Embed Size (px)
Citation preview
RADIOCARBON, Vol 46, Nr 3, 2004, p 1211–1224 © 2004 by the Arizona Board of Regents on behalf of the University of Arizona
1211
RADIOCARBON RESULTS FROM A 13-KYR BP CORAL FROM THE HUON PENINSULA, PAPUA NEW GUINEA
G S Burr1 • Chrystie Galang1 • F W Taylor2 • Christina Gallup3 • R Lawrence Edwards4 • Kirsten Cutler4 • Bill Quirk5
ABSTRACT. This paper presents radiocarbon results from a single Goniastrea favulus coral from Papua New Guinea whichlived continuously between 13.0 and 13.1 kyr BP. The specimen was collected from a drill core on the Huon Peninsula andhas been independently dated with 230Th. A site-specific reservoir correction has been applied to the results, and coral growthbands were used to calibrate individual growth years. Alternating density bands, which are the result of seasonal growth vari-ations, were subsampled to provide 2 integrated 6-month 14C measurements per year. This allows for 20 independent mea-surements to be averaged for each decadal value of the 14C calibration, making these results the highest resolution data setavailable for this brief time range. The finestructure of the data set exhibits 14C oscillations with frequencies on the order of4 to 10 yr, similar to those observed in modern coral 14C records.
INTRODUCTION
Radiocarbon dates may be calibrated using a variety of natural archives. The IntCal98 calibrationcombines tree rings, corals, and marine varved sediments (Stuiver et al. 1998), and the same combi-nation is applied in the present IntCal04 calibration (Reimer et al., this issue). Tree rings provide themost robust results, with potentially annual temporal resolution, but they are limited to trees whichcan be wiggle-matched to known years. Corals, dated with U/Th, were first utilized by Bard et al.(1990, 1993, 1996) to extend the tree-ring limit of the 14C calibration. One potential advantage ofcorals is that the skeletons of some species preserve subannual chemical variations related to seawa-ter chemistry, and have relatively thick and continuous growth bands. Certain of these species canalso live for hundreds of years. These features of coral archives have been widely exploited over thepast 2 decades to produce a wealth of climate data from oxygen isotopic and trace element analyses(Druffel 1997; Gagan et al. 2000). However, there has only been 1 example of a single long-livedcoral applied to the 14C calibration. This is the Diploastrea heliopora analyzed as part of theIntCal98 effort. The Diploastrea was collected from Vanuatu and preserved a 14C record spanningmore than 400 yr during the Younger Dryas (Burr et al. 1998). Two reasons why more corals of thistype are not available are the rare geologic conditions required for their preservation and the logis-tical difficulties which must be overcome to collect them. The Diploastrea sample grew in a tecton-ically active region off the coast of Espiritu Santo Island in Vanuatu. This site is located along a plateboundary that has experienced rapid and variable uplift since the time the coral lived there (Tayloret al. 1987; Cabioch et al. 2003). The amount and direction of tectonic uplift in Vanuatu matched theconcurrent rapid sea-level rise during this period, leaving the coral in a position where it could beretrieved by drilling. As there is no existing technology which can locate large buried coral heads, itwas also fortuitous that the position of the drill rig during the Vanuatu field campaign happened tobe located over this particular coral. Such fortunate circumstances have not often been repeated atother sites and such samples remain rare.
1University of Arizona, NSF-Arizona AMS Laboratory, Tucson, Arizona 85721, USA.2Institute for Geophysics, The University of Texas at Austin, 4412 Spicewood Springs Road, Bld. 600, Austin, Texas 78759-8500, USA.
3University of Minnesota Duluth Geological Sciences, Room 229 HHD175, 10 University Drive, Duluth, Minnesota 55812,USA
4Minnesota Isotope Laboratory, Department of Geology and Geophysics, University of Minnesota, 310 Pillsbury Drive SE,Minneapolis, Minnesota 55455, USA.
5University Medical Center, University of Arizona, Tucson, Arizona 85721, USA.
1212 G S Burr et al.
We report here on another such coral, which lived for about a century between 13.0 and 13.1 kyr BP.This coral is a Goniastrea favulus and was collected during a drilling campaign in 1996. The drillingtook place on an uplifted Holocene terrace located on the Huon Peninsula in Papua New Guinea(Figure 1). The drill was positioned a few meters from the present shoreline, near Kwambu Village,and the sample was encountered at about 40 m depth. The tectonic setting of the Huon Peninsula issimilar to Vanuatu, experiencing continual and rapid uplift throughout the Holocene (Chappell andPolach 1991), and the reef was able to keep up with the approximately 100 m of sea-level rise whichoccurred during the last 13 kyr (Cutler et al. 2003).
METHODS
A 1.5-inch-diameter core was drilled perpendicular to the vertical growth axis of the Goniastreafavulus. This was cut in half lengthwise with a diamond saw and then cut again to into a 5-mm slab.The slab was X-rayed to identify individual growth bands (Figure 2). The X-ray image reveals sub-annual high- and low-density bands. Each pair of high- and low-density bands accounts for 1 yr ofgrowth. An advantage of using this species of coral is that it produces very well-defined densitybands as is evident in Figure 2. Two samples were taken for each year of growth—a low-densitysubsample and a high-density subsample. The sampling was carefully conducted so as to collect theentire light or dark band as viewed in the X-ray image. This was done to obtain an integral 14C mea-surement for the approximately 6-month growth period and thus average higher frequency 14C vari-ations, which are known to occur in corals (Brown et al. 1993; Moore et al. 1997; Guilderson et al.1998).
Each sample was dissolved in acid to produce CO2, and the gas was subsequently reduced to graph-ite for accelerator mass spectrometry (AMS) analysis. All of the samples were subjected to theselective dissolution technique described by Burr et al. (1992). A piece of the core was analyzedusing X-ray powder diffraction to ensure that it was free of secondary calcite. Multiple measure-ments of corals in excess of 100 kyr were used to determine the blank and blank uncertainty. A dis-cussion of the background calculation is given in Donahue et al. (1990).
