282 / 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.
(cps) (ppm) (ppm)
U (%)
235
U (%)
238
U (%) (rho)
206
Pb (%)
238
U (Ma)
235
U (Ma)
206
Pb (Ma) (%)
Grain
A143 83708 190 78 0.15 b.d.
8.6590 1.1 0.3947 0.6 0.59 0.1591 0.9 2145 12 2303 10 2446 15 88
A087 79415 347 140 0.34 0.4 8.6980 2.0 0.3636 1.1 0.57 0.1735 1.6 1999 19 2307 18 2592 27 77
A141 12930 29 15 1.57 1.1 8.7890 2.0 0.3978 1.3 0.63 0.1602 1.5 2159 23 2316 18 2458 26 88
A056 31360 109 50 0.42 0.1 9.5390 1.0 0.4129 0.7 0.69 0.1676 0.7 2228 13 2391 9 2533 12 88
A074 89065 178 81 0.52 0.1 9.6900 1.0 0.3978 0.6 0.61 0.1767 0.8 2159 12 2406 9 2622 13 82
91500
h
9367 69 13 0.46 0.6 1.8167 9.0 0.1777 2.9 0.28 0.0741 8.1 1055 28 1051 59 1043 166 102
Felix
h
4705 227 26 1.76 0.6 0.6073 10.8 0.0813 4.8 0.27 0.0542 8.9 504 23 482 42 376 206 151
Plesovice
h
1707 575 30 0.12 0.2 0.4114 2.2 0.0555 2.4 0.41 0.0538 0.6 348 8 350 6 361 13 97
GJ-1
h
7212 286 26 0.02 0.1 0.8151 1.5 0.0984 0.5 0.31 0.0601 1.5 605 3 605 7
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 12 (91500), 13 (Felix), 13 (Plesovice), and 26 (GJ-1) analyses, respectively.
266