Pool-and-Hummock Patterning in a Southern Pennine Blanket Mire I. Stratigraphic Profiles for the Last 2800 Years

Abstract

1 This investigation uses detailed stratigraphic studies across an uneroded area of hummock-and-hollow blanket mire adjacent to well-developed erosion gullies in the Southern Pennines to examine the formation of surface patterning and of reticulate (Type 1) gully systems. 2 The stratigraphic profile of a 15-m section encompassing three hummocks, three hollows and an erosion gully is reconstructed from macrofossil and pollen analyses of twenty peat cores along the section. 3 Contemporaneous levels in the profile are established from the pollen analyses, and dated by reference to radiocarbon assays of 12 peat samples spanning a time interval from 430 to 2695 years BP. Major increases or decreases in Plantago pollen occur at C. 100 BC, AD 350 and AD 11 50 (based on calibrated radiocarbon dates). 4 Periodic concentrations of carbonized plant material in the macrofossil analyses are shown to relate to a series of at least 15 laterally continuous burning horizons in the stratigraphic profile. Burning horizons at c. AD 1250, 1000 and 150, and 230, 380 and 860 BC (based on calibrated radiocarbon dates) are used in conjunction with the Plantago pollen horizons to reconstruct the changing configurations of the mire surface along the study transect over the last 2800 years. 5 The reconstruction shows that microtopographic differentiation of the mire surface on Alport Moor into pools, hollows and hummocks resulted from differential rates of peat accumulation locally within a rather featureless vegetation cover that had developed by about 2200 years ago. Areas of retarded peat accumulation developed gradually into hollows and pools over a time-period of more than 1000 years. There is no evidence for the existence of a regeneration cycle of peat accumulation in the profiles.