Table 7.

LA-ICP-MS U–Pb isotope data and dates for concordant analyses of zircon in sample 55-L

PointPositionTh (ppm)U (ppm)Th/U207Pb/235U206Pb/238Urho207Pb/235U206Pb/238U
Ratio(±1σ)Ratio(±1σ)Date (Ma)(±1σ)Date (Ma)(±1σ)
55-L_32R11.4774.60.0150.0280.00270.0040.00010.2028.52.723.50.4
55-L_33R66.62074.40.0320.0200.00150.0040.00000.1619.81.522.90.3
55-L_31R53.81670.50.0320.0260.00190.0040.00010.2325.91.922.70.4
55-L_15R17.41637.40.0110.0240.00180.0030.00000.1823.71.822.50.3
55-L_19R36.31880.00.0200.0210.00150.0030.00000.1921.41.522.30.3
55-L_29R80.41245.10.0650.0220.00190.0030.00010.1721.81.922.30.3
55-L_37R81.12422.50.0330.0230.00130.0030.00000.2422.91.322.10.3
55-L_22R10.8892.10.0130.0270.00300.0030.00010.2027.43.022.00.5
55-L_21R12.2830.20.0150.0230.00240.0030.00010.1723.32.421.80.4
55-L_24R75.21228.70.0640.0200.00210.0030.00010.1520.22.121.80.3
55-L_23R13.9783.10.0180.0260.00240.0030.00010.2226.42.421.70.4
55-L_03R90.21230.10.0760.0230.00190.0030.00010.2123.21.921.50.4
55-L_26R70.5808.80.0870.0210.00280.0030.00010.1520.92.820.60.4
55-L_18R20.8504.80.0430.0260.00580.0030.00010.1525.95.720.20.7
55-L_13R39.6433.80.0950.0340.00440.0030.00010.2233.94.320.10.6
55-L_10R51.3737.90.0720.0320.00330.0030.00010.2431.93.220.00.5
55-L_05R41.92336.60.0190.0200.00120.0030.00000.2119.91.220.00.3
55-L_02R75.9509.60.1550.0240.00380.0030.00010.1523.93.719.60.5
55-L_09R66.0364.30.1880.0360.00520.0030.00010.2035.85.119.40.6
55-L_27R32.2416.40.0770.0300.00560.0030.00010.1630.25.519.30.6
55-L_25R28.7346.80.0830.0310.00520.0030.00010.1931.15.119.20.6
55-L_34R28.9773.70.0370.0160.00240.0030.00010.1516.42.419.10.4
55-L_12R30.6635.10.0500.0290.00320.0030.00010.2228.63.219.10.5
55-L_16R87.9300.40.3040.0350.00600.0030.00010.2134.95.918.80.7
55-L_06R45.61418.70.0330.0180.00180.0030.00000.1718.31.818.70.3
55-L_28R49.0500.50.0980.0360.00360.0030.00010.2535.83.518.50.5
55-L_04R51.7484.60.1110.0320.00420.0030.00010.2232.14.118.30.5
55-L_30R41.03500.40.0120.0180.00090.0030.00000.2117.90.918.20.2
55-L_20R94.6372.90.2640.0230.00450.0030.00010.1522.84.517.80.5
55-L_35R37.3465.10.0800.0310.00500.0030.00010.1830.74.917.30.5
55-L_11R52.7449.30.1220.0200.00400.0030.00010.1420.24.016.80.5