1. n. 
An exploration and production play type in which prospects exist below salt layers. Until relatively recently, many explorationists did not seek prospects below salt because seismic data had been of poor quality below salt (i.e., it was not possible to map traps accurately) or because they believed that reservoir-quality rock or hydrocarbons did not exist below salt layers. Advances in seismic processing and compelling drilling results from exploration wells encouraged companies to generate and drill prospects below salt layers, salt sheets and other previously disregarded potential traps. The offshore Gulf of Mexico contains numerous subsalt-producing fields, and similar areas are being explored internationally.