West Greenland and global in situ 14C productionrate calibrations

The in situ cosmogenic nuclide C is unique compared with other nuclides because of its short halflife, and when combined with longer-lived isotopes (e.g. Be), in situ C can be a powerful tool for deciphering recent and complex surface exposure histories. Like all in situ cosmogenic nuclides, quantifying earth surface processes with in situ C requires a well-constrained in situ C production rate. We present a production-rate calibration from an independently dated moraine in West Greenland, previously used as an in situ Be production-rate calibration site. The local in situ C production rate is 22.8 1.4 atoms g 1 a 1 (69.28 ̊N, 50.76 ̊ W; 350m asl) and when scaled to sea level/high latitude using time-dependent Lal/Stone scaling (Lm), we calculate a spallation-only in situ C production rate of 12.0 0.9 atoms g 1 a 1 and a C/Be production rate ratio of 3.1 0.2. The West Greenland in situ C production rate is indistinguishable from the New Zealand, Promontory Point and Scottish Highlands in situ C production rates. When combined, we calculate a global production rate of 12.1 0.5 atoms g 1 a 1 (Lm). Copyright # 2014 John Wiley & Sons, Ltd.