CENTRAL NEW YORK VARVE CHRONOLOGY: A SUGGESTION FOR QUATERNARY GEOLOGISTS

Work done to build a chronology of deglaciation using varves has been the focus of a number of researchers in New England for many years. The locations employed to build their timeline have been quite useful to date. However, New England is not the only place in the Northeast conducive to studying the last deglaciation of North America. The discovery of a set of ice proximal varves in an ancient glacial lake, now a swamp, in Oswego County, central New York, has shown that some locations outside of New England would be suitable for similar studies. The land having been shaped and sculpted by glacial outwash and sediment deposits, Oswego County provides an excellent insight into the deposition processes of small glacial lakes, now swamps, with varve records. Supporting the suggestion of a new location for study are the patterns that exist within the varve sequences in Oswego County.

Research done by a collaboration of geoscientists have observed the presence of El Niño period length signals within the Fourier transform of the continuous New England Varve Chronology project’s data set of varve thicknesses. The signals therein represent oscillations in climatic control over the deposition of varves (i.e. controlling thickness of varve). Varve sequences taken from the Oswego County swamp also exhibit the presence of these signals when subjected to Fourier analysis. Despite having only a fraction of the amount of varves as the NEVC project, similar frequency signals are present within all cores taken from the Oswego County swamp. This is interpreted as both locations being controlled by similar oscillations in climatic factors. It also suggests that although the varves found in central New York may not be directly correlated to the NEVC project, more than one database of varve chronology would be helpful and most likely necessary to adequately recount the timing and nature of deglaciation in North America. The use of MATlab codes were implemented in order to conduct the Fourier analyses. Further, this project sought to show that cores produced by methods of vibracoring do not skew the data or the patterns that emerge. This project was foremost undertaken to present more evidence that central New York is a worthwhile and warranted place for further study of the timing and nature of the last deglaciation to occur in the Northeast.