The record of atmospheric deposition on a rainwater-dependent peatland

Abstract

Rainwater-dependent peatlands retain a record of atmospheric deposition. Unlike lake sediments they record both particulate and soluble influxes, and they are not complicated by processes in the catchment or by mineral particle influx from the catchment. They do, however, have their own difficulties some of which are considered here. The timescale for cores from a suitable peatland in Southwest Scotland was established by a combination of 14 C ‘wiggle matching’, pollen events, 210 Pb dating and the 241 Am event. Retention of deposited elements varied greatly from less than 1% (Na) to complete retention (N). Hummocks retained more than hollows: the quotient was 1.2-1.8 for elements such as A1 (associated with particles) and up to 5-10 for Mn, Fe and Zn. The vertical scale in profiles should be as cumulative dry mass or, better, as dry mass after reconstructing losses by decay. These give vertical scales that are approximately linear with age. Elements differ greatly in the shape of their concentration profile as a result of varying influx and as a result of relocation in the peat.