The late-Holocene history of Gormire Lake (NE England) and its catchment: a multiproxy reconstruction of past human impact

Abstract

Sedimentary evidence spanning the last 3500 years from cores taken from the centre of Gormire Lake, Cleveland, northeast England, points to two periods of deforestation and catchment erosion. The first, mainly late Iron Age/Romano-British phase, began c. 200 BC and ended c. AD 600. The second began c. AD 1200, the time of early Monastic activity, and continued into the nineteenth century. The chronology for the core rests on 137Cs, 210Pb and 14C measurements and on the history of lead accumulation in the sediments. The majority of the AMS 14C dates are shown to be too old to varying degrees, depending on the source of the organic matter in the sediments. The record of vegetation change is derived from pollen analysis. Evidence for changes in sediment composition and source and for catchment erosion comes from magnetic measurements, element analyses using XRF, and organic biogeochemical analyses. There is a high degree of coherence between all these lines of evidence. Interpretation of the magnetic record is complicated as a result of the formation of biogenic magnetite by magnetotactic bacteria, especially during periods of minimal erosion, by the presence of the authigenic magnetic sulphide greigite and by probable magnetite dissolution. Despite these modifications to the magnetic mineral assemblage in the sediments, magnetic indications of catchment erosion are clearly distinguishable, especially in the record of the antiferromagnetic minerals haematite and goethite. Partial estimates of catchment erosion rates are presented, based on the evidence from the sediments from the deepest part of the lake.

The identification and biogeochemical interpretation of fossil magnetotactic bacteria

“…Magnetite magnetofossils, often partially oxidized to maghemite, have been found as a major magnetic component of lacustrine (Dearing et al, 1998;Kim et al, 2005;Oldfield et al, 2003;Pan et al, 2005;Peck and King, ;Snowball, 1994), microbial mat , hemipelagic (DinaresTurell et al, 2003;Housen and Moskowitz, 2006;Stolz et al, 1986), pelagic (Hesse, 1994;Hilgenfeldt, 2000;Lean and McCave, 1998;Petersen et al, 1986;Yamazaki and Ioka, 1997;Yamazaki et al, 1991) and carbonate platform (Maloof et al, 2007;McNeill, 1990;McNeill et al, 1988;Sakai and Jige, 2006) sediments. Greigite magnetofossils have not yet been identified in Quaternary sediments.…”

Multi-proxy studies in palaeolimnology

“…Wick et al 2003) are becoming increasingly important in multi-proxy palaeolimnological studies as the role of the lake's catchment and its vegetation and soils is so important in understanding lake biotic and sedimentary changes (e.g. Anderson et al 1995;Korsman and Segerström 1998;Seppä and Weckström 1999;Lotter 1999Lotter , 2001Bradshaw et al 2000Bradshaw et al , 2005aBradshaw 2001;Lotter and Birks 2003;Oldfield et al 2003b). Limnologists are exploring links between water chemistry and nutrient status and catchment vegetation (Maberly et al 2003;van Breemen and Wright 2004).…”

Main drivers affecting the Holocene sedimentary record – implications from small lake in Latvia

“…The declining trend in Ti profile is likely to have been caused by a decrease in the clay fraction (Boyle 2001). The coarsening in grain-size could possibly in- dicate a shift in the zone of accumulation area ; although the changes could also be caused by the enhanced erosion from the catchment (Oldfield et al 2003). After 2 000 cal.…”

“…The high concentrations of conservative elements (high Zr/Ti ratio), the presence of rock-forming elements (Ca, Mg; data not shown) and the high C/N ratio indicate a supply of coarser, poorly weathered soils from a recently deglaciated catchment (Engstrom, Wright 1984;Oldfield et al 2003;Panizzo et al 2008). After 11 200 cal.…”