Figure 1 Location of drill site used to collect the sample
14C Results from a 13-kyr BP Coral from the Huon Peninsula 1213
Figure 2 X-ray image of the Goniastrea favulus sample. Notethe alternating light and dark density bands. The core isapproximately 1.5 inches in diameter.
1214 G S Burr et al.
RESULTS AND DISCUSSION
All of the results presented here are given as fraction modern carbon (F) values, reservoir-correctedfraction modern carbon (FRC) values, and reservoir-corrected 14C ages and 14C values. F is definedby the equation
F = (14C/13C)S / (14C/13C)STD ,
where (14C/13C)S is the sample ratio normalized to δ13C = –25‰ and (14C/13C)STD is the calculatedstandard ratio at 1950, determined from measurements of NBS oxalic acid standards, also normalizedto δ13C = –25‰ (Donahue et al. 1990). Uncorrected F values must be reservoir-corrected with a site-specific reservoir-correction factor to calculate 14C ages that reflect the atmospheric 14C content(equivalent to tree-ring dates). The reservoir-corrected fraction modern carbon FRC is defined here as
FRC ≡ FeRC/τ ,
where RC is the site-specific reservoir correction in years and τ is the Libby mean life (8033 yr). Forthe Huon Peninsula, RC is equal to 407 ± 52 yr (2 σ) (Edwards et al. 1993). This value was chosenbecause these samples came from the same site studied by Edwards et al. (1993). The uncertainty inthe reservoir correction is propagated into the total uncertainty of each measurement (uncorrected Fvalue) to yield the uncertainty in FRC, according to the equation (Burr et al. 1998):
.
The σs represent the uncertainties in FRC, F, and RC.
∆14C values were computed from FRC values using the relation
∆14C = (FRC eλt–1) 1000‰ ,
where t is the age BP of the sample in calendar years.
The total uncertainty in ∆14C is σ∆ and includes errors in FRC and in the 230Th ages (t), according tothe expression
.
Table 1 gives the results of the 230Th measurements. Three independent measurements were madeat the Minnesota Isotope Laboratory and all of them are internally consistent. Table 2 lists the bian-nual 14C results for each growth year and assigns a corresponding calendar age to these, accordingto the 230Th results. These data are summarized as 5-yr weighted averages in Table 3.
Table 1 230Th results.
Sample238U(ppb)
232Th(pg/g)
230Th/238U(activity)
δ234Um(‰)
230Th age BP(kyr) before 1950
δ234Ui(‰)
PNG-96-41.27-88a
aThere are 88 yr of growth preserved. Layer #88 is the uppermost dark/light band couplet.
2166.2 ± 2.9 123.4 ± 5.5 0.12892 ± 0.00037 142.8 ± 1.7 12,985 ± 45 148.2 ± 1.7replicate analysis 12,996 ± 129
PNG-96-41.27-11 1383.5 ± 1.8 9.0 ± 2.4 0.13015 ± 0.00035 143.0 ± 1.6 13,115 ± 43 148.4 ± 1.7
Average date of the core top: 13,011 ± 30 (2 σ)
σFRCe RC( ) τ⁄( )
2σF( )2 F τ⁄( ) e RC( ) τ⁄( )[ ]2
σRC( )2+
12---
=
σ∆ 1000eλt FRCλ( )2σt2 σFRC
2+[ ]
12---
=
14C Results from a 13-kyr BP Coral from the Huon Peninsula 1215
Tabl
e 2
Cal
ibra
ted
14C
resu
lts—
bian
nual
dat
a.La
b #
AA
-Sa
mpl
e ID
δ13C
230 T
h ag
e±2
σF
±1 σ
F RC
±1 σ
14C
age
BP
±2 σ
AA
5272
7PN
G 9
6 41
.27
11D
0.2
13,0
88.5
30.0
0.24
410.
0019
0.25
680.
0022
10,9
2113
5A
A52
728
PNG
96
41.2
7 11
L–0
.813
,088
.030
.00.
2385
0.00
140.
2509
0.00
1711
,107
108
AA
5272
9PN
G 9
6 41
.27
12D
–0.1
13,0
87.5
30.0
0.23
810.
0016
0.25
050.
0019
11,1
2112
0A
A52
730
PNG
96
41.2
7 12
L0.
113
,087
.030
.00.
2352
0.00
130.
2474
0.00
1611
,219
103
AA
5273
1PN
G 9
6 41
.27
13D
–0.1
13,0
86.5
30.0
0.23
800.
0018
0.25
040.
0021
11,1
2413
2A
A52
732
PNG
96
41.2
7 13
L–0
.613
,086
.030
.00.
2403
0.00
190.
2528
0.00
2211
,047
137
AA
5273
3PN
G 9
6 41
.27
14D
0.3
13,0
85.5
30.0
0.23
750.
0023
0.24
980.
0026
11,1
4116
4A
A52
734
PNG
96
41.2
7 14
L–0
.113
,085
.030
.00.
2411
0.00
140.
2536
0.00
1711
,020
107
AA
5273
5PN
G 9
6 41
.27
15D
0.1
13,0
84.5
30.0
0.23
830.
0018
0.25
070.
0021
11,1
1413
2A
A52
736
PNG
96
41.2
7 15
L0.
813
,084
.030
.00.
2415
0.00
250.
2541
0.00
2811
,007
174
AA
5273
7PN
G 9
6 41
.27
16D
–0.2
13,0
83.5
30.0
0.24
010.
0034
0.25
260.
0037
11,0
5423
3A
A52
738
PNG
96
41.2
7 16
L0.
613
,083
.030
.00.
2392
0.00
150.
2516
0.00
1811
,084
113
AA
5273
9PN
G 9
6 41
.27
17D
0.3
13,0
82.5
30.0
0.23
920.
0018
0.25
160.
