The sequence represents a transgression where sea level arises from the land and shoreline moves to the higher grounds. It is caused by a tectonic event like climate change for example ice ages.
The sequence also represents regression, where it occurs in areas of the submerged sea floor, are being exposed above the sea level. It is caused by a tectonic event like orgenies.
The sequence represents unconformity where it shows crustal deformation, sea level variations.Substantial is constituted by the surface between two body rocks.
There is a sequence of angular unconformity where rocks have been tilted and also truncated by erosion. This erosion removes all the uplifted mountain ranges.