Relative ages of Late Pleistocene moraines and rock glaciers were evaluated.
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A progressive increase in mean R-values from valley outlets to cirques was observed.
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The high dating potential of the Schmidt hammer for older rock surfaces is shown.
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Weathering indexes indicate relative age categories for deglaciation stages.
Abstract
In order to evaluate the potential of the Schmidt hammer for relative age dating of Late Pleistocene moraines and rock glaciers, rebound (R) values were collected at 38 sites in two formerly glaciated valleys in the Western Tatras in northern Slovakia. A large statistical population of measurements obtained from moraine and rock glacier surfaces was used to analyze the variability of mean R-values in the same lithology and overall southern valley exposition. Four separate sets of glacial/periglacial morphosystems are present at different positions in the Western Tatras starting from valley outlets to the highest cirques, which represent successive phases of deglaciation. R-value means and 95% confidence intervals for selected Last Glacial Maximum (LGM), and Late Glacial (LG-1, LG-2 and LG-3) stages (respectively, 40.1 ± 1.1, 46 ± 0.5, 53.5 ± 1.0 and 60.5 ± 0.3) are significantly statistically different and values for each age category are comparable for the two analyzed valleys. The results of weathering indexes used in conjunction with geomorphological relationships were taken together to reconstruct the pattern of deglaciation on southern Tatra slopes. It is stated that the Schmidt hammer technique may be successfully used as a relative age dating tool for Late Pleistocene glacial and periglacial deposits, and with this method, it is possible to differentiate between Late Glacial moraines and rock glacier systems of different age.
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