41 Paleontology, Stratigraphy, Sediments, and Soils (Posters)

Wednesday, 11 March 2026
9:00 AM - 12:00 PM
RCC, Lower Level Hall

Initial insights on Metropolis Lake, a potential limnogeological archive of recent environmental change in western Kentucky

Paper number: 41-6
Program: Technical Sessions
Time: 10:30 AM – 10:45 AM

Authors

Abstract

Located on the Ohio River floodplain in western McCracken County is one of the few natural lake basins in Kentucky: Metropolis Lake. Metropolis Lake lies within Metropolis Lake State Nature Preserve, dedicated in 1984 to protect water resources, a stand of bald cypress and swamp tupelo along the lakeshore, and several rare fish species (e.g., cypress minnow, red-spotted sunfish, and taillight shiner). In the early 20th century, Metropolis Lake was a popular recreational area, but in 1951 the Tennessee Valley Authority began construction of the Shawnee Fossil Plant. This development, along with nuclear development in nearby West Paducah, transformed the area. The available details on the limnogeology of Metropolis Lake are very few. Our initial investigation of Metropolis Lake shows that the northwest-southeast oriented lake basin covers ~0.15 km2 and connects to the Ohio River via an artificial channel at the northwest corner. The lake sits in Quaternary alluvium, and the minor topography adjacent to the south and west of the lake is made up of Quaternary loess. The lake is ~400 m from the Ohio River channel and is subject to flood pulses from the river. The influence of groundwater on Metropolis Lake is not fully understood and is the subject of ongoing investigation by our team, but thermal camera measurements indicate that groundwater springs are present at several locations on the lakeshore. Preliminary water measurements suggest that the total dissolved solids are low (field conductivity of 103 µS/cm), the chemistry is dominantly a HCO3−, Ca2+, Cl− hydrochemical type, and the pH is ~9.2. The water column is shallow (~0.3 to 1.3 m deep) and well-mixed. Lake floor samples (n = 44) are consistent with the shallow lacustrine environment of deposition: sediments are massive dark green to gray muds with varying amounts of sand, organic debris, and charcoal. Mollusk shells were rarely encountered in Metropolis Lake sediments, whereas diatoms and sponge spicules were common. The total thickness of lacustrine sediment is not yet known for Metropolis Lake, but future sediment coring and geophysics will seek to reveal ecological and environmental changes archived in the lake sediments.  

Geological Society of America Abstracts with Programs. Vol. 58, No. 1

doi: 10.1130/abs/2026SE-411604

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