RECONSTRUCTING PAST CLIMATE VARIABILITY AFTER THE LAURENTIDE ICE SHEET RETREAT IN NORTHERN NEW JERSEY USING A LAKE SEDIMENT CORE
These proxies reveal similar patterns of variability, whereby periods of larger-grained sediment input into the lake occur with higher TOC and TN values and vice versa, indicating that both proxies likely reflect changes in lake recharge. Higher values of TOC and a higher C:N ratio suggest the organic material came from land sources brought to the lake by flowing water thus reflecting lake recharge. Together, these data indicate that the Younger Dryas epoch (~12.8-11.5 kyr) was characterized by generally dry conditions, which culminated with a rapid transition to wet conditions during the early Holocene. This transition marked the wettest period of the last fifteen thousand years and occurs in parallel with peak summer insolation and high atmospheric CH4 values. Results of the ARM analyses reveal a strong coherence with the C:N ratios, with higher C:N values corresponding with lower ARM values and vice versa. Both records exhibit patterns that are coherent with local sea surface temperatures and Aug insolation (40o N), suggesting that shifts in the C:N and ARM values may reflect changes in the source of organic matter (e.g. algal versus vascular dominated) and/or other environmental factors related to climate.