MEASUREMENTS OF THE (CO2)-C-14 BOMB PULSE IN FIRN AND ICE AT LAW-DOME, ANTARCTICA

(CO2)-C-14 produced in tile atmosphere by nuclear weapons testing in t he 1960's is now incorporated in the air bubbles of Antarctic ice, The high atmospheric radiocarbon growth rates through the period of tests and subsequent decline provide a unique and independent test for the smoothing of atmospheric CO2 signals due to firn diffusion and bubble close off, The level of smoothing quantifies the time resolution with which atmospheric trace gas histories can be reconstructed from ice co res, In this paper, the methodologies for the preparation and AMS meas urements of ice core and firn (CO2)-C-14 from high accumulation sites at Law Dome are detailed, The results are compared with predictions of a numerical model incorporating firn air diffusion and bubble close-o ff. The sample sizes, precision of measurements and sources of contami nation are discussed for both firn and ice samples.