Multi-proxy approach to long- and short-term Holocene climate-change: evidence from eastern Lake Ontario |
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Authors: | Melany?A?McFadden William?P?Patterson Email author" target="_blank">Henry?T?MullinsEmail author William?T?Anderson |
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Institution: | (1) Rosenstiel School of Marine and Atmospheric Sciences, University of Miami, 33149 Miami, FL, USA;(2) Department of Geological Sciences, University of Saskatchewan, 114 Science Place, S7N 5E2 Saskatoon, Sask., Canada;(3) Heroy Geology Laboratory, Department of Earth Sciences, Syracuse University, 13244 Syracuse, NY, USA;(4) Department of Earth Sciences and the Southeast Environmental Research Center, Florida International University, 11200 SW 8th Street, 33199 Miami, FL, USA |
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Abstract: | We use a multi-proxy (n = 11) paleolimnological approach on deep-water sediment from eastern Lake Ontario to characterize both long- and short-term regional climate change over the past ~10,000 calendar years. Proxies included % total organic matter, % total carbonate, magnetic susceptibility, C/N ratios, % organic carbon, % total nitrogen, % biogenic silica and 18O and 13C of carbonate, as well as 13C and 15N of bulk organic matter. There is a marked shift in most proxies at ~9.4 ka which defines the start of Holocene warmth in this region. Prior to this, the area was influenced by the post-Younger Dryas cold/wet interval, controlled by a southward displacement of the polar front jet stream, when many proxies were at their minimum. The Hypsithermal interval (~9.4–5.3 ka) was the warmest and wettest of the Holocene due to a long-term increase in summer insolation. The Hypsithermal, however, was interrupted by two cold climates; the 8.2 ka event (~8.4–8.0 ka) and the Nipissing Rise (~6.8–5.0 ka), both of which are linked to a reduction in thermohaline circulation and northward oceanic heat transport. The Neoglacial interval (~5.3 ka to ~1850 AD), driven by a long-term decrease in summer insolation, was cooler and dryer, but more stable, than the Hypsithermal. The short Historic interval (post ~1850 AD) was characterized by some of the largest amplitude and most abrupt anomalies of the past 10,000 years, due to intense anthropogenic activity, when a number of proxies reached unprecedented values. |
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Keywords: | Climate change Holocene Lake Ontario Multi-proxy Stable isotopes |
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