FF52-9040 K-feldspar (J = 0.000435) Total gas age = 1.04 ± 0.01 Ma

step

T

(° C)

⁴⁰Ar/³⁹Ar

³⁷Ar/³⁹Ar

³⁶Ar/³⁹Ar

³⁹Ar

(mol)

S³⁹Ar

(%)

⁴⁰Ar*

(%)

Age ± 1s

(Ma)

1

450

30.96

3.24E-02

9.47E-02

5.34E-15

1.60

9.60

2.33 ± 0.09

2

500

8.244

2.05E-02

2.49E-02

8.34E-15

4.10

10.6

0.69 ± 0.04

3

550

4.626

1.68E-01

1.31E-02

1.30E-14

8.00

16.4

0.60 ± 0.02

4

600

3.683

6.25E-02

9.65E-03

1.13E-14

11.4

22.6

0.65 ± 0.02

5

650

3.192

4.00E-02

7.43E-03

1.87E-14

17.0

31.1

0.78 ± 0.01

6

700

2.939

6.23E-03

6.38E-03

1.57E-14

21.7

35.7

0.82 ± 0.01

7

750

3.064

5.77E-03

6.23E-03

1.67E-14

26.7

39.8

0.96 ± 0.01

8

800

3.185

5.62E-03

6.58E-03

1.73E-14

31.9

38.9

0.97 ± 0.01

9

850

1.848

2.30E-02

1.80E-03

4.50E-14

45.4

71.1

1.03 ± 0.01

10

900

1.663

2.33E-03

9.85E-04

4.17E-14

57.9

82.3

1.07 ± 0.01

11

950

1.647

2.03E-02

7.53E-04

6.80E-14

78.3

86.3

1.11 ± 0.01

12

1000

1.722

1.54E-02

7.62E-04

4.40E-14

91.5

86.8

1.17 ± 0.01

13

1050

1.765

2.53E-02

8.84E-04

1.90E-14

97.2

85.1

1.18 ± 0.01

14

1100

2.076

2.15E-02

1.78E-03

4.67E-15

98.6

74.6

1.21 ± 0.03

15

1250

2.206

3.28E-02

1.63E-03

3.00E-15

99.5

78.0

1.35 ± 0.04

16

1400

3.277

7.10E-02

5.45E-03

1.33E-15

100

50.9

1.31 ± 0.09