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The Salinas basin has predominantly barren surface anticlines. The heavy oil giant, San Ardo, was found accidentally on a surface syncline. Finding new traps in this basin requires stripping back the stratigraphy to the time of accumulation, generally late Miocene. One starts at the top with the best available surface geology and geomorphology. The tilted Gabilan Mesa peneplain surface can be untilted by isopaching the thickness from the Mesa surface to the top of the Miocene. At this point we have a map of the structure before the late Pliocene to Recent deformation. San Ardo shows up at this point with 400 ft (122 m) of closure exactly coinciding with the present outline of the oil field and matching the 400-ft (122 m) oil column, in marked contrast to the present day structure cont urs on the producing horizons. Further isopaching of discrete stratigraphic intervals within the upper part of the Miocene produces a picture of the structure shortly after the deposition of the producing zones. In addition, shoreward sand strandlines and seaward sand shale-up lines can be defined. Analysis of this geologic history also shows the probable location of deltaic areas and longshore bars. Early loci of oil accumulation and wedge edges of permeability are apparent from this synthesis. Several small oil fields of the Salinas basin have been found deliberately by unraveling the subtle geologic history to the time of accumulation and deposition.

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