Auxiliary Material for
Westerly jet–East Asian summer monsoon connection during the Holocene
by Kana Nagashima, Ryuji Tada, and Shin Toyoda
Supplementary Methods
Analysis of quartz content
To normalize the intensity of the E1′ center, the quartz content was estimated by the
internal standard method [Klug and Alexander, 1974] using the XRD of PANalytical
X’part Pro at the University of Tokyo. The scanning region was 20° – 30° 2θ, scanned at
1.1° 2θ/second with a sampling step of 0.017° 2θ. Silicon powder (Wako Pure Chemical
Industries, Ltd.) was used as the internal standard because its principal diffraction peak
(28.4° 2θ) does not overlap with the peaks of other minerals. We added a known amount
of silicon powder to the sample and measured the height of the second highest quartz
peak at 20.9° 2θ (the main quartz peak at 26.6° 2θ overlaps that of illite at 26.7° 2θ).
Measurements were conducted in triplicate, and the results were averaged. The quartz
content (%) is calculated as:
Qtz content = 100 × (Wsi/Wsample) × (IQtz/ISi)/C
(S1)
where Wsi and Wsample are the weights of the silicon standard and the sample,
respectively, IQtz/ISi is the height ratio of the quartz diffraction peak at 20.9° 2θ to the
1
silicon diffraction peak at 28.4° 2θ, and C is a constant that corrects for the effect of
quartz crystallinity on the peak height. The crystallinity of quartz, and its analysis, is
detailed below. To estimate the C dependence on quartz crystallinity, we chose six
quartz samples of different crystallinity index (CI; CI = 3.0, 5.6, 7.8, 8.6, 9.1, and 10).
From the relationship between the ratios Wsi/Wsample and IQtz/ISi, we then determined C
for these six samples and constructed a CI vs. C calibration curve (C = 0.00077 × CI2 +
0.096), from which the C of each measured sample was estimated from its CI value.
Analysis of quartz crystallinity
We defined the CI of quartz as the degree of resolution of the d(212) reflection of quartz
at 1.382 Å on an XRD diffractogram (Fig. S1) according to the following equation
[Murata and Norman, 1976]:
CI = 10aF/b,
(S2)
where a is the height of the d(212) peak at 67.7° 2θ with respect to the trough between
the peaks at 67.7° 2θ and 67.9° 2θ, b is the height of the peak at 67.7° 2θ with respect to
the background (Fig. S1), and F is a scaling factor. In this method, a/b is first multiplied
by 10 to convert fractions into numbers that are typically greater than 1.0 and then
multiplied by a value of F which is selected such that the CI of automorphic quartz is 10.
In the present study, the scaling factor was set to 1.246 on the basis of the XRD results
for an industrial standard quartz sample (20–28 mesh granular quartz, Wako Pure
2
Chemical Industries, Ltd.).
For the measurement of CI, approximately 80 mg of each silt fraction sample was
powdered in an agate mortar. Then, the CI of the powdered samples was measured with
the XRD of PANalytical X’Pert PRO at the University of Tokyo by scanning from 66° to
70° 2θ, with a scanning speed of 0.023° 2θ/s and a sampling step of 0.0042° 2θ.
Figure S1. Example X-ray powder diffractogram of the d(212) peak of quartz.
Quantities a and b were measured to obtain the crystallinity indices of the samples.
3
Figure S2. An age–depth curve for core D-GC-6 [modified after Yokoyama et al., 2007]
(upper) and a diagram illustrating the changes in linear sedimentation rate with age
(lower). Filled squires indicate the radiocarbon dates used as principle control points
[Yokoyama et al., 2007]. The age model is consistent (within error) with the five
bioevents determined from radiolarian assemblage changes [Itaki and Ikehara, 2003;
Itaki et al., unpublished data], the ages of which were determined using AMS 14C dates
of sediment cores derived from shallower sites within the Japan Sea (see Fig. S3).
4
Figure S3. Correlation of five radiolarian events among cores D-GC-6, GH98-1232,
C-GC-8, and GH872-308 [Itaki et al., unpublished data]. Location of each core is
shown in the map on the left.
5
Table S1. ESR signal intensities and crystallinity indices of quartz in the fine silt
fraction samples from core D-GC-6.
