Chlorine-36 and cesium-137 in ice-core samples from mid-latitude glacial sites in the Northern Hemisphere

Chlorine-36 (Cl-36) concentrations, Cl-36/Cl ratios, and Cl-36 fluxes in ic e-core samples collected from the Upper Fremont Glacier (UFG) in the Wind R iver Mountain Range, Wyoming, United States and the Nangpai Gosum Glacier ( NGG) in the Himalayan Mountains, Nepal, were determined and compared with p ublished results from the Dye-3 ice-core drilling site on the Greenland Ice Sheet. Cesium-137 (Cs-137) concentrations in the NGG also were determined. The background fluxes for Cl-36 for each glacial site were similar: (1.6 /- 0.3) x 10(-2) atoms/cm(2) s for the UFG samples, (0.7 +/- 0.1) x 10(-2) atoms/cm(2) s for the NGG samples, and (0.4 +/- 0.1) x 10(-2) atoms/cm(2) s for the Dye-3 samples. The Cl-36 fluxes in ice that was deposited as snow during peak atmospheric nuclear weapon test (1957-1958) were (33 +/- 1) x 1 0(-2) atoms/cm(2) s for the UFG site, (291 +/- 3) x 10(-2) atoms/cm(2) s fo r the NGG site, and (124 +/- 5) x 10(-2) atoms/cm(2) s for the Dye-3 site. A weapon test period Cs-137 concentration of 0.79 +/- 0.05 Bq/kg in the NGG ice core also was detected in the same section of ice that contained the l argest Cl-36 concentration. (C) 2000 Elsevier Science B.V. All rights reser ved.