The lag time is the time when sediments that were deposited during the preceding period of subaerial exposure are eroded or modified.

Since the sediment is erroded we don't know exactly what was there or how long the time lasted before it was modified or wiped away. Hence it makes studying the beginning development of the carbonate factory very difficult.

This time period is also controlled by the lag depth, which is the water depth needed for effective circulation which allows the devlopment of an active carbonate factory. The depth is typically 1 to 2 meters.

Index to carbonate shelf sediments below or to link back to USC website on sequence stratigraphy click here