Expected in-situ 14C is based on 14C production rate at surface for the present altitude (3.2 km), 200 atoms 14C/g ice/y (Jull et al., 1994), and model ice accumulation rates estimated by Cutler et al. (1995). The estimates are in-situ cosmogenic 14C (i.e. excluding trapped 14C). For total - trapped CO2, the amount of trapped 14CO2 is estimated from the amount of air in the ice (tab1) and assuming 250 ppm CO2 in air.