USING THE SUNSPOT CYCLE TO DATE ICE CORES

For many ice cores, the snow accumulation rate is too low to preserve annual stratigraphy, precluding direct measurement of annual layer thi ckness. For selected Holocene sections of the Taylor Dome core, East A ntarctica, we instead use high-resolution Be-10 measurements to establ ish a nominal 11-year thickness, taking advantage of the solar cycle i n cosmogenic isotope production. We compare measured thicknesses with the layer thickness profile predicted by a finite element ice flow mod el. The results are in good agreement, supporting the assumption that the length of the solar cycle has remained essentially constant throug hout the Holocene. For ice cores where annual layers are not preserved , the Be-10 11-year layer method can be used as an independent check o n flow-model estimates of layer thickness and to estimate past accumul ation rates. It should be possible to accurately date ice cores by cou nting 11-year layers detected with continuous high-resolution Be-10 me asurements.