0021
11,0
8413
2A
A52
740
PNG
96
41.2
7 17
L0.
813
,082
.030
.00.
2385
0.00
150.
2509
0.00
1811
,107
114
AA
5274
1PN
G 9
6 41
.27
18D
0.4
13,0
81.5
30.0
0.23
760.
0017
0.24
990.
0020
11,1
3812
6A
A52
742
PNG
96
41.2
7 18
L1.
313
,081
.030
.00.
2369
0.00
220.
2492
0.00
2511
,161
158
AA
5274
3PN
G 9
6 41
.27
19D
0.5
13,0
80.5
30.0
0.24
650.
0050
0.25
930.
0053
10,8
4233
0A
A52
744
PNG
96
41.2
7 19
L0.
913
,080
.030
.00.
2429
0.00
150.
2555
0.00
1810
,961
112
AA
5274
5PN
G 9
6 41
.27
20D
0.2
13,0
79.5
30.0
0.23
870.
0014
0.25
110.
0017
11,1
0110
8A
A52
746
PNG
96
41.2
7 20
L0.
313
,079
.030
.00.
2451
0.00
160.
2578
0.00
1910
,888
117
AA
5274
7PN
G 9
6 41
.27
21D
0.3
13,0
78.5
30.0
0.24
100.
0014
0.25
350.
0017
11,0
2410
7A
A52
748
PNG
96
41.2
7 21
L0.
313
,078
.030
.00.
2418
0.00
150.
2544
0.00
1810
,997
112
AA
5274
9PN
G 9
6 41
.27
22D
0.1
13,0
77.5
30.0
0.24
020.
0014
0.25
270.
0017
11,0
5010
7A
A52
750
PNG
96
41.2
7 22
L0.
613
077.
030
.00.
2406
0.00
190.
2531
0.00
2211
,037
137
AA
5275
1PN
G 9
6 41
.27
23D
0.4
13,0
76.5
30.0
0.24
020.
0014
0.25
270.
0017
11,0
5010
7A
A52
752
PNG
96
41.2
7 23
L0.
413
,076
.030
.00.
2385
0.00
140.
2509
0.00
1711
,107
108
AA
5275
3PN
G 9
6 41
.27
24D
1.3
13,0
75.5
30.0
0.23
970.
0014
0.25
220.
0017
11,0
6710
7A
A52
754
PNG
96
41.2
7 24
L0.
513
,075
.030
.00.
2447
0.00
140.
2574
0.00
1710
,901
106
AA
5275
5PN
G 9
6 41
.27
25D
0.0
13,0
74.5
30.0
0.24
030.
0014
0.25
280.
0017
11,0
4710
7A
A52
756
PNG
96
41.2
7 25
L–0
.113
,074
.030
.00.
2447
0.00
140.
2574
0.00
1710
,901
106
AA
5275
7PN
G 9
6 41
.27
26D
0.1
13,0
73.5
30.0
0.24
460.
0016
0.25
730.
0019
10,9
0511
7
1216 G S Burr et al.
Tabl
e 2
Cal
ibra
ted
14C
resu
lts—
bian
nual
dat
a. (C
ontin
ued)
Lab
# A
A-
Sam
ple
IDδ13
C23
0 Th
age
±2 σ
F±1
σF R
C±1
σ14
C a
ge B
P±2
σA
A52
758
PNG
96
41.2
7 26
L0.
013
,073
.030
.00.
2415
0.00
140.
2541
0.00
1711
,007
107
AA
5275
9PN
G 9
6 41
.27
27D
0.5
13,0
72.5
30.0
0.24
510.
0017
0.25
780.
0020
10,8
8812
3A
A52
760
PNG
96
41.2
7 27
L0.
013
,072
.030
.00.
2439
0.00
150.
2566
0.00
1810
,928
112
AA
5276
1PN
G 9
6 41
.27
28D
0.0
13,0
71.5
30.0
0.25
390.
0024
0.26
710.
0027
10,6
0516
1A
A52
762
PNG
96
41.2
7 28
L0.
213
,071
.030
.00.
2451
0.00
170.
2578
0.00
2010
,888
123
AA
5276
3PN
G 9
6 41
.27
29D
0.0
13,0
70.5
30.0
0.24
210.
0019
0.25
470.
0022
10,9
8713
6A
A52
764
PNG
96
41.2
7 29
L0.
013
,070
.030
.00.
2374
0.00
160.
2497
0.00
1911
,145
120
AA
5276
5PN
G 9
6 41
.27
30D
0.5
13,0
69.5
30.0
0.23
740.
0015
0.24
970.
0018
11,1
4511
4A
A52
766
PNG
96
41.2
7 30
L0.
613
,069
.030
.00.
2387
0.00
140.
2511
0.00
1711
,101
108
AA
5276
7PN
G 9
6 41
.27
31D
0.6
13,0
68.5
30.0
0.24
240.
0014
0.25
500.
0017
10,9
7710
6A
A52
768
PNG
96
41.2
7 31
L0.
113
,068
.030
.00.
2383
0.00
140.
2507
0.00
1711
,114
108
AA
5276
9PN
G 9
6 41
.27
32D
0.2
13,0
67.5
30.0
0.24
440.
0028
0.25
710.
0031
10,9
1119
1A
A52
770
PNG
96
41.2
7 32
L–0
.313
,067
.030
.00.
2361
0.00
140.
2484
0.00
1711
,189
109
AA
5277
1PN
G 9
6 41
.27
33D
–0.2
13,0
66.5
30.0
0.23
840.
0014
0.25
080.
0017
11,1
1110
8A
A52
772
PNG
96
41.2
7 33
L–0
.313
,066
.030
.00.
2336
0.00
150.
2457
0.00
1811
,274
116
AA
5277
3PN
G 9
6 41
.27
34D
0.0
13,0
65.5
30.0
0.23
500.
0014
0.24
720.
0017
11,2
2610
9A
A52
774
PNG
96
41.2
7 34
L–0
.213
,065
.030
.00.
