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How did the Catskill Delta form during the Devonian Period?

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Devonian paleogeography — Devonian Period Distribution of landmasses, mountainous regions, shallow seas, and deep ocean basins during the early Devonian Period. Included in the paleogeographic reconstruction are the locations of the interval's subduction zones.

The Catskill Delta formed during the Middle and Late Devonian Period as a result of the Acadian orogeny, a significant mountain-building event caused by the collision of the Avalonia Terrane with the North American Plate.12

As the Appalachian Highlands were uplifted during this orogeny, numerous streams flowed westward from the rising mountains, transporting vast amounts of sediment. These sediments accumulated to construct a large, compound delta across what is now the northeastern United States. The Catskill Delta represents the westernmost of the clastic sedimentary wedges produced by this tectonic activity. Over time, the delta expanded, creating a broad coastal lowland extending more than 320 km, while its submerged portions extended into present-day Ohio.12