Sample No.

Weight (mg)

Concentration (ppm)

Pb isotope composition¹⁾

Isotope ratios²⁾

Age, Ma²⁾

Pb

U

²⁰⁶Pb/²⁰⁴Pb

²⁰⁶Pb/²⁰⁷Pb

²⁰⁶Pb/²⁰⁸Pb

²⁰⁷Pb/²³⁵U

²⁰⁶Pb/²³⁸U

²⁰⁷Pb/²⁰⁶Pb

Anorthosites of the Imandra lopolith

1034-1 (bd)

1.0

174.6

410.7

6280

6.316

87.0

9.108

0.4219

2419

1034-2 (bd)

0.8

330.6

790.5

14,210

6.351

93.5

9.000

0.4162

2422