Holocene climate trend, variability, and shift documented by lacustrine stable-isotope record in the northeastern United States

Earlier studies indicated that the general pattern of the Holocene climate in the northeastern United States changed from cool and dry (11.6–8.2 ka; 1 ka = 1000 cal yr BP) to warm and wet (8.2–5.4 ka) to warm and dry (5.4–3 ka) to cool and wet (after 3 ka). A new ∼35-year resolution stable isotope r...

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Bibliographic Details
Published in:Quaternary science reviews 2010-07, Vol.29 (15), p.1831-1843
Main Authors: Zhao, Cheng, Yu, Zicheng, Ito, Emi, Zhao, Yan
Format: Article
Language:English
Subjects:
Freshwater
Marine
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Summary:Earlier studies indicated that the general pattern of the Holocene climate in the northeastern United States changed from cool and dry (11.6–8.2 ka; 1 ka = 1000 cal yr BP) to warm and wet (8.2–5.4 ka) to warm and dry (5.4–3 ka) to cool and wet (after 3 ka). A new ∼35-year resolution stable isotope record of endogenic calcite from a sediment core for Lake Grinnell in northern New Jersey provided a chance to examine the Holocene climate variations of the region in a finer detail. After the Younger Dryas cold climate reversal, the δ 18O fluctuated around a constant value of −7.4‰ until 5.8 ka, thereafter shifted to a steadily decreasing trend to the most recent value of −8.2‰. Responding to this shift, the widely observed hemlock decline in the northeastern USA occurred about ∼350–500 (±143.5) years later. Detrended δ 18O and δ 13C records show a clear covariance at 910-year periodicity. The amplitudes of centennial-scale δ 18O variations became much smaller after 4.7 ka. At the same time, the dominant frequency of these variations changed from 330 to 500 years. We suggest that a non-linear response of atmospheric circulation to the gradual decrease in insolation is responsible for the shift in the climate trend at 5.8 ka as indicated by the deceasing δ 18O values. A dominant frequency shift in solar forcing and the decreased seasonal contrast of insolation might have caused the change in climate variability at 4.7 ka through modulating ocean and atmosphere circulations.
ISSN:0277-3791
1873-457X
DOI:10.1016/j.quascirev.2010.03.018