| Cosmogenic dating has enabled direct dating of glacial landforms and deposits, greatly
improving our understanding of past glaciations in terms of timing as well as glacial erosion
and preservation. Over the last 25 years a large (and growing) number of publications have
reported cosmogenic exposure ages from glacial landforms around the world. Here a global
compilation of glacial 10Be and 26Al exposure ages will be presented aiming at an
analysis and quantification of cosmogenic dating uncertainties. The dataset consists of
>9300 10Be exposure ages and >1400 26Al exposure ages with full input data
(location, elevation, sample type, sample thickness, concentration, standardization etc.).
All exposure ages have been recalculated with updated reference production rates
and organized in discrete glacial landform groups enabling evaluation of exposure
age scatter due to prior and incomplete exposure. Exposure age scatter is common
and increase significantly for glacial landforms older than the global last glacial
maximum, making precise cosmogenic dating of older glaciations difficult. The
data will be used to evaluate exposure dating of different sample types (boulder
vs bedrock surfaces) and sample selection based on boulder size. Exposure ages
from the paleo-ice sheets will be compared with mountain glacier exposure ages,
aiming at picking out the good (well-clustered) exposure ages. The full dataset will
eventually be posted online and continuously updated with published exposure age data. |