University of New Hampshire University of New Hampshire Scholars' Repository New England Intercollegiate Geological NEIGC Trips Excursion Conference Collection 1-1-1969 Utica and Canajoharie Shales in the Mohawk Valley Riva, John Follow this and additional works at: https://scholars.unh.edu/neigc_trips Recommended Citation Riva, John, "Utica and Canajoharie Shales in the Mohawk Valley" (1969). NEIGC Trips. 122. https://scholars.unh.edu/neigc_trips/122 This Text is brought to you for free and open access by the New England Intercollegiate Geological Excursion Conference Collection at University of New Hampshire Scholars' Repository. It has been accepted for inclusion in NEIGC Trips by an authorized administrator of University of New Hampshire Scholars' Repository. For more information, please contact
[email protected]. Utica and Canajoharie Shales in the Mohawk Valley Leader: John Riva INTRODUCTION In Middle Ordovician time carbonate deposition in the Appalachian miogec syncline, from Pennsylvania to the island of Anticosti in the Gulf of St. Lawrence, was gradually replaced by an influx of black shale commonly referred to as the "Utica” shale. The "Utica” entered the miogeosyncline from the east or south east and progressively moved westward attaining the cratonal margins in Ontario (Manitoulin Island) and well overlapping the Precambrian Shield (Lake St. John area in Quebec) in late mid-Ordovician time. This black shale invasion was followed by coarse clastic sediments, first represented by the Schenectady beds in the lower Mohawk valley, northwestern New York, and parts of Ontario and Quebec. The "Utica" consists essentially of grey-black shale and thin limestone interbeds; lithologically, shales in the upper Mohawk valley are indistinguishable from those, much older, in the lower Mohawk.