Table 2.

Ion microprobe U–Pb zircon analyses of inherited zircons

Sample spotU (ppm)Th (ppm)204/206% error207Pb/206Pb% error206Pb/238U% errorAge (Ma)*Error ± (Ma)†
Upper Unit
CS021-1.22821460.00019939.50.0503941.80.0937431.72423
CS021-2.22572540.00005243.20.1245940.40.8573352.0189620
CS021-13.1102420.0452646.20.0262951.71803
CS021-17.215793160.00007699.00.0496681.60.0184294.1491
CS021-19.161250.00109141.60.0610513.30.0998102.12894
CS021-23.11841100.1123151.10.7411351.3165818
Middle Unit (western plateau)
CS018-2.11891420.0477553.50.0344971.11021
CS018-3.15331840.00021749.50.0539192.40.0234241.8681
CS018-4.11531410.00063440.80.0527613.50.0374522.61031
CS018-6.21561170.00059337.80.0540892.90.0534951.51382
CS018-7.293890.0549094.50.0363413.11052
CS018-12.197570.00568447.60.0803527.40.0092132.9251
CS018-18.12673250.00048944.70.0524084.10.0152042.4411
CS018-23.19913850.00002399.00.0501931.00.0412086.91232
CS018-10.21981300.00019179.90.0521042.40.0428332.71211
CS018-16.26193820.00003999.00.0493401.10.0633821.61732
CS018-20.24413380.00025638.30.0510251.30.0569933.71872
CS020-6.13272340.0489542.60.0414531.81131
CS020-7.21189558−0.00006260.90.0495651.20.0537061.81401
Middle Unit (eastern plateau)
CS072-14.22381360.00019656.60.0525012.10.0454372.61421
CS072-16.21701350.00048040.80.0524392.60.0407861.91141
CS072-19.24353490.00015872.50.0505671.90.0308333.01211
CS072-22.14182310.00058753.30.0535722.70.0165575.3431
Lower Unit
CS054-3.12601110.00007254.10.0562561.10.1769411.54697
CS054-4.183370.00178533.30.0875913.30.0420863.31082
CS054-5.169178−0.00005760.90.0705951.30.3766292.297011
CS054-7.189690.00079335.40.0528364.30.0671081.21822
CS054-8.12331150.00054040.60.0469092.90.0374063.11051
CS054-16.1133159−0.00040367.90.0475093.50.0475642.31302
Aplite dyke
CS007-6.270610.00021099.00.0484175.60.0445573.01152
CS007-10.294840.00059978.60.0479034.60.0483191.91222
  • * Based on 207Pb-corrected 206Pb/238U age.

  • † Errors are 1σ.