Geologic map of the Leadville North 7.5’ quadrangle, Eagle and Lake Counties, Colorado

CR–CO–LN–01–14 39.2750272 106.346184 3236 3 2.73 0.9999 0 0.2766 25.271 970±22 7.07±0.16 47.40±1.25 6.70±0.23 20.66±0.48 2.32 21.29±0.57 2.66 1.03 CR–CO–LN–02–14 39.2748902 106.347121 3030 3 2.73 0.9999 0 0.2783 41.551 1,475±26 6.59±0.12 44.20±1.16 6.71±0.21 19.45±0.35 1.78 20.04±0.53 2.65 1.03 CR–CO–LN–03–14 39.2760246 106.348754 3030 3 2.73 0.9999 0 0.2791 30.354 977±33 5.98±0.20 40.80±1.27 6.82±0.31 17.81±0.60 3.36 18.68±0.59 3.14 1.05 Cblk–3509–1 -------0.2808 -4±01 --------CR–CO–HR–06–11 39.3550122 106.370884 3248 3 2.73 0.9996 0 0.2697 15.703 539±15 6.14±0.17 44.60±1.93 7.26±0.37 15.96±0.44 2.73 17.85±0.78 4.37 1.12 CR–CO–LN–01–11 39.3415053 106.368624 3236 3 2.73 0.9999 0 0.2875 27.647 978±24 6.76±0.17 46.00±1.65 6.80±0.30 17.63±0.45 2.52 18.50±0.67 3.62 1.05 CR–CO–LN–02–11 39.3209233 106.340185 3036 3 2.73 0.9995 0 0.2801 19.716 815±14 7.69±0.14 51.40±1.41 6.68±0.22 22.17±0.39 1.78 22.83±0.63 2.77 1.03 CR–CO–LN–03–11 39.3231251 106.341468 3036 3 2.73 0.9995 0 0.2825 20.025 1,119±21 10.50±0.20 69.20±2.19 6.59±0.24 29.55±0.56 1.91 30.04±0.97 3.21 1.02 CR–CO–LN–04–11 39.33184 106.354525 3067 3 2.73 0.9998 0 0.2818 39.845 1,358±21 6.40±0.10 43.00±1.18 6.72±0.21 18.52±0.29 1.57 19.14±0.53 2.77 1.03 CR–CO–LN–05–11 39.3305518 106.35682 3064 3 2.73 0.9992 0 0.2842 24.561 763±21 5.87±0.16 39.10±1.30 6.66±0.29 17.12±0.48 2.79 17.58±0.59 3.36 1.03 Cblk–3436–2 -------0.2876 -5±1 --------Cblk–3436–1 -------0.2828 -4±1 --------Blank sample measured for instrument calibration. Table 1. Be and Al cosmogenic radionuclide sample data and age analyses. Sampling was carried out following established procedures outlined in Gosse and Phillips (2001). This included recording elevation, latitude, longitude, and topographic shielding data for each sample location, which accounts for any hindrance to Be and Al production from the surrounding skyline. Ages of samples were calculated using the CRONUS-Earth online calculator V.2.2 following the time-invariant scaling model of Lal (1991) and Stone (2000). Uncertainties are reported at the 1 sigma (σ) (±9 percent external uncertainty; Balco and others, 2008). Consistent with past studies within the region, no corrections for erosion or snow cover were applied, which allows for comparison with previous Be chronologies reported for the upper Arkansas River valley and central Colorado (Guido and others, 2007; Briner, 2009; Ward and others, 2009; Young and others, 2011) when adjustments for production rates are made. 39° 39°30'