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Table 3 Ion microprobe Th-U–Pb analyses of fissure monazite

From: Ion microprobe dating of fissure monazite in the Western Alps: insights from the Argentera Massif and the Piemontais and Briançonnais Zones

Groups

Analysis ID

U (μg/g)

Th (μg/g)

Th/U

208Pb/204Pb

1σ (%)

207Pb/206Pb

1σ (%)

208Pb/232Th

1σ (%)

f208 from 207(%)

204—corr

204—corr spot ages

207—corr

207—corr spot ages

208Pb/232Th

1σ (%)

208Pb/232Th Age (Ma)

1σ (abs.)

208Pb/232Th

1σ (%)

208Pb/232Th Age (Ma)

1σ (abs.)

High-pressure regions

A

VIU1@01

390

42,000

108

2739

8

0.078

2.0

0.001576

1.5

0.3

0.001554

1.5

31.38

0.47

0.001571

1.5

31.73

0.49

VIU1@02

330

31,000

94

3335

10

0.071

2.3

0.001518

1.5

0.3

0.001501

1.5

30.31

0.46

0.001514

1.5

30.58

0.47

VIU1@03

230

26,000

113

3274

11

0.087

2.5

0.001537

1.5

0.4

0.001519

1.5

30.69

0.47

0.001531

1.5

30.92

0.47

VIU1@04

330

36,000

109

2810

9

0.082

2.1

0.001611

1.5

0.4

0.001589

1.5

32.09

0.49

0.001605

1.5

32.42

0.50

VIU1@06

250

28,000

112

2499

11

0.100

2.4

0.001655

1.5

0.6

0.001630

1.5

32.91

0.50

0.001645

1.5

33.21

0.51

VIU1@11

240

22,000

92

2261

11

0.120

2.1

0.001622

1.5

0.9

0.001594

1.5

32.20

0.49

0.001607

1.5

32.46

0.50

B

VIU1@05

280

19,000

68

1588

10

0.128

2.1

0.001485

1.5

1.2

0.001449

1.5

29.27

0.44

0.001468

1.5

29.64

0.45

VIU1@07

310

17,000

55

2116

14

0.093

2.5

0.001457

1.5

0.9

0.001431

1.5

28.91

0.44

0.001444

1.5

29.16

0.45

VIU1@08

320

21,000

66

2545

14

0.094

2.5

0.001483

1.5

0.8

0.001460

1.5

29.50

0.45

0.001471

1.5

29.72

0.46

VIU1@09

310

17,000

55

2893

16

0.085

2.6

0.001508

1.5

0.8

0.001488

1.5

30.04

0.46

0.001496

1.5

30.21

0.47

VIU1@10

280

13,000

46

1791

14

0.093

2.4

0.001563

1.7

1.2

0.001529

1.7

30.88

0.52

0.001544

1.7

31.18

0.53

VIU1@12

240

22,000

91

1686

9

0.184

1.8

0.001548

1.6

1.6

0.001513

1.5

30.55

0.47

0.001523

1.6

30.76

0.48

VIU1@13

270

14,000

52

2582

14

0.110

2.4

0.001493

1.5

1.1

0.001471

1.5

29.71

0.45

0.001477

1.5

29.83

0.46

VIU1@14

250

12,000

48

1564

13

0.121

2.4

0.001550

1.5

1.4

0.001511

1.5

30.53

0.47

0.001527

1.5

30.85

0.48

VIU1@15

290

14,000

48

1547

13

0.133

2.4

0.001434

1.6

1.5

0.001398

1.6

28.24

0.45

0.001412

1.6

28.52

0.46

VIU1@16

250

20,000

80

2316

11

0.104

2.2

0.001571

1.5

0.8

0.001546

1.5

31.22

0.47

0.001558

1.5

31.47

0.48

VIU1@17

270

21,000

78

2263

11

0.103

2.3

0.001501

1.6

0.7

0.001475

1.5

29.79

0.46

0.001489

1.6

30.08

0.47

VIU1@18

260

21,000

81

2431

11

0.088

2.5

0.001524

1.5

0.5

0.001500

1.5

30.29

0.46

0.001516

1.5

30.61

0.47

VIU1@19

290

18,000

62

3043

14

0.091

2.6

0.001452

1.5

0.6

0.001434

1.5

28.96

0.44

0.001443

1.5

29.14

0.45

VIU1@20

360

17,000

47

2522

13

0.086

2.6

0.001432

1.6

0.7

0.001412

1.5

28.52

0.44

0.001423

1.6

28.74

0.45

 

