Evidence for two intervals of enhanced 10Be deposition in Antarctic ice during the last glacial period
Abstract
We have previously reported concentration profiles of cosmic ray produced (cosmogenic) 10Be in deep ice cores from Dome C and Vostok, Antarctica1,2. In both these cores we found a concentration of 10Be approximately two times larger in ice from the late glacial period than in the Holocene ice. We interpreted this as probably resulting from a lower precipitation rate on the Antarctic plateau during glacial periods, compared to interglacial periods. In the Vostok profile there was one sample, corresponding to ~60,000 yr BP, which gave an unusually large 10Be concentration, not correlated with any obvious climatic event. We suggested that this sample might be reflecting increased 10Be production, as for example during a period of reduced solar modulation2. We have now measured a much more detailed concentration profile for 10Be in the Vostok core. The results confirm a 10Be 'peak', lasting ~1,000-2,000 years, at ~60,000 yr BP, and show another similar peak at ~35,000 yr BP. We have also observed the latter peak in the Dome C core. We discuss possible sources for these peaks, and their potential as stratigraphic markers.
- Publication:
-
Nature
- Pub Date:
- March 1987
- DOI:
- 10.1038/326273a0
- Bibcode:
- 1987Natur.326..273R
- Keywords:
-
- Antarctic Regions;
- Beryllium 10;
- Deposition;
- Glaciology;
- Land Ice;
- Planetary Evolution;
- Cosmic Rays;
- Isotopic Enrichment;
- Mass Spectroscopy;
- Solar Terrestrial Interactions;
- Vertical Distribution;
- Geophysics