Sediment records from closed-basin lakes in the Northern Great Plains (NGP) of North America have contributed significantly to our understanding of regional paleoclimatology. A high-resolution (near decadal) fossil diatom record from Kettle Lake, ND, USA that spans the last 8500 cal. yr BP is interpreted in concert with percent abundance of aragonite in the sediment as an independent proxy of groundwater flow to the lake (and thus lake water level). Kettle Lake has been relatively fresh for the majority of the Holocene, likely because of the coarse substrata and a strong connection to the underlying aquifer. Interpretation of diatom assemblages in four groups indicative of low to high groundwater flow, based on the percent of aragonite in sediments, allow interpretations of arid periods (and probable meromictic lake conditions) that could not be detected based on diatom-based salinity reconstructions alone. At the centennial-millennial scale, the diatom record suggests humid/wet periods from 8351 to 8088, 4364 to 1406 and 872 to 620 cal. yr BP, with more arid periods intervening. During the last ~ 4500 years, decadal-centennial scale periods of drought have taken place, despite the generally wetter climate. These droughts appear to have had similar impacts on the Kettle Lake hydrology as the 'Dust Bowl' era droughts, but were longer in duration.
Bibliographical noteFunding Information:
We would like to thank George L. Jacobson Jr, James S. Clark, Wayne Lusardi, and Bryan Shuman who successfully retrieved the core. Pietra G. Mueller sieved the sediments for macrofossils and charcoal and prepared specimens for AMS radiocarbon dating. Statistical advice was given by Steve Juggins. This work was funded by National Science Foundation grants to S.C. Fritz (EAR06-02154), E.C. Grimm (ATM-0213246), and J.J. Donovan (ATM-0214108).
Copyright 2012 Elsevier B.V., All rights reserved.
- closed-basin lake
- groundwater flow
- Northern Great Plains