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207
Pb
a
U
b
Pb
b
Th
b 206
Pbc
c 207
Pb
d
±2s
206
Pb
d
±2s ȡ
e
207
Pb
d
±2s
206
Pb
f
±2s
207
Pb
f
±2s
207
Pb
f
±2s Conc.
g
(cps) (ppm) (ppm)
U (%)
235
U (%)
238
U (%) (rho)
206
Pb (%)
238
U (Ma)
235
U (Ma)
206
Pb (Ma) (%)
Grain
Felix
h
12482 435 68 2.47 0.2 0.6484 3.0 0.08211 3.0 0.43 0.05728 3.0 509 15 507 12 502 65 102
Plesovice
h
2852 651 34 0.09 1.3 0.3989 4.1 0.05419 2.2 0.48 0.05339 2.9 340 7 341 12 345 64 99
206
Pb/
238
U error is the quadratic additions of the within run precision (2 SE) and the external reproducibility (2 SD) of the reference zircon.
207
Pb/
206
Pb error propagation
(
207
Pb signal dependent) following Gerdes & Zeh (2009).
207
Pb/
235
U error is the quadratic addition of the
207
Pb/
206
Pb and
206
Pb/
238
U uncertainty.
a
Within run background-correctedmean
207
Pb signal in cps (counts per second).
b
U and Pb content and Th/U ratio were calculated relative to GJ-1 reference zircon.
c
Percentage of the common Pb on the
206
Pb. b.d. = below detection limit.
d
Pb/U and Pb/Pb ratios. Corrected for background, within-run Pb/U fractionation (in case of
206
Pb/
238
U) and common Pb using Stacy and Kramers (1975) model Pb
composition and subsequently normalised to GJ-1 (ID-TIMS value/measured value);
207
Pb/
235
U calculated using ((
207
Pb/
206
Pb)*(
238
U/
206
Pb)*137.88).
e
ZŚŽ ;ʌͿ ŝƐ ƚŚĞ ;
206
Pb/
238
U)/(
207
Pb/
235
U) error correlation coefficient.
f
Pb/U and Pb/Pb ages.
g
Degree of concordance = ((
206
Pb/
238
U age)/(
207
Pb/
206
Pb age)) x 100.
h
Mean of 13 (91500), 13 (Felix), 13 (Plesovice), and 23 (GJ-1) analyses, respectively.
230