Centennial-scale age offsets of plant wax n-alkanes in Adirondack lake sediments

Lacustrine sediments have the potential to preserve paleoenvironmental proxies such as terrestrial plant waxes at high temporal resolution. The fidelity of wax records, however, can be up several thousand years older than corresponding sediment, based on compound-specific radiocarbon (14C) analysis. Unfortunately, factors controlling 14C age offsets between and are not well understood. aims this study quantify compare n-alkane among lakes within same region, determine if drainage lake basin differences (e.g., size, relief, morphology, fluvial inputs) influence these offsets. We collected from five in Adirondack Mountains, NY, USA that lack petrogenic sources n-alkanes, range characteristics. Sediment models were constructed for each using a combination sediment 210Pb, 137Cs, macrofossil ages, compared ages long-chain (n-C27, n-C29, n-C31) alkanes sampled Holocene Late Glacial aged sediments. ageinitial is measure offset n-alkanes relative they deposited in. Across all lakes, ranged penecontemporaneous 2440 yr. This oldest significantly outside distribution other samples; when excluded, overall mean was 400 ± 255 yr (n = 23). largest values observed last 1 cal kyr BP (565 180 (1σ), n 12)) 13 (220 195 11)). These develop early after initial sedimentation follow similar pattern despite catchment geomorphology. speculate occur due reworking stored soils mechanism most effective ∼1 kyr. Regardless, temperate forested metamorphic bedrock terrains relatively small stable with extensive or anthropogenic disturbance. By targeting minimal soils, may reduced, thereby minimizing attenuation distortion climate signals isotopic records.