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Table T10. Effect of correction for initial 230Th for crustal contamination and (the worst case) seawater Th incorporation, Expedition 325. (See table notes.)
Core, section,
interval (cm)
|
Dated
lithology
|
232Th
(ppb)
|
2σ
|
U-Th age no
correction
|
U-Th age crustal
correction
|
U-Th age seawater
correction
|
|
k.y. BP
|
2σ
|
k.y. BP
|
2σ
|
k.y. BP
|
2σ
|
|
325-
|
|
M0031A-16R-1, 0–3
|
C
|
0.20
|
0.00
|
25.13
|
0.24
|
25.1
|
0.2
|
25.1
|
0.2
|
|
M0032A-8R-3, 0–2
|
C
|
13.56
|
0.23
|
20.42
|
0.24
|
19.7
|
0.8
|
15.9
|
4.6
|
|
M0032A-18R-2, 8–10
|
C
|
0.99
|
0.02
|
61.10
|
0.80
|
61.1
|
0.8
|
61.0
|
0.8
|
|
M0033A-15R-2, 5–7
|
C
|
110.40
|
1.90
|
31.07
|
0.32
|
27.2
|
4.0
|
4.9
|
30.6
|
|
M0034A-13R-2, 6–8
|
C
|
0.17
|
0.00
|
11.18
|
0.11
|
11.2
|
0.1
|
11.2
|
0.1
|
|
M0035A-20R-2, 0–2
|
C
|
0.30
|
0.01
|
21.33
|
0.20
|
21.3
|
0.2
|
21.3
|
0.2
|
|
M0036A-18R-2, 8–10
|
C
|
10.39
|
0.17
|
20.82
|
0.19
|
20.7
|
0.2
|
20.1
|
0.8
|
|
M0037A-7R-2, 2–4
|
C
|
7.44
|
0.13
|
12.54
|
0.11
|
12.3
|
0.2
|
11.3
|
1.3
|
|
M0039A-16R-2, 8–10
|
C
|
7.22
|
0.12
|
18.82
|
0.15
|
18.7
|
0.2
|
18.3
|
0.6
|
|
M0040A-8R-2, 5–8
|
C
|
7.45
|
0.13
|
24.73
|
0.22
|
24.6
|
0.2
|
24.1
|
0.6
|
|
M0042A-24R-2, 8–9
|
C
|
2.87
|
0.05
|
169.30
|
4.50
|
169.2
|
4.4
|
168.7
|
4.4
|
|
M0043A-18R-2, 2–4
|
C
|
2.81
|
0.05
|
20.28
|
0.20
|
20.3
|
0.2
|
20.1
|
0.3
|
|
M0046A-11R-1, 10–11
|
C
|
1.55
|
0.03
|
17.19
|
0.16
|
17.2
|
0.2
|
17.1
|
0.2
|
|
M0047A-11R-2, 5–6
|
C
|
0.96
|
0.02
|
20.78
|
0.19
|
20.8
|
0.2
|
20.7
|
0.2
|
|
M0049B-9R-2, 4–5
|
C
|
6.83
|
0.12
|
15.80
|
0.15
|
15.7
|
0.2
|
15.2
|
0.6
|
|
M0053A-25R-2, 2–3
|
C
|
6.68
|
0.12
|
23.65
|
0.24
|
23.6
|
0.3
|
23.2
|
0.5
|
|
M0054B-4R-2, 2–3
|
C
|
2.71
|
0.05
|
20.08
|
0.18
|
20.1
|
0.2
|
19.9
|
0.3
|
|
M0055A-5R-3, 0–1
|
C
|
12.80
|
0.22
|
25.05
|
0.25
|
24.8
|
0.3
|
23.7
|
1.4
|
|
M0056A-13-2, 2–3
|
C/b
|
26.90
|
0.50
|
84.10
|
1.10
|
83.3
|
1.3
|
79.3
|
5.0
|
|
M0057A-15R-3, 9–10
|
C
|
1.95
|
0.04
|
No closed system age possible
|
Notes: U-Th age interpretations are assumed to be a closed system. Three assumptions for the correction of initial 230Th were made. First, no correction was made (this is the value, rounded to 1 ka, used for the purposes of preliminary dating). Second, two further age interpretations involving corrections for initial 230Th were made, one assuming a detrital Th contamination from continental material ([230Th/232Th] = 1.030) and another assuming Th contamination scavenged from seawater ([230Th/232Th] = 9.250). BP = age before present (1950 AD). C = coral, b = bivalve.
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