HOLOCENE PALYNOLOGY AND S E DI M E NT O LO G Y 



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Pollen concentration 

 qrains/g dry wt. 



X 1000 

 10 20 30 40 50 



Per cent 



total 



20 30 40 50 

 X 1000 



Core collected at 42° 14.05' N., 86° 39. 2' W. from 49.9 meters of water. 



detrital carbon being deposited in the sediment is constant relative to the percent- 

 age of indigenous carbon, these dates can be used to plot sedimentation rate curves 

 The fact that the radiocarbon dates shown in figure 9 plot in a straight line indi- 

 cates that the dates are useful for determining sedimentation rates, but not neces- 

 sarily for determining absolute age. 



Cyclic variations in the declination of the geomagnetic field have been 

 discovered in the Lake Michigan sediments (Creer, Gross, and Lineback, 1976). 



