The assessment of chemical weathering rates within an upland catchment in north‐east Scotland

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Abstract
A study has been made of weathering in Glendye, an upland catchement of heather moorland underlain mainly by granite with some gneiss in north‐east Scotland. The concentrations of a range of elements and ions in precipitation and river water were measured over a twelve‐month period. The total input and output of each element or ion was calculated. The resulting balances show net outputs of all species except hydrogen ion. Large net outputs of silicon (38.5 kg ha−1 a−1) and bicarbonate (48 kg ha−1 a−1) indicate considerable chemical weathering. A large net output of chloride (32 kg ha−1 a−1) indicates the importance of dry deposition of oceanic aerosols. When this is allowed for the rate of output of elements due to weathering is.Si>Ca>Na>Mg>K>Fe>Al.These results were compared with the abundance of elements in bedrock and differential weathering ratios calculated. These are compared with data from the Hubbard Brook study in New Hampshire. In both cases calcium is by far the most mobile element. The relative importance of the atmosphere and of chemical weathering as sources of each element was calculated, and the results compared with those of a study at Wet Sleddale in the Lake District. Similar patterns emerge in both cases.