BALZI2@34

410

2700

7

1299

95

0.141

11.7

0.002080

1.2

4.4

0.002018

3.1

40.74

1.25

0.001988

1.4

40.14

0.57

 

BALZI2@36

210

3800

18

938

95

0.374

13.2

0.002306

1.6

7.4

0.002396

5.8

48.38

2.79

0.002135

1.9

43.10

0.81

 

BALZI2@37

760

4600

6

/

0

0.068

24.4

0.002502

1.1

0.8

0.002502

/

50.50

/

0.002483

1.2

50.12

0.58

 

BALZI2@39

950

7000

7

1341

95

0.119

16.1

0.002273

2.1

2.1

0.002207

3.4

44.56

1.51

0.002225

2.1

44.92

0.95

 

BALZI2@40

510

5500

11

744

42

0.174

7.0

0.002073

2.3

4.7

0.001966

3.1

39.69

1.22

0.001975

2.3

39.88

0.91

A

BALZI2@32

150

3900

26

594

47

0.340

8.7

0.001922

1.3

6.5

0.001797

3.3

36.29

1.21

0.001796

1.5

36.28

0.53

BALZI2@33

250

3900

16

/

0

0.074

14.2

0.001774

2.2

0.9

0.001774

/

35.81

/

0.001757

2.2

35.48

0.77

BALZI2@42

320

3800

12

306

25

0.263

4.6

0.001997

2.5

11.0

0.001745

3.8

35.23

1.33

0.001778

2.6

35.90

0.92

BALZI2@43

240

4900

20

218

25

0.479

5.1

0.002144

1.1

16.0

0.001764

4.4

35.62

1.58

0.001800

1.3

36.36

0.49

BALZI2@44

320

5800

18

2020

67

0.089

11.6

0.001749

2.2

1.0

0.001716

2.5

34.65

0.86

0.001731

2.2

34.96

0.76

 

BALZI2@31

86

4100

48

704

55

0.336

11.0

0.001741

1.0

4.6

0.001646

3.2

33.24

1.05

0.001661

1.1

33.55

0.37

B

BALZI2@26

110

6800

62

5432

95

0.061

16.1

0.001472

1.6

0.2

0.001461

1.8

29.51

0.52

0.001468

1.6

29.65

0.48

BALZI2@27

88

6500

74

/

0

0.165

10.7

0.001500

1.8

1.3

0.001500

/

30.29

/

0.001480

1.8

29.90

0.54

BALZI2@28

63

5800

92

109

11

0.715

2.7

0.002091

1.1

28.7

0.001347

4.1

27.22

1.11

0.001492

1.4

30.13

0.41

BALZI2@29

20

2100

104

1859

95

0.235

15.0

0.001517

1.4

2.4

0.001485

2.4

30.00

0.72

0.001481

1.4

29.91

0.43

BALZI2@30

14

1700

120

/

0

0.150

27.7

0.001558

1.1

1.0

0.001558

/

31.47

/

0.001542

1.1

31.15

0.35

BALZI2@46

41

5900

142

3122

67

0.069

14.8

0.001471

1.5

0.3

0.001453

1.7

29.34

0.50

0.001467

1.5

29.63

0.44

BALZI2@47

35

3200

90

685

47

0.121

20.0

0.001480

1.2

0.6

0.001396

2.9

28.21

0.82

0.001471

1.2

29.71

0.37

BALZI2@48

67

3600

54

/

0

0.163

19.1

0.001561

1.0

1.1

0.001621

2.2

32.74

0.70

0.001545

1.1

31.20

0.34

BALZI2@49

71

3800

54

/

0

0.117

16.5

0.001495

1.6

1.2

0.001495

/

30.20

/

0.001478

1.6

29.85

0.47

BALZI2@50

98

5500

56

/

0

0.106

17.3

0.001553

1.5

0.9

0.001553

/

31.37

/

0.001539

1.5

31.09

0.46

 

