What was the Acadian orogeny?

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Blue Ridge, Appalachian Mountains — Appalachian Mountains Blue Ridge, part of the Appalachian Mountains.

The Acadian orogeny was a significant mountain-building event that occurred during the Devonian Period, approximately 416 to 359.2 million years ago. This tectonic activity affected a vast region stretching from present-day New York to Newfoundland.1

The process involved the compression and folding of deposits within the Appalachian Geosyncline, transforming them into a mountain chain. Geologists attribute this orogeny to the collision of the Avalonia Terrane with the North American Plate, driven by the eastward subduction of the proto-Atlantic.1

Evidence of this event includes:
* Regional metamorphism and deformation of rocks.1
* The presence of igneous intrusions and angular unconformities.1
* Significant uplift that resulted in the formation of clastic sedimentary wedges, such as the Catskill Delta in New York and Pennsylvania.1

The activity was most intense in Maine and southern New England before spreading westward throughout the Devonian period.1