Part 5/11:
The evolution of the Appalachians continued through several significant periods. Around 400 to 375 million years ago, an additional collision occurred when Avalonia and Baltica collided with Laurentia, forming what is referred to as Euramerica. This event is known as the Acadian Orogeny, a crucial step in the mountain-building process. During the time between these early tectonic events, the margin transitioned into a passive phase, allowing for the deposition of ancient carbonate reef systems, some of which are visible in the Appalachian Mountains today.