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Earth, Planets and Space

Table 2 Summary of zircon (U–Th)/He parameters

From: First report of (U–Th)/He thermochronometric data across Northeast Japan Arc: implications for the long-term inelastic deformation

Sample

Lab. no

He no.

No. of grains analyzed

[4He]

(ncc)

Mass

(mg)

aMean F T

[U]

(ppm)

[Th]

(ppm)

Th/U

b[eU]

(ppm)

Corrected age ± 1σ

(Ma)

Grain length

(μm)

Grain radius

(μm)

cGrain morphology

A02-ST04

11241

34006

1

21.124

0.0146

0.83

308.4

122.0

0.40

337.1

35.1 ± 2.2

305.5

60.1

2T

A02-ST04

11242

34009

1

36.171

0.0218

0.84

297.6

103.1

0.35

321.8

42.3 ± 2.6

411.9

60.1

2T

A02-ST04

11243

34012

1

38.534

0.0298

0.87

250.4

108.9

0.43

276.0

38.3 ± 2.4

349.9

84.0

2T

A02-ST04

11244

34037

1

22.589

0.0116

0.82

316.3

133.6

0.42

347.7

46.0 ± 2.9

270.1

57.8

2T

         

Weighted mean age ± 95% CI

39.6 ± 7.4

   

A02-ST05

11237

33994

1

8.232

0.0186

0.83

130.4

43.9

0.34

140.7

25.8 ± 1.6

371.3

59.2

2T

A02-ST05

11238

33997

1

10.409

0.0220

0.85

357.4

111.8

0.31

383.6

10.1 ± 0.6

363.2

66.7

2T

A02-ST05

11239

34000

1

2.846

0.0089

0.80

273.6

117.8

0.43

301.3

8.7 ± 0.5

254.2

51.9

2T

A02-ST05

11240

34003

1

5.915

0.0093

0.79

306.1

80.7

0.26

325.1

16.1 ± 1.0

294.5

47.0

2T

         

Weighted mean age ± 95% CI

N/A

   

A02-ST06

11233

33982

1

35.540

0.0146

0.83

839.8

278.8

0.33

905.3

22.1 ± 1.4

295.4

61.8

2T

A02-ST06

11234

33985

1

55.748

0.0269

0.86

386.1

144.4

0.37

420.0

40.4 ± 2.5

388.6

71.3

2T

A02-ST06

11235

33988

1

19.360

0.0154

0.83

303.2

115.9

0.38

330.5

31.2 ± 1.9

299.0

63.3

2T

A02-ST06

11236

33991

1

20.796

0.0106

0.81

504.5

160.2

0.32

542.2

29.8 ± 1.8

273.3

54.0

2T

         

Weighted mean age ± 95% CI

N/A

   

A02-ST07

11230

33918

1

5.562

0.0080

0.79

209.3

102.9

0.49

233.5

24.5 ± 1.5

238.6

51.1

2T

A02-ST07

11231

33976

1

11.496

0.0086

0.78

348.2

140.3

0.40

381.1

28.9 ± 1.8

320.1

42.2

2T

A02-ST07

11232

33979

1

12.184

0.0068

0.79

471.6

192.5

0.41

516.8

28.3 ± 1.8

216.1

50.9

2T

A02-ST07

11313

34052

1

26.722

0.0122

0.82

596.6

179.3

0.30

638.7

28.1 ± 1.7

278.0

58.3

2T

         

Weighted mean age ± 95% CI

27.2 ± 3.3

   

A02-ST08

11225

33903

1

48.968

0.0105

0.81

550.4

233.9

0.42

605.3

62.8 ± 3.9

260.9

56.3

2T

A02-ST08

11226

33906

1

37.863

0.0184

0.85

241.6

89.8

0.37

262.7

64.2 ± 4.0

289.0

73.7

2T

A02-ST08

11227

33909

1

29.750

0.0128

0.83

394.8

162.7

0.41

433.0

43.8 ± 2.7

265.5

63.0

2T

A02-ST08

11228

33912

1

34.455

0.0164

0.82

305.3

123.6

0.40

334.3

51.6 ± 3.2

373.3

54.7

2T

         

