Salt expulsion triggered by prograding clinoforms in the SW Valencia Trough (SE Spain)

The impact of salt mobilisation on prograding clinoforms in salt-bearing basins has been documented by several studies. In this work, we have studied a Plio-Quaternary prograding megasequence lying in the SW Valencia Trough in eastern Iberia, aiming to determine the influence of halokinesis on the geometry, extension and trajectory of the prograding clinoforms. Using an integrated dataset comprising 2D seismic profiles and wellbore data, we constructed three restored cross-sections that depict a progradational megasequence predominantly affected by salt-related structures located on the continental shelf. The sequential restorations of the cross-sections illustrate how the Pliocene-Quaternary depocentre of the prograding shelf wedge was controlled by dip-directed normal faults detaching into Triassic evaporites. The subsequent sedimentary loading produced by the prograding clinoforms was associated with salt withdrawal and the collapse of previously inflated Cretaceous-Miocene salt structures (e.g., passive diapirs). Simultaneously, expulsion of salt triggered the development of diapirs around the depocentres. The clinoform architecture captures lateral changes in accommodation space caused by salt mobilisation during the Pliocene and the Quaternary. These changes, alongside other controlling factors such as relative sea level changes and climate, resulted in different rollover point trajectories of clinoforms. The expulsion of salt has also played an important role in the orientation of the main depocentre, which is NNW-SSE in the southern part and changes to a N-S trend in the north due to the influence of the normal fault system. Temporal differences in accommodation space are therefore be explained by the relationship between the rates of sediment progradation and the salt flow. During the Pliocene, when the rate of sediment progradation was lower than the rate of salt flow, wedge-shaped depocentres developed in the hanging wall of the main normal fault along the margin. This disrupted the architecture of the prograding clinoforms. In contrast, during most of the Quaternary, the rate of sediment progradation exceeded the rate of salt flow. As a result, the salt flow was largely suppressed by a prograding overburden formed by well-preserved clinoforms. The interaction between these processes also affected the evolution of the shelf edge location and geometry. • Clinoform stacking patterns reveal interplay of salt flow and sediment progradation. • Salt mobilisation affects the trajectory of the Plio-Quaternary clinoforms. • Salt-detached faults and related depocentres affect the clinoform architecture. • Shelf edge and depocentre migrated towards NNE.