Description
- Abstract:
- Past hydroclimatic change is shown from the reconstruction of paleo-lake levels from New Long and Rocky Ponds in southeastern Massachusetts, and Davis Pond in western Massachusetts show evidence for multiple, sub-centennial-to-millennial scale lowstands during the transition from the late-Pleistocene (15.0 ka) through the Holocene (0.0 ka), and for repeated sub-millennial scale, spatially coherent, lake level changes from 8.0 - 0.0 ka. Sedimentary evidence from New Long Pond indicates a drop in water levels in the mid AD 20th century, when instrumental data show lower-than-average precipitation in the northeastern United States, and a prolonged low water stand during the Medieval Climate Anomaly like that in the American southwest, which also overlaps a 100-yr interval of warm tropical Atlantic sea surface temperatures and cool La Niña-like Pacific conditions. Ground penetrating radar and sediment core data from the basins indicate numerous paleo-shoreline deposits from 15.0-7.0 ka. Davis and New Long Ponds also reveal past droughts during the Holocene. Many of the late-Pleistocene/early Holocene low lake levels coincide with proposed meltwater release events or abrupt climate oscillations in the North Atlantic region, with at least three low stands during the Younger Dryas, and in association with the "9.2" and "8.2" ka events. Although the effect of summer insolation after 8.0 ka may be instrumental in a sequence of droughts from 6.2-4.8 ka, the ca. 6.0 ka and 3.1-2.7 ka droughts also coincide with reduced meridional overturning circulation in the North Atlantic region. The combined evidence of concurrent paleo-droughts in southeastern New England with documented North Atlantic abrupt cooling events, and recent drought with the modern association of low sea-surface temperatures, indicates that freshening and cooling of the western North Atlantic is a viable mechanism for decreasing moisture within the region. Large-scale changes in seasonality and ice sheet extent also may have increased the susceptibility of the northeast to dry conditions triggered by changes in the North Atlantic.
- Notes:
- Thesis (Ph.D. -- Brown University (2010)
Access Conditions
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- In Copyright
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Citation
Newby, Paige E.,
"Evidence of late Pleistocene and Holocene Centennial-Scale Drought from Southeastern Massachusetts"
(2010).
Earth, Environmental and Planetary Sciences Theses and Dissertations.
Brown Digital Repository. Brown University Library.
https://doi.org/10.7301/Z0VD6WPZ
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Earth, Environmental and Planetary Sciences Theses and Dissertations
Theses and Dissertations for the Earth, Environmental and Planetary Sciences department....