2385
0.00
140.
2509
0.00
1711
,107
108
AA
5277
5PN
G 9
6 41
.27
35D
0.3
13,0
64.5
30.0
0.24
000.
0017
0.25
250.
0020
11,0
5712
5A
A52
776
PNG
96
41.2
7 35
L0.
013
,064
.030
.00.
2382
0.00
170.
2506
0.00
2011
,118
126
AA
5277
7PN
G 9
6 41
.27
36D
0.5
13,0
63.5
30.0
0.23
790.
0017
0.25
030.
0020
11,1
2812
6A
A52
778
PNG
96
41.2
7 36
L0.
213
,063
.030
.00.
2363
0.00
170.
2486
0.00
2011
,182
127
AA
5277
9PN
G 9
6 41
.27
37D
0.3
13,0
62.5
30.0
0.23
660.
0014
0.24
890.
0017
11,1
7210
8A
A52
780
PNG
96
41.2
7 37
L–0
.213
,062
.030
.00.
2410
0.00
140.
2535
0.00
1711
,024
107
AA
5278
1PN
G 9
6 41
.27
38D
0.0
13,0
61.5
30.0
0.23
730.
0014
0.24
960.
0017
11,1
4810
8A
A52
782
PNG
96
41.2
7 38
L0.
213
,061
.030
.00.
2391
0.00
180.
2515
0.00
2111
,087
132
AA
5278
3PN
G 9
6 41
.27
39D
0.0
13,0
60.5
30.0
0.23
780.
0015
0.25
020.
0018
11,1
3111
4A
A52
784
PNG
96
41.2
7 39
L–0
.113
,060
.030
.00.
2370
0.00
140.
2493
0.00
1711
,158
108
AA
5278
5PN
G 9
6 41
.27
40D
0.1
13,0
59.5
30.0
0.24
200.
0015
0.25
460.
0018
10,9
9011
2A
A52
786
PNG
96
41.2
7 40
L–0
.313
,059
.030
.00.
2373
0.00
220.
2496
0.00
2511
,148
158
AA
5278
7PN
G 9
6 41
.27
41D
0.3
13,0
58.5
30.0
0.23
650.
0016
0.24
880.
0019
11,1
7512
0A
A52
788
PNG
96
41.2
7 41
L–0
.213
,058
.030
.00.
2383
0.00
140.
2507
0.00
1711
,114
108
14C Results from a 13-kyr BP Coral from the Huon Peninsula 1217
Tabl
e 2
Cal
ibra
ted
14C
resu
lts—
bian
nual
dat
a. (C
ontin
ued)
Lab
# A
A-
Sam
ple
IDδ13
C23
0 Th
age
±2 σ
F±1
σF R
C±1
σ14
C a
ge B
P±2
σA
A52
789
PNG
96
41.2
7 42
D0.
613
,057
.530
.00.
2514
0.00
210.
2645
0.00
2410
,684
144
AA
5279
0PN
G 9
6 41
.27
42L
–0.1
13,0
57.0
30.0
0.24
170.
0016
0.25
430.
0019
11,0
0011
8A
A52
791
PNG
96
41.2
7 43
D–0
.313
,056
.530
.00.
2372
0.00
370.
2495
0.00
4011
,151
256
AA
5279
2PN
G 9
6 41
.27
43L
–0.1
13,0
56.0
30.0
0.23
870.
0024
0.25
110.
0027
11,1
0117
0A
A52
793
PNG
96
41.2
7 44
D0.
413
,055
.530
.00.
2385
0.00
160.
2509
0.00
1911
,107
120
AA
5279
4PN
G 9
6 41
.27
44L
–0.2
13,0
55.0
30.0
0.23
870.
0023
0.25
110.
0026
11,1
0116
3A
A52
795
PNG
96
41.2
7 45
D0.
213
,054
.530
.00.
2411
0.00
180.
2536
0.00
2111
,020
131
AA
5279
6PN
G 9
6 41
.27
45L
0.2
13,0
54.0
30.0
0.23
810.
0019
0.25
050.
0022
11,1
2113
8A
A52
797
PNG
96
41.2
7 46
D–0
.313
,053
.530
.00.
2415
0.00
160.
2541
0.00
1911
,007
118
AA
5279
8PN
G 9
6 41
.27
46L
0.0
13,0
53.0
30.0
0.24
160.
0015
0.25
420.
0018
11,0
0411
2A
A52
799
PNG
96
41.2
7 47
D0.
613
,052
.530
.00.
2420
0.00
180.
2546
0.00
2110
,990
130
AA
5280
0PN
G 9
6 41
.27
47L
0.3
13,0
52.0
30.0
0.23
910.
0016
0.25
150.
0019
11,0
8711
9A
A52
801
PNG
96
41.2
7 48
D0.
113
,051
.530
.00.
2393
0.00
290.
2517
0.00
3211
,080
202
AA
5280
2PN
G 9
6 41
.27
48L
0.6
13,0
51.0
30.0
0.23
790.
0013
0.25
030.
0016
11,1
2810
2A
A52
803
PNG
96
41.2
7 49
D0.
113
,050
.530
.00.
2388
0.00
180.
2512
0.00
2111
,097
132
AA
5280
4PN
G 9
6 41
.27
49L
0.3
13,0
50.0
30.0
0.23
730.
0020
0.24
960.
0023
11,1
4814
5A
A52
805
PNG
96
41.2
7 50
D–0
.113
,049
.530
.00.
2379
0.00
150.
2503
0.00
1811
,128
114
AA
5280
6PN
G 9
6 41
.27
50L
0.0
13,0
49.0
30.0
0.24
250.
0046
0.25
510.
0049
10,9
7430
9A
A52
807
PNG
96
41.2
7 51
D–0
.513
,048
.530
.00.
2386
0.00
230.
2510
0.00
2611
,104
163
AA
5280
8PN
G 9
6 41
.27
51L
0.0
13,0
48.0
30.0
0.23
850.
