9221836 Dibb This two objectives of this project are to develop a rugged, portable gamma ray detector system that can be used to make rapid in situ measurements of Cesium-137 in snow and ice, and to test the system in Antarctica in conjunction with other ice coring and snow sampling programs to verify and calibrate the in situ measurements. These measurements will provide an accurate means of determining the snow accumulation rate, a critical component of glaciological mass balance studies. The identification of horizon markers of known absolute age is basic to such studies. On the century time scale, the deposition of Cesium-137 has produced horizons at the time of the initiation of atmospheric thermonuclear testing in 1953, at the time of maximum testing in 1963, and the Chernobyl accident in 1986. Cesium-137 has a half life of 30.2 years. This gamma ray detection technique is expected to locate horizons quickly and unambiguously in the field, and can be used both in polar ice sheets, and in high altitude temperate zone snow fields. ***