BALZI2@01

96

7100

74

175

8

0.529

1.7

0.001551

3.1

20.3

0.001209

3.0

24.43

0.74

0.001237

3.2

24.99

0.79

 

BALZI2@02

82

5500

67

151

10

0.519

2.6

0.001445

3.2

16.7

0.001076

3.6

21.73

0.78

0.001203

3.3

24.29

0.79

 

BALZI2@12

130

8600

66

437

16

0.459

3.2

0.001440

2.9

9.0

0.001313

3.0

26.52

0.80

0.001310

2.9

26.47

0.77

 

BALZI2@24

25

2500

100

139

20

0.678

4.8

0.001788

1.1

21.9

0.001290

5.7

26.05

1.48

0.001396

1.5

28.20

0.44

 

BALZI2@25

86

5600

65

/

0

0.077

16.8

0.001349

1.1

0.4

0.001349

/

27.24

/

0.001343

1.1

27.13

0.31

C

BALZI2@13

67

4100

61

103

8

0.651

1.9

0.001915

3.1

32.7

0.001196

3.7

24.16

0.89

0.001288

3.1

26.02

0.82

BALZI2@15

82

3500

43

152

16

0.578

3.0

0.001710

2.6

28.2

0.001275

4.4

25.75

1.13

0.001228

2.8

24.81

0.68

BALZI2@16

130

3600

28

151

16

0.459

3.3

0.001576

2.6

22.4

0.001173

4.5

23.70

1.06

0.001224

2.8

24.73

0.68

BALZI2@17

140

3800

27

273

20

0.421

3.5

0.001506

2.6

16.4

0.001293

3.6

26.11

0.93

0.001259

2.7

25.43

0.68

BALZI2@19

85

3100

36

175

12

0.380

2.8

0.001464

3.3

15.2

0.001152

3.8

23.26

0.88

0.001241

3.3

25.07

0.83

BALZI2@21

200

3500

18

237

20

0.361

3.9

0.001501

2.7

15.5

0.001257

4.0

25.38

1.01

0.001268

2.7

25.62

0.70

BALZI2@22

250

4200

17

197

19

0.391

3.8

0.001567

2.7

16.8

0.001283

4.3

25.92

1.12

0.001304

2.8

26.34

0.74

 

BALZI2@14

45

3100

68

98

14

0.573

3.2

0.001555

2.7

31.2

0.000944

5.6

19.07

1.07

0.001070

2.9

21.61

0.63

 

