320 / 352
207
Pb
a
U
b
Pb
b
Th
b 206
Pbc
c 207
Pb
d
±2
V
206
Pb
d
±2
V
ȡ
e 207
Pb
d
±2
V
206
Pb
f
±2
V
207
Pb
f
±2
V
207
Pb
f
±2
V
Conc.
g
(cps) (ppm) (ppm)
U (%)
235
U (%)
238
U (%) (rho)
206
Pb (%)
238
U (Ma)
235
U (Ma)
206
Pb (Ma) (%)
Grain
91500
h
8532 69 13 0.45 0.3 0.1784 3.8 1.8103 6.1 0.07 4.3867 0.6 1058 37 1049 40 1030 89 103
Felix
h
4019 203 23 1.93 0.4 0.0808 4.3 0.6109 10.3 0.05 7.7221 0.4 501 21 484 40 402 176 132
Plesovice
h
2881 1038 54 0.16 0.2 0.0549 3.8 0.4045 3.8 0.05 1.5557 0.5 344 13 345 11 348 35 99
GJ-1
h
6932 290 26 0.02 0.1 0.0984 1.1 0.8158 2.0 0.06 2.0856 0.5 605 6 606 9
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-corrected mean
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 11 (91500), 11 (Felix), 9 (Plesovice), and 26 (GJ-1) analyses, respectively.
304