Advances in Understanding Late Pleistocene Event-Stratigraphy in Central New York: From Application to Paleoclimate Correlation
Understanding late Pleistocene stratigraphy has long been recognized as crucial for applied geological applications such as contaminant hydrogeology, ground water modeling, planning municipal water supplies and aggregate resource extraction. In some locations of the glaciated Great Lakes, stratigraphic investigations by state geological surveys and academia have made enough progress to establish organized time-stratigraphic nomenclature to the formation and member level, similar to long established practices for bedrock stratigraphy. However, the inequity of resources from state to state has often resulted in localized state specific lexicons and provincial correlations of Pleistocene stratigraphy that often stop at state political boundaries. Further, in many cases a lack of modern subsurface investigations specifically targeting detailed data collection of the stratigraphic framework and chronologic information has fostered the continued use of primitive and sometimes outdated concepts for time-stratigraphic relationships. A further disconnect is that established regional stratigraphic models based on decades of terrestrial geologic investigations in the Great Lakes often do not integrate with the Pleistocene timestratigraphic frameworks recognized from deep sea cores and ice cores from Greenland. The marine isotope stage (MIS) records from sea and ice cores reveal a climatically coupled event stratigraphy an order of magnitude greater in detail than most published domestic time- stratigraphic models. In New York State, a lack of detailed data has led previous researchers to believe or adopt a simplified philosophy that each glacial advance fully eradicates any record of previous glacial or non-glacial stratigraphy. More commonly glacial deposits are lumped together as a singular lithostratigraphic unit typically described simply as drift. However, new detailed stratigraphic investigations at both the outcrop level and in the subsurface, in central New York by the State Museum-Geological Survey are providing data to establish formation and member level stratigraphy. The new data serves to bracket late Pleistocene events, and simultaneously correlate them to the event stratigraphy observed in the Greenland ice cores. The improved stratigraphic resolution and event stratigraphy pro vides a context to better understand the distribution and extent of former ice sheets in central New York and by association, the paleoclimate.