the acadian orogeny experienced at least three major phases of deformation, and in places, unconformities were recognized. these phases were called tectophases, and represented the sequence of collisions that occurred from the avalonian terranes accreting to laurentia. as a result of these tectophases, deltas developed on the adjacent parts of the stable craton, eastern margin of laurentia. these deltas are described as foreland-basin, delta-complex clastic wedges, which are responsible for the large volumes of sediment input into the appalachian basin.