THE SEDIMENTARY ARCHIVE OF LAKE WABAN- MULTIPROXY ANALYSIS OF LAND USE CHANGES SINCE THE PRE INDUSTRIAL ERA

Lake Waban is a kettle lake situated in eastern Massachusetts. It formed at the end of the Last Glacial Maximum. Waban has a surface area of 44 hectares. It is a stratified, slightly eutrophic lake with maximum depths of 13 and 12 meters in the two sub-basins and a mean depth of three meters. The main tributary, the Waban Brook, flows out of Paint Shop Pond to the northwest. In recent history, the Lake Waban watershed region has been home to both business and industry. Since the 1600s, mills populated the area surrounding Upper Waban Brook. The nearby Boston to Worcester Railroad was built in 1835. From 1848-1928 a paint shop situated on the shores of Waban’s main upstream tributary was in production.

The purpose of this study is to identify changes in the lake environment over time using sediment gravity cores taken from the two deepest basins of Lake Waban. Based on interpretation of an earlier seismic survey, four sediment cores up to 55 cm length were collected and analyzed sedimentologically. We measured magnetic susceptibility and dry bulk density at intervals of 2 cm, and we analyzed grain size with laser diffraction. We took smear slides at selected horizons to analyze the lake sediment components and determine the amounts of authigenic, biogenic, and clastic materials. The sediment is mostly composed of organic rich mud. Sediment cores show higher magnetic susceptibility above 28 cm core depth in each core that can be interpreted as the effect of industrialization in the area. A potential mass wasting deposit with plant debris was identified in core WAB-18-GC3 at 35-40 cm depths, which could be an indication of a storm event. Grain size data shows a multimodal distribution with the main mode around 100 microns which is representative of diatom frustules. Further sediment analysis and better age control will allow us to reconstruct the landscape history in more detail.