Stable isotope ratios in swale sequences of Lake Superior as indicators of climate and lake level fluctuations during the Late Holocene

摘要: Abstract Beach ridges along the coastline of Lake Superior provide a long-term and detailed record lake level fluctuations for past 4000 cal BP. Although climate change has been invoked to explain these fluctuations, its role is still in debate. Here, we reconstruct water balance by employing peat samples collected from swale deposits present between beach ridge sequences at two locations Superior. Carbon isotope ratios Sphagnum remains are used as proxy because presence or absence films on controls overall discrimination effects. Consequently, increased average content produces elevated δ13C values. Two maxima values interpreted reflect wetter conditions prevailed 3400 2400 cal BP about 1900 1400 cal BP. There relatively short drier periods inferred low values: one centered 2300 cal BP, begins A good covariance was found reconstructed lake-levels Michigan which carbon correlate well with higher levels. Based this covariance, conclude that exerts strong influence levels