0016
0.25
090.
0019
11,1
0712
0A
A52
809
PNG
96
41.2
7 52
D0.
413
,047
.530
.00.
2374
0.00
150.
2497
0.00
1811
,145
114
AA
5281
0PN
G 9
6 41
.27
52L
0.1
13,0
47.0
30.0
0.23
790.
0015
0.25
030.
0018
11,1
2811
4A
A52
811
PNG
96
41.2
7 53
D0.
313
,046
.530
.00.
2393
0.00
170.
2517
0.00
2011
,080
125
AA
5281
2PN
G 9
6 41
.27
53L
0.4
13,0
46.0
30.0
0.23
930.
0018
0.25
170.
0021
11,0
8013
2A
A52
813
PNG
96
41.2
7 54
D–0
.113
,045
.530
.00.
2389
0.00
150.
2513
0.00
1811
,094
113
AA
5281
4PN
G 9
6 41
.27
54L
0.5
13,0
45.0
30.0
0.23
730.
0017
0.24
960.
0020
11,1
4812
6A
A52
815
PNG
96
41.2
7 55
D0.
013
,044
.530
.00.
2371
0.00
130.
2494
0.00
1611
,155
102
AA
5281
6PN
G 9
6 41
.27
55L
0.4
13,0
44.0
30.0
0.23
910.
0017
0.25
150.
0020
11,0
8712
6A
A52
817
PNG
96
41.2
7 56
D0.
013
,043
.530
.00.
2439
0.00
300.
2566
0.00
3310
,928
204
AA
5281
8PN
G 9
6 41
.27
57L
–0.1
13,0
43.0
30.0
0.24
870.
0017
0.26
160.
0020
10,7
7112
2A
A52
819
PNG
96
41.2
7 57
D–0
.113
,042
.530
.00.
2381
0.00
180.
2505
0.00
2111
,121
132
1218 G S Burr et al.
Tabl
e 2
Cal
ibra
ted
14C
resu
lts—
bian
nual
dat
a. (C
ontin
ued)
Lab
# A
A-
Sam
ple
IDδ13
C23
0 Th
age
±2 σ
F±1
σF R
C±1
σ14
C a
ge B
P±2
σA
A52
820
PNG
96
41.2
7 57
L0.
413
,042
.030
.00.
2396
0.00
210.
2521
0.00
2411
,070
150
AA
5282
1PN
G 9
6 41
.27
58D
–0.5
13,0
41.5
30.0
0.23
940.
0020
0.25
180.
0023
11,0
7714
4A
A52
822
PNG
96
41.2
7 58
L0.
013
,041
.030
.00.
2386
0.00
160.
2510
0.00
1911
,104
120
AA
5282
3PN
G 9
6 41
.27
59D
–0.5
13,0
40.5
30.0
0.23
780.
0017
0.25
020.
0020
11,1
3112
6A
A52
824
PNG
96
41.2
7 59
L–0
.113
,040
.030
.00.
2385
0.00
170.
2509
0.00
2011
,107
126
AA
5282
5PN
G 9
6 41
.27
60D
–0.4
13,0
39.5
30.0
0.24
150.
0018
0.25
410.
0021
11,0
0713
1A
A52
826
PNG
96
41.2
7 60
L–0
.313
,039
.030
.00.
2389
0.00
210.
2513
0.00
2411
,094
150
AA
5282
7PN
G 9
6 41
.27
61D
–0.8
13,0
38.5
30.0
0.24
060.
0016
0.25
310.
0019
11,0
3711
9A
A52
828
PNG
96
41.2
7 61
L–0
.313
,038
.030
.00.
2351
0.00
150.
2473
0.00
1811
,223
115
AA
5282
9PN
G 9
6 41
.27
62D
–0.7
13,0
37.5
30.0
0.24
150.
0015
0.25
410.
0018
11,0
0711
3A
A52
830
PNG
96
41.2
7 62
L–0
.213
,037
.030
.00.
2375
0.00
170.
2498
0.00
2011
,141
126
AA
5283
1PN
G 9
6 41
.27
63D
–0.7
13,0
36.5
30.0
0.23
950.
0014
0.25
190.
0017
11,0
7410
7A
A52
832
PNG
96
41.2
7 63
L–0
.513
,036
.030
.00.
2372
0.00
310.
2495
0.00
3411
,151
216
AA
5283
3PN
G 9
6 41
.27
64D
–0.7
13,0
35.5
30.0
0.23
900.
0014
0.25
140.
0017
11,0
9110
8A
A52
834
PNG
96
41.2
7 64
L–0
.913
,035
.030
.00.
2406
0.00
290.
2531
0.00
3211
,037
201
AA
5283
5PN
G 9
6 41
.27
65D
–0.8
13,0
34.5
30.0
0.23
780.
0015
0.25
020.
0018
11,1
3111
4A
A52
836
PNG
96
41.2
7 65
L–0
.113
,034
.030
.00.
2435
0.00
250.
2562
0.00
2810
,941
173
AA
5283
7PN
G 9
6 41
.27
66D
–1.0
13,0
33.5
30.0
0.24
730.
0014
0.26
020.
0017
10,8
1610
5A
A52
838
PNG
96
41.2
7 66
L1.
313
,033
.030
.00.
2428
0.00
190.
2554
0.00
2210
,964
136
AA
5283
9PN
G 9
6 41
.27
67D
–1.0
13,0
32.5
30.0
0.25
350.
0023
0.26
670.
0026
10,6
1715
5A
A52
840
PNG
96
41.2
7 67
L–0
.113
,032
.030
.00.
2374
0.00
330.
2497
0.00
3611
,145
229
AA
5284
1PN
G 9
6 41
.27
68D
–0.4
13,0
31.5
30.0
0.24
490.
0018
0.25
760.
0021
10,8
9512
9A
A52
842
PNG
96
41.2
7 68
L0.
