Analysis of sediment reveals an ecological regime change in Lake Hilary

Lake sediments contain excellent records of both fossils and component minerals that can be used to reconstruct regional ecological history. To complement ongoing studies of Lake Hilary’s pollen and macrofossils, we constructed a high-resolution record of the organic matter, carbonate, and non-carbonate mineral fractions of the lake’s sediment. The organic fraction is a proxy for the biological productivity of the pelagic, littoral, and shoreline of the lake. Non-carbonate minerals can evince erosion and subsequent aerial or fluvial deposition. Carbonate deposition can be related to lake productivity and chemical weathering in the surrounding watershed. We sought to compare our sediment record to existing records for pollen and charcoal from Lake Hilary and find evidence for linkages between vegetation change and sediment composition