Niagra Falls, New York
SEDIMENTS OF NEW YORK STATE
The state's sedimentary rocks were largely deposited in relatively shallow "epicontinental" ("upon" the "continent") seas and adjacent continental environments during the geologic past. Most of these rocks were deposited during a 160 million year interval in the early to middle parts of the Paleozoic Era from approximately 520 to 360 million years ago. This interval of time spans four geologic periods, the Cambrian, Ordovician, Silurian, and Devonian (from oldest to youngest). New York also features thin and locally-occurring rocks of the late Paleozoic Era (Mississippian and Pennsylvanian subperiods of the Carboniferous Period) in Alleghany State Park and the Mesozoic Era (Triassic, Jurassic, and Cretaceous periods) on Long Island and the Nyack-Ramapo area of the southern Hudson valley.
Many of New York's famous and unique topographic features are directly related to the type of sedimentary and metamorphosed sedimentary rocks that underlie an area. Tourist sites such as Kaaterskill and Niagara falls, Ithaca's gorges, Ausable Chasm near Lake Champlain, Howe and Secret Caverns, Salamanca's Rock City, and Saratoga's Petrified Gardens are all defined by underlying bedrock. Cambrian to Devonian rocks also are prominently featured in many of the state parks, including John Boyd Thacher, Taghanic Falls, Green Lake, Minnewaska, Watkins Glen, Chittenango Falls, and the Catskill Park. Student and professional geologists and paleontologists from all around the world visit New York to see the many classic localities and to further research New York stratigraphy.
Cambrian to Devonian sedimentary rocks of New York State contain the record of many significant events in the history of the earth and its life. Studying the rock succession we can see the uplift and erosion of mountain belts as collisions took place between the ancient eastern edge of North America and other landmasses (e.g., the Taconic island arc, the Avalon microcontinent, and the west margin of Africa in the Ordovician, Devonian, and Pennsylvanian, respectively), widespread deposition of volcanic ashes that originated in Maine and Virginia,, the rise and fall of sea level as ice caps covered and melted in ancient polar Africa, and the movement of shorelines and ancient rivers across broad areas over time. New York’s rocks represent sediments deposited in a broad range of ancient environments, from meandering rivers and adjacent flood plains and river deltas to shallow tropical seas similar to the modern Bahama Islands to deep ocean basins, and many additional settings.