Rising water is shaping the future of Louisiana and the Gulf Coast.
In a recent paper in Geophysical Research Letters, Dr. Oppo investigated the lateral tranfer of overpressure in the shallow subsurface and how it can lead to the intrusion of poorly consolidated mud into the overlying sediments.
Unconsolidated mud can pierce the overlying sediments in a mechanism called mud diapirism. This process is associated with elevated pressure in the subsurface, which can be a relevant hazard for infrastructures and human society.
The mud is most commonly sourced at great depth and shallow sourced mud diapirs, defined “early burial,” are undocumented outside large river deltas. Dr. Oppo describes the first example of early burial mud diapirism in a different geological setting: the deformed foredeep of Northern Italy.
The overpressure necessary for the mud diapir formation was generated by the lateral transfer of pressure along sedimentary strata. The lateral pressure transfer usually occurs in permeable sandstones, but Dr. Oppo and co-authors infer that here it occurred within low-permeability sediments. This modality of lateral transfer has not been described before and has potential implications for predicting overpressure in areas not commonly affected by this phenomenon.