ANALYSIS OF CORE SEDIMENTS GATHERED FROM SLUICE POND (LYNN, MA) INDICATE POST-GLACIAL ENVIRONMENTAL CHANGES

Sediments at the bottom of lakes provide information about the local environmental changes over time. In urban watersheds these records can help to put recent anthropogenic influences into a larger context. Here, a study was performed on Sluice Pond (Tomlin's Pond) in Lynn, MA, to better understand environmental changes that have occurred in the pond's watershed over the Holocene. A piston core (SP07PC4) was taken from the pond in September 2007 (water depth 13.3 meters). Detailed core descriptions, magnetic susceptibility and loss on ignition tests were performed on the sediment core. Previous work in the area dates glacial retreat to be about 17.5-16.4 kyr BP (Ridge 2003). The bottom 2-3 cm of the core was grey sandy clay with small pebbles, likely representing a pro-glacial marine depositional environment. The upper 198.5 cm of the core varies in color from olive black to dusky yellowish brown to black. The texture of sediment in this upper section was mainly a very fine silty gyttja. Holocene gyttja shows variability in loss on ignition and magnetic susceptibility readings. The loss on ignition measurements show a few high values, with one low value at approximately 80 cm. The magnetic susceptibility data records the concentration of magnetic minerals in the sediments. A large spike in magnetic susceptibility is observed at 2 cm. The rapid increase in the magnetic susceptibility is likely due to human impacts associated with heavy residential development surrounding Sluice Pond. The sediment record from Sluice Pond shows promise for containing a preserved climate and environmental record for the Holocene.