BALZI2@23

210

3200

15

86

11

0.628

2.2

0.002683

2.6

45.8

0.001504

5.1

30.37

1.54

0.001455

3.1

29.39

0.90

D

BALZI2@20

170

3500

21

83

17

0.279

4.8

0.000688

2.6

20.4

0.000368

8.2

7.43

0.61

0.000548

2.8

11.08

0.31

BALZI2@51

42

2800

67

62

18

0.678

4.1

0.001293

3.2

57.2

0.000542

11.8

10.96

1.29

0.000553

5.6

11.18

0.63

Argentera Massif

A

MORI1@06

9

4800

551

712

19

0.473

5.3

0.000786

2.0

2.6

0.000743

2.2

15.02

0.32

0.000766

2.0

15.47

0.31

MORI1@07

9

3500

369

555

19

0.476

5.5

0.000805

2.3

3.3

0.000749

2.6

15.13

0.39

0.000779

2.3

15.73

0.37

MORI1@08

10

2400

238

426

21

0.391

5.8

0.000803

2.1

4.2

0.000737

2.7

14.90

0.40

0.000770

2.1

15.55

0.33

MORI1@09

4

3000

742

792

26

0.446

5.5

0.000820

2.6

4.3

0.000786

2.8

15.88

0.44

0.000785

2.6

15.86

0.41

MORI1@10

6

3700

598

609

22

0.503

4.9

0.000795

2.1

4.8

0.000744

2.4

15.04

0.36

0.000756

2.1

15.28

0.32

MORI1@11

10

3500

345

450

19

0.449

5.4

0.000803

2.1

3.9

0.000734

2.5

14.82

0.37

0.000772

2.1

15.59

0.33

MORI1@12

10

5000

500

541

18

0.446

5.3

0.000786

2.2

3.0

0.000730

2.4

14.74

0.36

0.000762

2.2

15.40

0.34

MORI1@13

10

4600

484

1097

27

0.366

6.2

0.000782

2.0

2.4

0.000754

2.2

15.23

0.33

0.000763

2.0

15.41

0.31

MORI1@14

8

3400

422

866

22

0.364

5.7

0.000731

2.2

2.3

0.000698

2.3

14.10

0.33

0.000714

2.2

14.43

0.32

MORI1@15

14

3400

252

440

19

0.532

4.7

0.000805

2.1

6.1

0.000734

2.6

14.83

0.38

0.000756

2.1

15.27

0.33

MORI1@16

13

2800

212

443

21

0.425

5.4

0.000780

2.2

4.9

0.000712

2.7

14.40

0.39

0.000742

2.2

14.99

0.33

MORI1@17

14

2700

195

591

25

0.451

5.4

0.000785

2.2

5.4

0.000734

2.7

14.83

0.40

0.000742

2.3

15.00

0.34

MORI1@18

14

2400

167

609

15

0.270

5.5

0.000715

1.9

1.5

0.000672

2.1

13.58

0.28

0.000704

1.9

14.23

0.28

B

MORI1@01

54

2500

47

434

21

0.211

4.2

0.000810

2.1

5.9

0.000738

2.7

14.91

0.40

0.000762

2.2

15.39

0.33

MORI1@02

51

3300

65

637

21

0.205

4.4

0.000772

2.0

3.7

0.000726

2.3

14.66

0.33

0.000744

2.0

15.03

0.30

MORI1@03

38

3700

97

453

17

0.202

4.5

0.000737

2.3

3.1

0.000674

2.5

13.62

0.34

0.000714

2.3

14.42

0.33

MORI1@04

51

4400

86

555

17

0.222

4.2

0.000777

2.1

3.1

0.000723

2.3

14.61

0.33

0.000753

2.1

15.21

0.32

MORI1@05

49

4400

90

843

20

0.188

4.6

0.000767

2.0

2.3

0.000735

2.1

14.85

0.32

0.000749

2.0

15.14

0.30

MORI1@20

55

1900

35

586

15

0.134

3.7

0.000799

2.1

2.5

0.000746

2.2

15.07

0.33

0.000779

2.1

15.74

0.33

MORI1@21

55

1600

29

548

16

0.186

3.4

0.000804

2.1

4.0

0.000747

2.3

15.10

0.34

0.000772

2.1

15.59

0.33

MORI1@22

71

1700

24

840

21

0.164

3.8

0.000777

2.0

3.5

0.000742

2.1

14.98

0.31

0.000750

2.0

15.15

0.30

MORI1@23

54

1200

22

463

18

0.160

4.0

0.000734

2.0

4.0

0.000672

2.4

13.59

0.32

0.000704

2.0

14.22

0.29

A

VINA1@17

32

29,000

904

1855

11

0.240

4.4

0.000821

1.5

0.4

0.000804

1.5

16.25

0.25

0.000818

1.5

16.53

0.25

VINA1@20

15

12,000

777

564

10

0.685

2.5

0.000837

1.5

5.1

0.000780

1.6

15.76

0.25

0.000795

1.5

16.06

0.25

VINA1@22

29

20,000

699

667

8

0.615

2.0

0.000861

1.5

4.0

0.000811

1.5

16.39

0.25

0.000826

1.5

16.70

0.26

VINA1@23

21

11,000

528

685

14

0.556

3.8

0.000817

1.7

2.9

0.000771

1.7

15.58

0.27

0.000793

1.7

16.02

0.27

VINA1@24

28

20,000

706

1423

13

0.251

5.2

0.000822

1.6

0.5

0.000800

1.6

16.16

0.26

0.000818

1.6

16.52

0.27

VINA1@25

34

20,000

595

2366

17

0.240

5.1

0.000819

1.6

0.5

0.000806

1.6

16.28

0.25

0.000815

1.6

16.46

0.26

VINA1@26

35

23,000

665

307

5

0.676

1.5

0.000871

1.6

7.4

0.000761

1.6

15.38

0.24

0.000807

1.6

16.30

0.26

 

VINA1@18

31

37,000

1185

1499

9

0.359

3.6

0.000743

1.5

0.5

0.000724

1.5

14.62

0.22

0.000739

1.5

14.93

0.23

 

