Multiproxy surface wetness records from replicate cores on an ombrotrophicmire: implications for Holocene palaeoclimate records

Ombrotrophic mires can provide records of palaeoclimate over the mid- to la te-Holocene in several areas of the world. Their potential is currently par tly limited by difficulties with scaling indices based on plant macrofossil s and humification, and the need to account for the internal variability of the mire system. This paper explores the use of testate amoebae analysis a s a third technique and assesses the minimum within-site variability by com paring results from two closely spaced cores. Reconstruction of surface wet ness changes was carried out on cores from the centre of an intermediate ra ised-blanket mire, Coom Rigg Moss, Northumberland, by analysis of restate a moebae, plant macrofossils and humification. Surface wetness changes were e xpressed as mean annual water table changes inferred from testate amoebae a ssemblages, two separate indices based on plant macrofossils and percentage transmission of humification extracts. Comparisons between the proxies sug gest good agreement of general trends in Sphagnum peats but some difference s in monocot and ericaceous peats. The magnitude of surface wetness changes also differs within Sphagnum peats. The records from the separate cores co nverge over time and replicability between cores is best in the last 7000 y r. Changes over this period are similar to those shown by estimates based o n documentary sources. Good agreement is obtained between a normalised plan t macrofossil index and normalised reconstructed water-table values and it is suggested that this approach could form the basis for improved composite , multiproxy records from peatlands. Copyright (C) 1999 John Wiley & Sons, Ltd.