Table 5. Ion microprobe U-Th-Pb analytical data for zircons from Khoboy granulite sample 03210
Grain	238U	232Th	Th/U	f204	238U/206Pb	207Pb/206Pb 	238U/206Pb age	207Pb/206Pb age	
Area	(ppm)	(ppm)		(%)		(±1s)		(±1s)	(Ma)	(±1s)	(Ma)	(±1s)	
session 1	
1.1c	242	133	0.57	0.153	5.624	0.171	0.07291	0.00101	1055	30	1012	28	
2.1r	383	86	0.23	0.336	12.938	0.141	0.05541	0.00082	479.9	5.0	429	33	
2.2c	407	120	0.30	0.001	3.153	0.066	0.16308	0.00066	1776	33	2488	7	
3.1r	269	72	0.28	0.524	13.273	0.151	0.05176	0.00147	468.2	5.1	275	65	
3.2c	173	73	0.44	0.099	5.894	0.307	0.10970	0.00362	1010	49	1794	60	
*4.1r	206	126	0.63	0.948	12.209	0.144	0.05620	0.00276	507.5	5.8	460	109	
4.2c	113	48	0.44	0.519	12.767	0.172	0.06325	0.00354	486.1	6.3	717	119	
5.1r	899	327	0.38	0.012	11.930	0.127	0.05729	0.00040	518.9	5.3	503	15	
5.2c	3380	2013	0.62	0.012	11.548	0.119	0.05783	0.00025	535.4	5.3	523	9	
6.1r	437	93	0.22	0.006	13.228	0.139	0.05692	0.00056	469.8	4.8	488	22	
6.2c	310	168	0.56	0.056	8.424	0.269	0.06565	0.00079	723.2	22	795	25	
7.1c	212	52	0.25	0.033	4.206	0.049	0.10186	0.00069	1375	15	1658	13	
*8.1r	161	94	0.60	0.666	12.671	0.152	0.05366	0.00218	489.7	5.6	357	92	
*16.1r	679	320	0.49	0.065	12.238	0.126	0.05722	0.00052	506.4	5.0	500	20	
9.1c	146	48	0.34	-0.039	7.364	0.200	0.06764	0.00188	820.8	21	857	58	
10.1c	142	80	0.58	0.168	6.705	0.081	0.06654	0.00136	896.2	10	823	43	
11.1r	448	1083	2.50	2.432	14.732	0.233	0.05803	0.00606	423.4	6.5	531	229	
12.1r	571	39	0.07	0.067	11.508	0.121	0.05730	0.00070	537.2	5.4	503	27	
*13.1r	597	32	0.06	0.072	12.461	0.141	0.05796	0.00070	497.6	5.4	528	27	
*14.1r	1314	186	0.15	0.642	12.420	0.124	0.05700	0.00071	499.2	4.8	492	27	
15.1c	701	159	0.23	-0.099	9.890	0.102	0.06116	0.00061	620.9	6.1	645	22	
17.1r	383	67	0.18	0.120	13.556	0.144	0.05522	0.00089	458.8	4.7	421	36	
session 2	
*18.1r	544	47	0.09	0.428	12.659	0.209	0.05370	0.00140	490.1	7.8	359	59	
18.2c	182	47	0.27	0.079	1.381	0.073	0.19120	0.00615	3511	143	2753	53	
19.1r	584	145	0.26	0.733	12.946	0.222	0.05642	0.00241	479.7	7.9	469	95	
19.2c	155	126	0.84	0.519	7.179	0.312	0.07140	0.00445	840.7	34	969	127	
20.1r	129	30	0.24	17.769	11.837	0.422	0.03937	0.02651	522.8	18	---	---	
*21.1r	214	72	0.35	0.768	12.743	0.192	0.05194	0.00299	487.0	7.1	283	132	
22.1r	5396	586	0.11	0.027	12.839	0.115	0.05665	0.00028	483.5	4.2	478	11	
Notes: Grain area: r = rim, c = core. f204 is the proportion of common 206Pb in measured 206Pb, as determined by measured 204Pb. Isotope ratios and ages are corrected for common Pb. Uncertainties in 238U/206Pb ratios and ages do not include uncertainty (1s) of 0.30% for session 1 and 0.38% for session 2, arising from calibration against the reference standard. Zircon rim analyses marked with asterisks were included in calculating the mean age for the coherent grouping at 498 Ma.