Reconstruction Holocene climate oscillations recorded in Lake Erie sediment: A multiproxy approach

Climate change influences physically, chemically and biologically to Lake systems and these changes are recorded in various ways in lake sediments. Understanding long term variability of climate change is crucial for better climatic predictions. Therefore, this study was carried out to understand the regional climate variability during the Holocene using multiple proxies on a sediment core from the central basin of Lake Erie.

A 1018 cm long piston core was used to identify climatic signals and this site mainly receives sediment from Detroit River fed by precipitation. Diffuse Spectral Reflectance (DSR), Particle Size Analysis, Magnetic Susceptibility (MS) were measured about 10 cm resolution. Varimax rotated Principal Component Analysis (VPCA) was performed for color reflectance data (DSR-VPCA) to extract major components that represent climate variability. Total Organic Matter (TOM) and XRF data was used to document regional climate changes during Holocene period. Previously published (Clotts et al., 2005) radiocarbon data based on microfossils was used to develop the age model.

The core represents climatic signals from 8.6 cal. kyr BP to 4.1 cal. kyr BP. Downcore variability data clearly indicates the 8.2 cold, dry climatic event and warm, wet period, began at about 8.6 cal. kyr BP, culminated at 8.1 cal. kyr BP and came to its end at about 7.3 cal. kyr BP. After that, the climate gradually become colder and drier until about 5.8 cal. kyr BP and again the wet-warm climate become dominant which represents the Holocene maximum period around 5.0 cal. kyr BP. Also, our records indicate that another short term climatic oscillation occurred at 4.2 cal. kyr BP which was a cold and drier event. However, our data fit other proxy records of regional climate change such as 8.2 cold event from early Holocene climate oscillations in Greenland ice cores. The main driving force for the climatic evolution in the Great Lakes region during the Holocene period is likely the solar insolation change and our data suggest that the Northern Hemisphere climate was less stable during the Holocene than previously thought.