 |
1.397 |
7745 |
0.203 |
149 |
2.335 |
1712 |
26 |
8.9 |
20.7 ± 1.8 |
14.25 ± 0.15 |
0.83 |
31 |
95R-2 (Piece 1D) |
814.89 |
Gneiss |
22 |
1.397 |
7745 |
0.139 |
104 |
1.540 |
1146 |
85 |
0.5 |
21.5 ± 2.2 |
14.23 ± 0.30 |
1.07 |
14 |
95R-2 (Piece 3) |
815.3 |
Leucosome |
20 |
1.397 |
7745 |
0.146 |
210 |
1.858 |
2670 |
97 |
0 |
18.6 ± 1.4 |
14.54 ± 0.13 |
1.26 |
96 |
96R-1 (Piece 4A) |
823.05 |
Gneiss |
20 |
1.397 |
7745 |
0.156 |
96 |
1.725 |
1064 |
61 |
4.8 |
21.4 ± 2.3 |
14.78 ± 0.21 |
1.01 |
24 |
97R-1 (Piece 7) |
833.05 |
Gneiss |
20 |
1.397 |
7745 |
0.144 |
81 |
1.723 |
972 |
87 |
0 |
19.7 ± 2.3 |
14.31 ± 0.23 |
1.11 |
24 |
97R-2 (Piece 1) |
834.07 |
Schist/gneiss |
20 |
1.397 |
7745 |
0.200 |
111 |
2.704 |
1499 |
27 |
16.5 |
17.8 ± 1.9 |
13.83 ± 0.24 |
1.29 |
29 |
97R-2 (Piece 22) |
835.34 |
Granite |
20 |
1.397 |
7745 |
0.200 |
170 |
2.445 |
2077 |
68 |
0.9 |
19.4 ± 1.6 |
14.30 ± 0.18 |
0.95 |
28 |
98R-1 (Piece 5) |
842.36 |
Migmatite |
20 |
1.397 |
7745 |
0.210 |
152 |
3.276 |
2370 |
95 |
0 |
15.2 ± 1.3 |
14.34 ± 0.20 |
1.11 |
33 |
98R-2 (Piece 2) |
844.23 |
Neosome |
20 |
1.397 |
7745 |
0.182 |
194 |
2.450 |
2611 |
91 |
0 |
17.8 ± 1.3 |
14.65 ± 0.14 |
1.15 |
71 |
102R-2 (Piece 10B) |
882.76 |
Leucosome |
20 |
1.397 |
7745 |
0.186 |
187 |
2.584 |
2593 |
69 |
0.2 |
17.1 ± 1.3 |
14.28 ± 0.11 |
0.91 |
65 |
104R-1 (Piece 10) |
900.69 |
Calc-silicate |
8 |
1.380 |
7252 |
0.168 |
36 |
1.936 |
416 |
96 |
0 |
19.2 ± 3.3 |
No lengths—many inclusions. |
Notes: Basement/sediment interface is 669.73 m below seafloor, d,s, i = track densities (x 106 tr cm-2); Nd,s, i = numbers of tracks counted. Spontaneous and induced: analyses by external detector method using 0.5 for the 4/2 geometry correction factor. P2 is probability of obtaining 2 value for v degrees of freedom, where v = no. crystals - 1. Central age is a modal age, weighted for different precisions of individual crystals (see Galbraith and Laslett, 1993); ages calculated using dosimeter glass CN-5; analyst Carter CN5 =339 calibrated by multiple analyses of IUGS-recommended apatite and zircon age standards (see Hurford, 1990).