A MULTI-PROXY ANALYSIS OF SEDIMENT CORES FROM CHAIN OF PONDS, MAINE

Lake sediments are a principal archive of environmental changes both locally and regionally. Chain of Ponds, Maine consists of five lakes that that are oriented northwest to southeast following a Quaternary drainage route and an inactive fault line. Sediment cores were taken from Round Pond, Natanis Pond, Long Pond and Bag Pond (from north to south) in order to reconstruct environmental conditions of the area during the Holocene. Each pond has one or more uncharacteristically deep holes, and sediment cores were retrieved from a total of five basins from the four ponds. Four cores are Kullenberg cores varying in length between 145cm to 205cm. An additional Livingstone core, with a length of 72cm, was taken from Round Pound due to accessibility issues. A multi-proxy analysis was performed on the cores, including physical stratigraphy, magnetic susceptibility and loss on ignition (organic carbon). All five cores have similar lithologies: dark massive gyttja with occasional sandy layers. Two of the cores (Natanis Pond and Bag Pond) have distinct sandy layers with terrigenous macrofossils, the top of which occurs at 10-15 cm down-core. Natanis Pond shows a magnetic susceptibility peak at this layer, with values reaching 57 SI units, while Bag pond shows relatively low values for this section, only reaching as high as -1 SI units. These layers seem to correlate between the two basins suggesting a common cause. Potential events that might have produced these are the construction of a dam in 1928, an extreme climate event or land use changes. Four out of the five cores show a clear increase in magnetic susceptibility between 20-30 cm down-core, which is likely due to anthropogenic influence. This increase is likely be correlated with the onset of the Industrial Revolution and, in turn, suggests a sediment rate of ~0.15cm per year in the upper section of the cores.