Field research in paleoclimatology and coastal geology

whoi

The feasibility of determining paleowind orientation from erosional deposits within kettle ponds of New England

Researcher: P. Zion  Klos – WHOI Summer Student Fellow, Colorado College Geology Major

Advisor: Jeff Donnelly – Coastal Systems Group, Department of Geology and Geophysics, WHOI

Abstract

This study tested the feasibility of using asymmetry in shoreline erosion, and associated basin deposition, in kettle ponds to determine paleowind orientations on a temporal scale.  Ground penetrating radar (GPR) and core samples were used to determine the orientation of asymmetry in pond deposits.  The study focused primarily on asymmetry in sediment characteristics occurring within the ~8200-8400 y.b.p. layer associated with a drastic climate change caused by the abrupt slowing or stopping of the North Atlantic thermohaline circulation. This event may be a proxy for the near future as rapid melting of the Greenland ice sheet increases the influx of freshwater to the North Atlantic.   Additionally, this study is also a reconnaissance survey of ponds in southeastern Massachusetts using GPR. The secondary goal is to locate additional sites containing a simple vertical stratification of compositionally variable sediment packages who’s characteristics are temporally linked to climate conditions, such as past storm events, drought, fire, vegetative changes, and groundwater rise.  Results indicated two ponds within southeastern Massachusetts suitable for paleowind determination from depositional asymmetry.  Detailed GPR transects and coring indicated an orientation of strong paleowinds from the southwestern direction during the 8200 y.p.b. event which contrasts with current day storm events creating strong winds in northeasterly and southerly directions.   Being the first study of its kind, further research is needed to prove the definite validity of this method for determining paleowind orientation from asymmetry in lacustrine deposits.

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