VINA1@19

100

32,000

320

1019

8

0.383

2.5

0.000655

1.6

1.5

0.000631

1.6

12.74

0.20

0.000646

1.6

13.04

0.21

 

VINA1@21

24

19,000

786

760

11

0.594

2.9

0.000744

1.5

3.0

0.000706

1.6

14.26

0.22

0.000722

1.5

14.58

0.23

B

VINA1@06

28

8200

290

1538

19

0.190

6.0

0.000788

1.6

0.7

0.000768

1.7

15.51

0.26

0.000782

1.6

15.81

0.26

VINA1@07

28

8300

295

1741

20

0.209

5.9

0.000775

1.6

0.7

0.000758

1.6

15.31

0.25

0.000769

1.6

15.55

0.25

VINA1@08

22

7100

326

1211

19

0.203

6.4

0.000732

1.6

0.8

0.000709

1.7

14.32

0.24

0.000727

1.6

14.68

0.24

VINA1@09

29

6800

235

1132

19

0.209

6.4

0.000754

1.6

0.8

0.000728

1.6

14.72

0.24

0.000748

1.6

15.12

0.24

VINA1@10

29

7300

252

1192

19

0.194

6.7

0.000748

1.6

0.7

0.000724

1.6

14.63

0.24

0.000743

1.6

15.01

0.24

C1

VINA1@11

23

2800

121

346

15

0.508

3.3

0.000879

1.8

9.9

0.000781

2.3

15.78

0.37

0.000792

1.8

16.01

0.29

VINA1@12

29

1900

65

816

30

0.130

7.5

0.000746

1.8

1.6

0.000725

2.4

14.64

0.35

0.000734

1.8

14.83

0.27

VINA1@13

23

1800

79

903

33

0.132

8.2

0.000740

2.3

1.6

0.000708

2.6

14.30

0.37

0.000728

2.3

14.71

0.33

VINA1@14

21

2500

119

1008

28

0.122

9.1

0.000778

2.0

0.8

0.000749

2.2

15.12

0.33

0.000772

2.0

15.60

0.31

VINA1@15

14

2400

169

590

23

0.274

5.3

0.000805

1.9

3.8

0.000752

2.4

15.20

0.36

0.000775

1.9

15.65

0.30

VINA1@16

19

2700

144

1390

33

0.164

7.9

0.000784

1.8

1.2

0.000762

2.0

15.40

0.30

0.000775

1.8

15.65

0.28

C2

VINA1@01

28

4200

150

1189

24

0.113

8.0

0.000751

1.6

0.6

0.000727

1.8

14.69

0.26

0.000747

1.6

15.09

0.25

VINA1@02

33

4100

124

1905

31

0.116

8.4

0.000708

1.7

0.6

0.000697

1.8

14.09

0.25

0.000704

1.7

14.23

0.24

VINA1@03

27

3700

139

1344

28

0.140

8.3

0.000716

1.7

0.8

0.000696

1.9

14.06

0.27

0.000711

1.8

14.36

0.25

VINA1@04

15

3900

258

1327

27

0.160

7.9

0.000714

1.9

0.9

0.000697

2.0

14.07

0.28

0.000708

1.9

14.30

0.27

VINA1@05

30

3600

119

1168

27

0.136

8.4

0.000706

1.8

0.8

0.000682

1.9

13.79

0.27

0.000700

1.8

14.14

0.25

A

GESS1@25

47

7200

152

557

12

0.305

3.3

0.000796

2.0

3.2

0.000741

2.1

14.97

0.31

0.000771

2.0

15.57

0.32

GESS1@26

17

1500

88

130

13

0.591

2.5

0.001153

2.3

30.3

0.000810

4.1

16.36

0.66

0.000803

2.6

16.23

0.41

GESS1@27

19

4900

256

481

16

0.398

4.0

0.000797

2.1

4.4

0.000733

2.3

14.81

0.34

0.000762

2.1

15.39

0.33

 