313
,031
.030
.00.
2421
0.00
210.
2547
0.00
2410
,987
149
AA
5284
3PN
G 9
6 41
.27
69D
0.5
13,0
30.5
30.0
0.24
030.
0017
0.25
280.
0020
11,0
4712
5A
A52
844
PNG
96
41.2
7 69
L0.
613
,030
.030
.00.
2404
0.00
150.
2529
0.00
1811
,044
113
AA
5284
5PN
G 9
6 41
.27
70D
1.0
13,0
29.5
30.0
0.24
180.
0019
0.25
440.
0022
10,9
9713
7A
A52
846
PNG
96
41.2
7 70
L0.
113
,029
.030
.00.
2399
0.00
140.
2524
0.00
1711
,060
107
AA
5284
7PN
G 9
6 41
.27
71D
–0.3
13,0
28.5
30.0
0.24
710.
0020
0.25
990.
0023
10,8
2314
0A
A52
848
PNG
96
41.2
7 71
L0.
113
,028
.030
.00.
2401
0.00
170.
2526
0.00
2011
,054
125
AA
5284
9PN
G 9
6 41
.27
72D
–0.9
13,0
27.5
30.0
0.23
940.
0016
0.25
180.
0019
11,0
7711
9A
A52
850
PNG
96
41.2
7 72
L0.
013
,027
.030
.00.
2391
0.00
160.
2515
0.00
1911
,087
119
AA
5285
1PN
G 9
6 41
.27
73D
–0.7
13,0
26.5
30.0
0.24
180.
0019
0.25
440.
0022
10,9
9713
7
14C Results from a 13-kyr BP Coral from the Huon Peninsula 1219
Tabl
e 2
Cal
ibra
ted
14C
resu
lts—
bian
nual
dat
a. (C
ontin
ued)
Lab
# A
A-
Sam
ple
IDδ13
C23
0 Th
age
±2 σ
F±1
σF R
C±1
σ14
C a
ge B
P±2
σA
A52
852
PNG
96
41.2
7 73
L–0
.513
,026
.030
.00.
2457
0.00
350.
2585
0.00
3810
,868
235
AA
5285
3PN
G 9
6 41
.27
74D
–0.4
13,0
25.5
30.0
0.25
090.
0027
0.26
390.
0030
10,7
0018
1A
A52
854
PNG
96
41.2
7 74
L–0
.513
,025
.030
.00.
2405
0.00
190.
2530
0.00
2211
,040
137
AA
5285
5PN
G 9
6 41
.27
75D
–1.2
13,0
24.5
30.0
0.24
030.
0016
0.25
280.
0019
11,0
4711
9A
A52
856
PNG
96
41.2
7 75
L–1
.413
,024
.030
.00.
2392
0.00
240.
2516
0.00
2711
,084
169
AA
5285
7PN
G 9
6 41
.27
76D
–0.6
13,0
23.5
30.0
0.24
010.
0014
0.25
260.
0017
11,0
5410
7A
A52
858
PNG
96
41.2
7 76
L–0
.113
,023
.030
.00.
2399
0.00
160.
2524
0.00
1911
,060
119
AA
5285
9PN
G 9
6 41
.27
77D
0.0
13,0
22.5
30.0
0.24
600.
0014
0.25
880.
0017
10,8
5910
5A
A52
860
PNG
96
41.2
7 77
L–0
.113
,022
.030
.00.
2392
0.00
260.
2516
0.00
2911
,084
182
AA
5286
1PN
G 9
6 41
.27
78D
–0.6
13,0
21.5
30.0
0.24
100.
0011
0.25
350.
0014
11,0
2490
AA
5286
2PN
G 9
6 41
.27
78L
–0.5
13,0
21.0
30.0
0.23
990.
0016
0.25
240.
0019
11,0
6011
9A
A52
863
PNG
96
41.2
7 79
D–0
.813
,020
.530
.00.
2411
0.00
130.
2536
0.00
1611
,020
101
AA
5286
4PN
G 9
6 41
.27
79L
0.0
13,0
20.0
30.0
0.24
380.
0013
0.25
650.
0016
10,9
3110
0A
A52
865
PNG
96
41.2
7 80
D–0
.913
,019
.530
.00.
2414
0.00
160.
2539
0.00
1911
,010
119
AA
5286
6PN
G 9
6 41
.27
80L
–0.3
13,0
19.0
30.0
0.24
060.
0018
0.25
310.
0021
11,0
3713
1A
A52
867
PNG
96
41.2
7 81
D–0
.113
,018
.530
.00.
2431
0.00
160.
2557
0.00
1910
,954
118
AA
5286
8PN
G 9
6 41
.27
81L
–0.9
13,0
18.0
30.0
0.24
360.
0034
0.25
630.
0037
10,9
3723
0A
A52
869
PNG
96
41.2
7 82
D–0
.413
,017
.530
.00.
2469
0.00
500.
2597
0.00
5310
,829
329
AA
5287
0PN
G 9
6 41
.27
82L
0.5
13,0
17.0
30.0
0.24
410.
0017
0.25
680.
0020
10,9
2112
3A
A52
871
PNG
96
41.2
7 83
D0.
013
,016
.530
.00.
2518
0.00
570.
2649
0.00
6110
,671
367
AA
5287
2PN
G 9
6 41
.27
83L
0.1
13,0
16.0
30.0
0.24
820.
0051
0.26
110.
0054
10,7
8733
4A
A52
873
PNG
96
41.2
7 84
D–0
.513
,015
.530
.00.
2515
0.00
350.
2646
0.00
3810
,681
230
AA
5287
4PN
G 9
6 41
.27
84L
–0.3
13,0
15.0
30.0
0.23
970.
0028
0.25
220.
0031
11,0
6719
5A
A52
875
PNG
96
41.2
7 85
D0.
013
,014
.530
.00.
2486
0.00
140.