Depth, cm
Age, kyr BP
ESR Intensity (Spin Unit)
CI
0.6
0.02
9.4
8.6
1.9
0.07
8.8
8.4
3.1
0.12
10.4
8.2
4.4
0.17
11.1
8.5
5.6
0.22
10.0
8.4
6.9
0.26
11.7
8.4
8.1
0.31
13.0
8.6
10.6
0.41
10.8
8.5
11.9
0.45
11.0
8.6
13.1
0.50
12.0
8.5
14.4
0.55
10.0
8.5
15.6
0.60
10.2
8.5
16.9
0.65
11.4
8.5
18.1
0.69
10.0
8.5
19.4
0.74
12.0
8.3
21.9
0.87
11.2
8.4
23.1
0.95
10.7
8.5
24.4
1.04
11.7
8.6
25.6
1.12
10.5
8.5
26.9
1.20
10.1
8.5
28.1
1.28
10.8
8.6
29.4
1.37
9.0
8.6
30.6
1.45
11.4
8.5
31.9
1.53
9.8
8.4
33.1
1.61
9.2
8.5
34.4
1.70
11.0
8.4
35.6
1.78
8.8
8.4
36.9
1.86
8.3
8.3
38.1
1.94
10.1
8.3
40.1
2.07
10.1
8.4
41.3
2.15
9.0
8.5
43.8
2.32
10.2
8.6
45.1
2.40
8.8
8.4
46.4
2.49
8.5
8.5
49.1
2.66
9.7
8.4
50.3
2.75
10.5
8.4
51.6
2.83
9.7
8.4
6
52.8
2.91
9.1
8.4
54.1
2.99
9.2
8.4
55.3
3.07
9.8
8.4
56.6
3.16
9.7
8.4
57.8
3.24
10.5
8.6
59.1
3.32
9.0
8.4
60.3
3.40
13.0
8.5
62.8
3.57
10.1
8.0
64.1
3.65
12.2
8.6
65.3
3.73
10.1
8.4
66.6
3.81
9.3
8.3
67.8
3.90
12.9
8.5
69.1
3.98
12.7
8.4
70.3
4.06
11.6
8.4
71.6
4.14
12.5
8.6
71.6
4.14
11.1
8.3
72.8
4.23
13.2
8.2
74.1
4.31
10.2
8.3
77.8
4.56
13.7
8.3
79.1
4.64
12.1
8.3
80.3
4.72
9.1
8.3
81.6
4.80
8.5
8.2
82.8
4.88
11.4
8.5
84.1
4.97
12.0
8.3
85.3
5.05
11.0
8.2
86.6
5.13
13.0
8.6
87.8
5.21
9.1
8.2
89.1
5.30
10.7
8.4
91.6
5.46
10.3
8.4
94.1
5.63
8.9
8.3
95.3
5.71
9.8
8.4
96.6
5.79
8.7
8.2
97.8
5.87
8.6
8.4
99.1
5.95
10.8
8.2
100.3
6.04
10.6
8.5
101.6
6.12
10.9
8.6
102.8
6.20
9.7
8.2
104.1
6.28
11.1
8.6
105.3
6.37
10.9
8.4
106.6
6.45
9.9
8.2
110.3
6.69
10.8
8.5
111.6
6.78
9.9
8.4
7
112.8
6.86
11.1
8.3
115.3
7.02
11.9
8.5
116.6
7.11
9.9
8.6
119.1
7.33
11.1
8.5
120.3
7.47
11.7
8.4
129.1
8.50
10.8
8.4
130.3
8.64
12.1
8.5
131.6
8.79
13.2
8.7
134.1
9.08
11.2
8.4
135.3
9.23
10.8
8.6
136.6
9.37
12.2
8.4
137.8
9.52
11.5
8.3
139.1
9.67
13.1
8.0
140.3
9.81
11.3
8.3
141.6
9.96
10.9
8.4
142.8
10.11
10.6
8.3
145.3
10.40
10.6
8.0
146.3
10.52
11.5
8.5
147.6
10.66
10.9
8.2
148.8
10.81
11.2
8.1
150.1
10.95
10.9
8.3
152.6
11.26
11.3
8.3
153.8
11.42
10.4
8.4
155.1
11.58
12.3
8.5
156.3
11.74
12.2
8.3
157.6
11.90
12.1
8.4
8
References
Itaki, T., and K. Ikehara (2003), Radiolarian biozonation for the upper Quaternary in the
Japan Sea, J. Geol. Soc. Jpn., 109, 96–105.
Klug, H. P., and L. E. Alexander (1974), X-Ray Diffraction Procedure, 2nd ed., 966 pp.,
John Wiley, Hoboken, N. J.
Murata, K., and Norman, M., 1976, An index of crystallinity for quartz, Am. J. Sci., 276,
1120–1130.
Yokoyama, Y., Y. Kido, R. Tada, I. Minami, R. C. Finkel, and M. Matsuzaki (2007),
Japan Sea oxygen isotope stratigraphy and global sea-level changes for the last
50,000
years
recorded
in
sediment
cores
Palaeogeogra. Palaeoclimatol. Palaeoecol., 247, 5–17.
9
from
the
Oki
ridge,