Weighted mean age ± 95% CI

N/A

   

A02-ST09

11221

33891

1

9.199

0.0099

0.80

686.1

307.7

0.45

758.5

10.0 ± 0.6

290.2

49.5

2T

A02-ST09

11222

33894

1

11.643

0.0125

0.82

529.5

132.4

0.25

560.6

13.7 ± 0.8

315.7

53.1

2T

A02-ST09

11224

33900

1

12.592

0.0095

0.79

889.9

310.4

0.35

962.8

11.3 ± 0.7

310.5

45.8

2T

A02-ST09

11314

34055

1

4.012

0.0116

0.82

252.1

110.7

0.44

278.1

10.2 ± 0.6

268.9

58.3

2T

         

Weighted mean age ± 95% CI

11.0 ± 2.4

   

A02-ST13

11217

33879

1

33.892

0.0081

0.80

501.6

170.2

0.34

541.6

63.3 ± 3.9

245.9

50.2

2T

A02-ST13

11218

33882

1

25.187

0.0078

0.80

2016.2

518.8

0.26

2138.1

12.4 ± 0.8

239.2

50.2

2T

A02-ST13

11219

33885

1

24.142

0.0174

0.84

1203.4

255.7

0.21

1263.4

9.0 ± 0.6

306.1

67.1

2T

A02-ST13

11220

33888

1

27.567

0.0105

0.81

901.6

203.8

0.23

949.5

22.6 ± 1.4

267.2

55.0

2T

         

Weighted mean age ± 95% CI

N/A

   

A02-ST15

11213

33870

1

31.938

0.0095

0.81

697.5

281.3

0.40

763.6

36.2 ± 2.2

252.3

54.2

2T

A02-ST15

11214

33873

1

58.324

0.0058

0.77

2506.9

893.1

0.36

2716.8

30.2 ± 1.9

222.5

44.6

2T

A02-ST15

11215

33876

1

53.732

0.0109

0.81

1253.7

471.0

0.38

1364.4

29.7 ± 1.8

298.2

51.2

2T

A02-ST15

11216

33940

1

74.872

0.0070

0.79

2883.1

791.4

0.27

3069.1

28.8 ± 1.8

239.2

46.8

2T

         

Weighted mean age ± 95% CI

30.7 ± 4.8

   

Fish Canyon Tuff standard

FCT

11088

33750

1

7.695

0.0062

0.77

317.8

155.8

0.49

354.4

28.6 ± 1.8

236.2

44.1

2T

FCT

11089

33753

1

9.671

0.0056

0.77

462.1

288.8

0.62

530.0

26.8 ± 1.7

214.6

44.8

2T

FCT

11090

33846

1

12.907

0.0112

0.81

286.7

145.9

0.51

321.0

29.5 ± 1.8

299.2

51.8

2T

FCT

11093

33855

1

10.809

0.0068

0.77

369.0

253.7

0.69

428.6

30.4 ± 1.9

271.2

41.7

2T

FCT

11094

33858

1

9.219

0.0091

0.80

271.6

152.1

0.56

307.3

27.1 ± 1.7

254.5

52.3

2T

         

Weighted mean age ± 95% CI

28.4 ± 1.5

   
         

dReference age ± 1σ:

28.01 ± 0.04

   
  1. The weighted mean ages and the errors were obtained using Isoplot ver. 4.15 (Ludwig 2012). For samples exhibiting a negative correlation between eU and grain ages, weighted mean ages were not calculated and are reported as “N/A”
  2. a F T is α-ejection correction after Farley et al. (1996)
  3. bEffective uranium concentration, weights U and Th for their alpha productivity, computed as [U] + 0.235[Th] (Shuster et al. 2006)
  4. cCrystal morphology: 2T = idiomorphic whole grain (Brown et al. 2013)
  5. dThe reference age of Fish Canyon Tuff (FCT) is from Phillips and Matchan (2013)
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