Table 2.

U–Pb and Pb-Pb data for Khoy flaser gabbros

Properties*Weight (µg)U (ppm)Pbi (ppm)206/204§207/235||2σ (abs)||206/238||2σ (abs)||rho||207/206||2σ (abs)||206/238 (Ma)||2σ (abs)||207/235 (Ma)||2σ (abs)||238/2042σ (%)206/2042σ (%)235/2042σ (%)207/2042σ (%)
KY15-1; flaser gabbro (GPS data: N38.35.85, E44.57.00)
RUT441.460.0729.0750.2480.0440.022570.000610.320.07970.0136143.93.8225.035.114147.750.435.710.257.718.292.9
RUT391.780.0430.8620.0360.0850.020890.000880.900.01250.0282133.35.635.979.6276117.776.7815.720.0217.716.4711.7
RUTILE4321.920.2130.2620.1250.0170.021470.000150.650.04220.0054137.00.9119.514.9581.960.531.0230.34.2210.516.2750.4
RUT + TIT8083.790.8225.3210.1410.0250.023150.000190.510.04420.0076147.51.2133.921.9296.130.425.3810.12.1480.416.0510.2
TIT4331.699.5018.77011.3190.218.7700.10.0820.215.7160.2
HBL10330.010.6318.5510.8731.018.5490.20.0061.015.7490.2

* RUT, rutile; TIT, titanite; HBL, hornblende.

Weight and concentrations are known to better than 10%.

Pbi is initial Pb (corrected for blank).

§ Raw data, corrected for fractionation and spike.

|| Corrected for fractionation, spike, blank (206/204 = 18.59; 207/204 = 15.24) and initial common Pb (the hornblende Pb composition); error calculated by propagating the main sources of uncertainty. The U–Pb ratio of the spike used for this study is adapted to 206Pb/238 U = 0.015660 for the ET100 solution as obtained with the ET2535 spike at NIGL.

Corrected for fractionation, spike and blank.