GESS1@24

23

1200

51

145

16

0.439

3.6

0.000746

2.3

19.1

0.000547

4.6

11.06

0.50

0.000603

2.5

12.19

0.30

B

GESS1@01

28

2300

83

599

33

0.162

7.5

0.000769

2.2

3.2

0.000720

3.0

14.54

0.43

0.000745

2.2

15.05

0.33

GESS1@02

86

3600

42

531

32

0.209

6.7

0.000805

2.5

4.4

0.000759

3.4

15.33

0.52

0.000769

2.5

15.53

0.39

GESS1@03

160

7800

49

798

30

0.126

7.5

0.000721

2.0

1.7

0.000686

2.4

13.86

0.34

0.000709

2.1

14.32

0.29

GESS1@06

17

1200

69

428

22

0.224

5.9

0.000751

2.7

3.5

0.000683

3.2

13.80

0.44

0.000724

2.7

14.63

0.40

GESS1@10

21

3800

185

633

13

0.437

3.1

0.000811

1.9

4.0

0.000761

2.0

15.38

0.31

0.000778

1.9

15.72

0.31

GESS1@11

23

3300

141

922

17

0.162

6.0

0.000708

1.9

0.9

0.000679

2.0

13.71

0.27

0.000702

1.9

14.19

0.28

GESS1@12

23

3300

142

1520

22

0.235

5.3

0.000726

1.9

1.3

0.000707

2.0

14.29

0.28

0.000716

1.9

14.47

0.28

GESS1@15

50

1400

28

535

20

0.112

4.7

0.000769

2.2

2.4

0.000714

2.5

14.42

0.36

0.000751

2.2

15.17

0.33

GESS1@16

52

1200

23

1089

28

0.093

5.1

0.000768

2.2

1.8

0.000741

2.3

14.98

0.35

0.000754

2.2

15.24

0.33

GESS1@17

55

1500

27

755

24

0.104

4.9

0.000774

2.0

2.1

0.000735

2.3

14.85

0.34

0.000758

2.0

15.31

0.31

GESS1@18

42

1100

26

1062

36

0.104

6.3

0.000748

2.2

2.2

0.000721

2.5

14.56

0.36

0.000732

2.2

14.78

0.33

GESS1@19

43

3200

75

225

9

0.531

1.9

0.000884

2.0

14.9

0.000732

2.2

14.79

0.33

0.000752

2.0

15.20

0.30

GESS1@20

61

2400

39

355

13

0.316

2.7

0.000806

2.1

8.3

0.000718

2.4

14.52

0.35

0.000739

2.2

14.94

0.32

GESS1@23

59

2100

36

161

10

0.418

2.2

0.000885

2.8

17.2

0.000673

3.1

13.60

0.42

0.000732

2.8

14.80

0.41

 

GESS1@05

19

890

47

415

25

0.137

7.4

0.000689

2.4

2.5

0.000625

3.2

12.63

0.41

0.000671

2.4

13.56

0.33

 

GESS1@08

26

1200

45

982

31

0.178

6.9

0.000671

2.1

2.1

0.000644

2.4

13.02

0.31

0.000656

2.1

13.26

0.28

 

GESS1@09

25

1500

59

954

27

0.166

6.7

0.000697

2.4

1.7

0.000669

2.6

13.51

0.35

0.000685

2.4

13.84

0.33

 

GESS1@21

74

2300

31

1030

23

0.099

5.7

0.000684

2.0

1.1

0.000658

2.1

13.30

0.28

0.000676

2.0

13.66

0.28

 

GESS1@22

59

1200

21

319

19

0.215

4.5

0.000729

2.3

6.3

0.000640

3.1

12.94

0.40

0.000682

2.3

13.78

0.32

 

GESS1@04

180

7700

43

884

36

0.116

7.8

0.000618

2.2

2.1

0.000591

2.6

11.94

0.31

0.000605

2.2

12.23

0.27

 

GESS1@07

23

700

30

609

32

0.160

7.4

0.000614

2.4

2.9

0.000584

3.1

11.80

0.36

0.000596

2.4

12.05

0.29

 

GESS1@13

31

3900

127

1425

22

0.190

6.5

0.000641

1.9

0.9

0.000624

2.0

12.60

0.25

0.000636

1.9

12.84

0.25

 

GESS1@14

26

2700

105

2697

47

0.144

10.0

0.000637

2.1

0.8

0.000628

2.2

12.68

0.28

0.000632

2.1

12.77

0.27