SEDIMENTARY HISTORY OF QUEENS LAKE, WILLIAMSBURG, VIRGINIA: CONNECTING LACUSTRINE AND ESTUARINE SYSTEMS WITHIN THE VIRGINIA COASTAL PLAIN

Queens Lake is a small, ~0.25km² manmade lake that drains into the adjacent Queen Creek, located within the Coastal Plain Province of eastern Virginia. The lake was formed c. 1920 from the damming of a tributary to the estuarine Queen Creek, an incised valley in the southern Chesapeake Bay created during Pleistocene regressions and filled by marsh sediments during subsequent Holocene transgressions. The lake’s 3.9km² watershed has hosted a variety of human impacts over the past 400 years, starting with the development of the historic City of Williamsburg, early 20^th century expansion of an adjacent neighborhood and more recently a section of an interstate highway.

Two ~80cm piston cores were extracted from the lake and analyzed for grain size, magnetic susceptibility, bulk density, organic matter content, organic carbon, nitrogen and sulfur. An age model was established using ¹³⁷Cs and ²¹⁰Pb isotopes. The transition from estuarine to lacustrine sedimentation began in 1920 (with dam construction) at core depths of ~20cm, marked by a significant increase in sand, decrease in organic matter, increase in %C, and decrease in %S. Post-dam sedimentation is characterized by several pulses in sand-sized sediment, with an overall increase in silt and organic content, steadily increasing %C, and attenuating C/N ratios up-core. In closer detail, a spike in %C ~1950 signifies an increase in terrestrial organic matter input, likely derived from land clearing associated with initial development of the surrounding neighborhood. The gradual decrease in C/N ratios, and increasing %C post-1980 likely reflects an increase in lake eutrophication. Overall sedimentation rates average ~0.25 cm/yr, consistent with work on other nearby lakes.

The sedimentary history of the lake helps to better understand the extent and timing of human impacts within small-scale lacustrine systems similar to those throughout the Coastal Plain. This work also contributes to ongoing studies of sedimentation in the adjoining Queen Creek where sedimentation is complex and dynamic and these data help resolve a more accurate estimate of land-derived input into the estuarine system.