What was done
The authors analyzed the varve thickness and continuous gray-scale density of sediment cores taken from Elk Lake, MN (47°12'N, 95°15'W) for the past 1500 years.

What was learned
Significant periodicities were noted throughout the record, including multidecadal periodicities of approximately 10, 29, 32, 42 and 96 years, and a strong multicentennial periodicity of about 400 years.

What it means
The authors openly question whether or not the observed periodicities are manifestations of solar-induced climate signals and present strong correlative evidence that they are.  The 10-year oscillation was found to be strongest in the time series between the 14th and 19th centuries, during the Little Ice Age, and may well have been driven by the 11-year sunspot cycle.