Late Givetian Taghanic bioevents in New York State: New discoveries and questions

Recent study of late Middle Givetian deposits (upper Moscow Formation, Tully Formation, and lowermost Genesee Group) in east central New York State, has revealed new, more detailed information concerning the nature and timing of both the Taghanic transgression and the Taghanic bioevents in the type region of west central New York State. The present research focuses on foreland basin detrital facies, peripheral to the classic Tully Limestone succession in western New York; we have documented more complete and complex faunal facies successions essential for comparison to other regions. These new sections show that it is possible to extend bed by bed correlations of typical Tully marker units away from the carbonate platform into both basinal and nearshore detrital deposits, where sections are more complete. The resulting high resolution stratigraphic framework allows better assessment of the nature and timing of bioevents now recognized in the Taghanic interval in the New York and Pennsylvania region. This paper reviews Taghanic biofacies and focuses on reinterpretation of lower Tully deposits as outer shelf to basin facies rather than inner shelf or lagoonal facies as previously suggested. The potential relationship of the Tully Fauna to the post Taghanic Ithaca Fauna is discussed briefly. We also discuss these findings in the context of recent biostratigraphic and geophysical work by others within the Taghanic time slice, particularly, in Europe and Morocco.