2615
0.00
1710
,774
104
AA
5287
6PN
G 9
6 41
.27
85L
–1.5
13,0
14.0
30.0
0.23
990.
0021
0.25
240.
0024
11,0
6015
0A
A52
877
PNG
96
41.2
7 86
D–2
.013
,013
.530
.00.
2403
0.00
210.
2528
0.00
2411
,047
150
AA
5287
8PN
G 9
6 41
.27
86L
–2.1
13,0
13.0
30.0
0.24
220.
0030
0.25
480.
0033
10,9
8420
6A
A52
879
PNG
96
41.2
7 87
D–2
.013
,012
.530
.00.
2316
0.00
230.
2436
0.00
2511
,343
168
AA
5288
0PN
G 9
6 41
.27
87L
–1.9
13,0
12.0
30.0
0.24
230.
0029
0.25
490.
0032
10,9
8019
9A
A52
881
PNG
96
41.2
7 88
D–1
.513
,011
.530
.00.
2348
0.00
190.
2470
0.00
2211
,233
140
AA
5288
2PN
G 9
6 41
.27
88L
–1.0
13,0
11.0
30.0
0.24
070.
0019
0.25
320.
0022
11,0
3413
7
1220 G S Burr et al.
Figure 3 shows the 5-yr weighted averages of the 14C dates versus 230Th ages. The trend of the datais rather flat, with some intra-decadal variability. Weighted average )14C values are plotted againstthe 230Th ages in Figure 4. This data also show intra-decadal variability with a small peak in ∆14C atabout 13,075 BP. The gross trend in ∆14C shows a modest increase with increasing age over theentire period.
Table 3 5-yr weighted average values: FRC, 14C age BP, and ∆14C.a230Th age BP ±2 σ FRC ±2 σ nb 14C age BP ±2 σ ∆14C (‰) ±2 σ13,015 30 0.2541 0.0018 10 11,031 121 222.9 21.213,020 30 0.2525 0.0018 10 10,955 82 235.2 9.713,025 30 0.2537 0.0014 10 11,009 44 227.8 6.813,030 30 0.2548 0.0028 10 11,005 76 229.0 10.613,035 30 0.2504 0.0020 10 10,958 82 237.0 14.513,040 30 0.2507 0.0014 10 11,085 51 218.4 6.813,045 30 0.2524 0.0026 10 11,069 76 221.5 11.613,050 30 0.2520 0.0014 10 11,114 38 215.5 5.813,055 30 0.2506 0.0012 10 11,066 45 223.5 5.813,060 30 0.2529 0.0024 10 11,066 83 224.2 12.613,065 30 0.2514 0.0016 10 11,117 45 217.2 5.813,070 30 0.2557 0.0026 10 11,130 64 216.0 8.813,075 30 0.2540 0.0024 10 10,949 88 244.4 11.713,080 30 0.2541 0.0014 10 11,024 44 233.5 6.813,085 30 0.2576 0.0026 10 11,075 57 226.5 6.813,090 30 0.2505 0.0038 6 11,094 58 224.3 9.7
aWeighted averages were computed with the formulae of Bevington and Robinson (1992).bn is the number of individual samples used to compute the weighted average.
Figure 3 14C age versus 230Th age: 5-yr averaged data
14C Results from a 13-kyr BP Coral from the Huon Peninsula 1221
Figure 5 shows a comparison of the results of this study with the earlier Diploastrea results. The 14Cage data and ∆14C values from both corals follow a single trend. Note that the site-specific reservoircorrections for these 2 sites are different by about 90 yr.
An interesting feature of these results is the finestructure which can be seen in Figure 6. Here, weplot a 5-point smoothed curve for all of the data. The smoothed curve shown in the figure showsvariability in ∆14C with a frequency on the order of 4 to 10 yr and variable amplitudes of up to 40‰.These variations are similar to those observed in modern corals whose 14C content has been shownto be related to El Niño-induced fluctuations (Brown et al. 1993; Guilderson and Schrag 1998).Such effects are also known to produce oxygen isotopic variations and these have been describedfrom modern corals in Papua New Guinea (Tudhope et al. 2001). The oxygen isotope record of theGoniastrea favulus sample studied here, and the potential for paleo-El Niño events, is the subject ofa parallel study to be discussed elsewhere.
CONCLUSIONS
This study highlights the advantages of analyzing consecutive subannual growth layers of a singlecoral, which allows annual variations in ∆14C to be identified for the better part of a century. Intra-decadal ∆14C variations between 13.0 and 13.1 kyr BP show variations which are similar to thoseobserved in living corals. The time resolution of the sampling provides for the most precise 14Cresults available for this period and the internal consistency of the results supports the quoted preci-sion for the measurements. Using individual growth bands, 5-yr average values for the 14C calibra-tion have been computed here using 10 independent measurements, and the external variance of thispopulation of points determines the precision of the calibrated age. Coral samples of the type exam-ined here are difficult to sample in practice, but their usefulness for calibration purposes warrantsfurther efforts to collect them.
Figure 4 ∆14C versus 230Th age: 5-yr averaged data
1222 G S Burr et al.
Figure 5 Comparison of Vanuatu and PNG results: (a) 14C age versus 230Th age; (b) ∆14C versus 230Th age. Diploastrea(Vanuatu) are 10-yr averages and Goniastrea (Papua New Guinea) are 5-yr averages.
a
b
14C Results from a 13-kyr BP Coral from the Huon Peninsula 1223
ACKNOWLEDGMENTS
We acknowledge the support for this project from the National Science Foundation (EAR9730699and EAR0115488). We are very grateful for the enthusiastic support of the local inhabitants ofKwambu Village and of the support of the Sialum District government. We would like to thankDamien Kelleher and Eugene Wallensky of the Australian National University for their drillingexpertise. We are also indebted to Dr John Chappell for making available the drilling equipment.
