Post-glacial climate change and its effect on a shallow dimictic lake in Nova Scotia, Canada

作者：Lennox Brent; Spooner Ian^*; Jull Timothy; Patterson William P

来源：Journal of Paleolimnology, 2010, 43(1): 15-27.

DOI：10.1007/s10933-009-9310-2

• Climate change
• Paleolimnology
• Nova Scotia
• Stable isotopes
• Multi-proxy
• Hydrogen index
• Limnology

A high-resolution, multi-proxy lake sediment record was used to establish the timing of Holocene environmental change in Canoran Lake, southwest Nova Scotia, Canada. Proxies include %C, delta(15)N, delta(13)C, HI, magnetic susceptibility, and pollen. Canoran Lake is a small, shallow (11 m) lake with two ephemeral inlets and an outlet. The site was deglaciated at ca. 15,300 cal (calibrated) year BP and elevated %C values indicate the establishment of a productive aquatic environment that is consistent with Allerod warming. The Allerod was interrupted by rapid air temperature cooling during the Younger Dryas (ca. 12,900-11,600 cal year BP). The Early Hypsithermal (ca. 11,600-8,500 cal year BP) was relatively warm and wet. A slight increase in clastic input occurred between 9,100 and 8,500 cal year BP but delta(15)N, delta(13)C, and HI values imply that the lithostratigraphic response may not be indicative of climate-induced change. The strong proxy response between 8,500 and 8,000 cal year BP was likely due to cooling and drying coincident with the 8.2 k year event. The climate was relatively warm and dry during the Late Hypsithermal (ca. 8,000-3,500 cal year BP). None of the proxies' exhibit notable change during the 5,500 cal year BP hemlock decline, indicating that ecological change was likely due to a pathogen attack. Post-Hypsithermal (modern) climate was characterized by an increase in precipitation and a decrease in air temperatures from ca. 3,500 to 700 cal year BP (top of core).

• 出版日期2010-1