Date of Award

2003

Level of Access Assigned by Author

Open-Access Thesis

Degree Name

Master of Science (MS)

Department

Quaternary and Climate Studies

Advisor

George L. Jacobson

Second Committee Member

Daniel F. Belknap

Third Committee Member

Ann C. Dieffenbacher-Krall

Abstract

This study of late-glacial and Holocene changes in lake-level and vegetation at Mathews Pond contributes new information about Holocene environments in northeastern North America. The research establishes a 12,000-year record of paleohydrology for the watershed adjacent to Big Reed Forest Reserve, the largest stand of old-growth forest in the northeastern United States. Mathews Pond is a 7.4 ha, closed-basin, groundwaterseepage lake located in an upland, forested region of the Aroostook River drainage system. Glacial meltwater briefly filled the basin - 13.0 ka (1 ka = 1000 I4C yr BP)). The lake existed as a shallow pool in the deep area of the basin between 11.0 and 9.4 ka. Water levels rose to near-modern levels by 8.4 ka, and, except for a slight decline around 7.5 ka (8200 cal yr BP), remained high until 4.8 ka, when a distinct low-stand lasted until 3.0 ka. After 3.0 ka the lake level rose to the modern level with intermittent low and high fluctuations of 200-500 year duration. Synchrony of lake-level changes between Mathews Pond and Whited Lake, a groundwater seepage lake in an adjacent watershed, and from additional sites across northeastern North America provides strong evidence that Holocene climate varied with 1500-2000 year periodicity and with sufficient intensity to alter regional moisture balance. Synchrony of groundwater response between watersheds and across broad geographic regions suggests that changes in moisture balance are driven by external influences such as solar insolation or shifts in atmospheric circulation. Integration of lake-level, charcoal, and pollen data at centennial-scale temporal resolution identified subtle increases in groundwater recharge in response to decreased forest transpiration following local forest fires.

Comments

As of 2002, Degree of Master of Science (MS) Quaternary and Climate Studies published under the auspices of the Climate Change Institute.

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