PREHISTORIC MERCURY CONCENTRATIONS OBTAINED FROM TWO CONNECTICUT LAKES ALLOW FOR RECONSTRUCTION OF PAST VOLCANIC ACTIVITY

Lake sediment cores were extracted from two lakes in Connecticut using a modified Livingston corer; three long (9 and 12 m respectively) cores from Mudge Pond located in northwestern Connecticut (lat. 41°54’N, long. 73°28’W ) and one 11m long core from Lake Louise located in central Connecticut (lat. 41°51’N, 72°46’W). The goal of this study is to determine a regional record of mercury deposition through the Holocene in order to reconstruct past volcanic activity since a likely source of mercury deposition comes from volcanic emissions. Samples were taken every 2 cm from all three cores and dried at a low temperature (<40˚C) in an oven. Samples were ground by hand and homogenized. Subsamples, weighing between 3 and 10 mg, were analyzed in a DMA-80 Mercury Analyzer. Each sampling position within in the cores was measured a minimum of three times to account for sample heterogeneity. In both cores prehistoric mercury concentrations are low (5-40 ppb) compared to historic values (40-100 ppb), which are not part of this study. Preliminary analyses show a good correlation between the two cores taken from Mudge Pond, allowing us to obtain a local record of prehistoric mercury deposition for Connecticut, which can be interpreted in terms of volcanic activity in North America throughout the Holocene.