REFERENCES
Figure 6 Finestructure in the Goniastrea favulus record: 5-point FFT smoothed curve
Bard E, Hamelin B, Fairbanks RG, Zindler A. 1990. Cal-ibration of the 14C time scale over the past 30,000years using mass spectrometric U-Th ages from Bar-bados corals. Nature 345:405–10.
Bard E, Arnold M, Fairbanks RG, Hamelin B. 1993.230Th-234U and 14C ages obtained by mass spectrome-try on corals. Radiocarbon 35(1):191–9.
Bard E, Hamelin B, Arnold M, Montaggioni L, CabiochG, Faure G, Rougerie F. 1996. Deglacial sea-levelrecord from Tahiti corals and the timing of globalmeltwater discharge. Nature 382:241–4
Bevington PR, Robinson DK. 1992. Data Reduction andError Analysis for the Physical Sciences. New York:McGraw-Hill, Inc. 328 p.
Brown TA, Farwell GW, Grootes PM, Schmidt FH,Stuiver M. 1993. Intra-annual variability of the radio-carbon content of corals from the Galapagos Islands.Radiocarbon 35(2):245–51.
Burr GS, Edwards RL, Donahue DJ, Druffel ERM, Tay-lor FW. 1992. Mass spectrometric 14C and U-Th mea-surements in coral. Radiocarbon 34(3):611–8.
Burr GS, Beck JW, Taylor FW, Récy J, Edwards RL, Ca-bioch G, Corrège T, Donahue DJ, O’Malley JM. 1998.A high-resolution radiocarbon calibration between11,700 and 12,400 calendar years BP derived from230Th ages of corals from Espiritu Santo Island, Van-uatu. Radiocarbon 40(3):1093–105.
Cabioch G, Banks-Cutler K, Beck JW, Burr GS, Corrège
1224 G S Burr et al.
T, Edwards RL, Taylor FW. 2003. Continuous reefgrowth during the last 23 cal kyr BP in a tectonicallyactive zone (Vanuatu, southwest Pacific). QuaternaryScience Reviews 22:1771–86.
Chappell J, Polach H. 1991. Post-glacial sea-level risefrom a coral record at Huon Peninsula, Papua NewGuinea. Nature 349:147–9.
Cutler KA, Edwards RL, Taylor FW, Cheng H, Adkins J,Gallup CD, Cutler PM, Burr GS, Bloom AL. 2003.Rapid sea-level fall and deep-ocean temperaturechange since the last interglacial period. Earth andPlanetary Science Letters 206:253–71.
Donahue DJ, Linick TW, Jull AJT. 1990. Isotope-ratioand background corrections for accelerator mass spec-trometry radiocarbon measurements. Radiocarbon32(2):135–42.
Druffel ERM. 1997. Geochemistry of corals: proxies ofpast ocean chemistry, ocean circulation, and climate.Proceedings National Academy of Sciences 94:8354–61.
Edwards RL, Beck JW, Burr GS, Donahue DJ, ChappellJMA, Bloom AL, Druffel ERM, Taylor FW. 1993. Alarge drop in atmospheric 14C/12C and reduced meltingin the Younger Dryas, documented with 230Th ages ofcorals. Science 260:962–8.
Gagan MK, Ayliffe LK, Beck JW, Cole JE, Druffel ERM,Dunbar RB, Schrag DP. 2000. New views of tropicalpaleoclimates from corals. Quaternary Science Re-views 19:45–64.
Guilderson TP, Schrag DP, Kashgarian M, Southon J.1998. Radiocarbon variability in the western equato-rial Pacific inferred from a high-resolution coralrecord from Nauru Island. Journal of Geophysical Re-
search-Oceans 103(C11):24,641–50.Guilderson TP, Schrag DP. 1998. Abrupt shift in subsur-
face temperatures in the tropical Pacific associatedwith changes in El Niño. Science 281:240–3.
Moore MD, Schrag DP, Kashgarian M. 1997. Coral ra-diocarbon constraints on the source of the Indonesianthroughflow. Journal of Geophysical Research102(C6):12,359–65.
Reimer PJ, Baillie MGL, Bard E, Bayliss A, Beck JW,Blackwell PG, Buck CE, Burr GS, Cutler KB, DamonPE, Edwards RL, Fairbanks RG, Friedrich M, Guilder-son TP, Herring C, Hughen KA, Kromer B, McCor-mac G, Manning S, Bronk Ramsey C, Reimer RW,Remmele S, Southon JR, Stuiver M, Talamo S, TaylorFW, van der Plicht J, Weyhenmeyer CE. 2004.IntCal04 terrestrial radiocarbon age calibration, 0–26cal kyr BP. Radiocarbon, this issue.
Stuiver M, Reimer PJ, Bard E, Beck JW, Burr GS,Hughen KA, Kromer B, McCormac G, van der PlichtJ, Spurk M. 1998. IntCal98 radiocarbon age calibra-tion, 24,000–0 cal BP. Radiocarbon 40(3):1041–83.
Taylor FW, Frohlich C, Lecolle J, Strecker M. 1987.Analysis of partially emerged corals and reef terracesin the central Vanuatu arc: comparison of contempo-rary coseismic and nonseismic with Quaternary verti-cal movements. Journal of Geophysical Research 92:4905–33.
Tudhope AW, Chilcott CP, McCulloch MT, Cook ER,Chappell J, Ellam RM, Lea DW, Lough JM,Shimmield GB. 2001. Variability in the El Niño-Southern Oscillation through a glacial-interglacial cy-cle. Science 291:1511–7.
![F RADIOCARBON, UNIVERSITY OF TEXAS RADIOCARBON DATES II · F RADIOCARBON, Vor,. 6, 1964, P. 138-159] UNIVERSITY OF TEXAS RADIOCARBON DATES II M. A. TAMERS, F. J. PEARSON, JR., and](https://img.dokumen.tips/doc/110x75/606d59c493119417f12a3a02/f-radiocarbon-university-of-texas-radiocarbon-dates-ii-f-radiocarbon-vor-6.jpg)