Cosmogenic 3he helium age dating

Assuming basic elements of ice-dynamics and debris entrainment are known, the model results provide an estimate for the total accumulation of cosmogenic nuclides, as well as the expected range in nuclide inventories, for any clast at the surface of debris-covered glaciers.

Because the values are quantified, the approach can be applied to help evaluate the robustness of existing and future cosmogenic datasets applied to these systems.

The most common of these dating techniques is Cosmogenic radionuclide dating.

The exact knowledge of the age of the footprint enables archeologists to reconstruct the history of human settlement in the region.As a test, we applied our model framework towards Mullins Glacier, a cold-based debris-covered alpine glacier in the Dry Valleys of Antarctica.Our simulated values for cosmogenic-nuclide inventories compare well with those previously measured from fifteen surface cobbles along Mullins Glacier (He), both in terms of expected ranges and absolute values, and suggest that our model framework adequately incorporates most of the complicating factors that impact cosmogenic datasets for cold-based, debris-covered glaciers.In these cases, the measured Ne content (assumed to be derived solely from the atmosphere) can be used to calculate the additional He (He has to be determined from the isotope measurements of tritium-free water in the aquifer under investigation. Tritium is produced naturally in the upper atmosphere by interaction of nitrogen, and, to a lesser extent, oxygen with cosmic rays.

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