Figure 14-Reconstruction (in sequence [animation]) of depth-converted interpretation of seismic profile in Figure 13 to the end of Oligocene time. Backstripping of expanded Miocene deltaic sediments leaves a basinward-thinning wedge of Oligocene sediments (purple) above the detachment. Assuming no salt withdrawal since the end of Oligocene at position 1, backstripping indicates 1.1 km of excess subsidence in this area, certainly an overestimate. The change in sediment overburden thickness from the end of Oligocene to the present is 7 km. Change in water depth (Dw_d) is less than 500 m. Isostatic balance estimates salt withdrawal of greater than 2 km of salt. If change in water depth is less or excess thermal subsidence is less, then more salt withdrawal is required for isostatic balance. (See discussion on subsidence and salt withdrawal in Chapter Appendix). Reconstruction is by the PREP method.