AN EXCEPTIONAL HIGH-RESOLUTIUON STABLE ISOTOPE RECORD OF THE LAST DEGLACIATION FROM NW NEW JERSEY

A detailed history of climatic changes from the Late Pleistocene to recent is recorded in a high-resolution stable isotope record from lake sediments of Northwestern New Jersey. The transition from the Last Glacial Maximum (LGM) into the present interglacial is characterized by relatively large and rapid climate fluctuations that are recorded in the d¹⁸O values of sedimentary carbonate from this site. Given that the position of Glovers Pond was very close to the Laurentide ice sheet margin during the last glacial maximum, the basin has recorded sedimentation for over 20,000 years. An excellent correlation exists between the d¹⁸O values from Glovers Pond and the Greenland ice core records showing evidence of major climatic events that include the Bølling-Allerød, the intra-Allerød cold period, the Younger Dryas, the Preboreal Oscillation and the early-Holocene 8200 cal BP cold event. The carbonates within the lake are predominately produced by the green alga Chara sp., whose isotope values are consistent with the calculated equilibrium d¹³C and d¹⁸O values for the ambient water. The lake margin core records a ~2‰ decrease in carbonate d¹⁸O values (from –6 to –8‰) during the Younger Dryas time, which is likely due to more humid and cooler conditions that introduced meteoric water with lower d¹⁸O values into the lake. The Holocene warming following the Younger Dryas is interrupted by several brief reversals that are evident within the lake sediments including the Preboreal and the 8200 cal BP event which both show a ~1.5‰ decrease or better. The high-resolution sampling technique applied to this study has proved to be extremely valuable in capturing climatic events that are generally missed or possibly misinterpreted. More importantly the data collected are significant in linking the terrestrial record to regional and global climate changes during deglaciation.