文摘
The production, accumulation, and decay of cosmogenic radionuclides in rock surfaces subjected to episodes of exposure and burial by ice results in nuclide concentrations in present day rock surfaces that can be used to address a variety of questions in glacial geomorphology and Quaternary geology. Of particular importance is the fact that these nuclide concentrations reflect both the timing of initial exposure of the rock surface and the chronology of subsequent exposure, burial, and erosion episodes. For landscapes where geomorphic evidence indicates that little/no erosion occurred, constraining the timing of initial exposure and the number of phases of exposure and burial that a rock surface has been subjected to is possible using multiple cosmogenic radionuclide concentrations combined with proxies for the timing and duration of periods of ice cover, such as ice core or marine isotope records. However, interpretations based on this approach require determination of an appropriate cutoff value to separate the proxy record into ice-free and ice-covered conditions and assessment of the sensitivity of the results to different cutoff values.
