Abstract

Valley glacier moraines are commonly used to infer past mean annual precipitation and mean melt-season temperature. However, recent research has demonstrated that, even in steady climates, multi-decadal, kilometer-scale fl uctuations in glacier length occur in response to stochastic, year-to-year variability in mass balance. When interpreting moraine sequences it is important to include the effect of interannual weather variability on glacier length; moraines record advances that are forced either by interannual variability or by a combination of climate change and interannual variability. We address this issue for the Last Glacial Maximum (LGM) glaciers of the Colorado Front Range, United States. Using a linear glacier model that allows thorough exploration of parameter uncertainties, supplemented by a shallow-ice fl owline model, our analyses suggest that (1) glacial standstills longer than 50 years were unlikely; (2) mean glacier lengths are ~10%–15% up-valley from maximum glacier lengths; and (3) individual LGM terminal moraines were formed by a combination of a climate change and interannual variability–forced advances.

Citation

Anderson, L., Roe, G., and Anderson R. (2014): The effects of interannual climate variability on the moraine record. Geology 42(1): 55-58. DOI: 10.1130/G34791.1

This Paper/Book acknowledges NSF CZO grant support.