Pliocene rocks in the Ventura basin, including the part under the Santa Barbara Channel, provide an excellent area to study a strongly deformed but essentially intact turbidite basin. Conglomeratic beds, containing typical turbidites, are present along the northern margin of the basin.

Isopach, sand-isolith, and sand-percentage maps of the Pliocene Repetto and Pico Formations in the eastwest Central basin show thick deposits bounded on both sides by thinner deposits in the Rincon trend on the north and the Montalvo trend on the south. Deposition was controlled by partly effective fault barriers on the north and south margins of the Central basin. Sand-isolith and sand-percentage maps indicate local increases in sand in the north on the Rincon trend suggesting the presence of ancient subsea fans in the Repetto and lower Pico. The overall decrease in sand on the west denotes a major influx of sand from the east down the Central basin axis. The first influx of sand from the southern margin of the basin is found on the sand-percentage map of the middle Pico "A." Deposit on of sand was also affected by topographic highs associated with growing faults and anticlines.

Distribution, textural properties, primary structures, and microfauna of sandstones in the Ventura basin are comparable to the modern deposits in the nearby Santa Monica basin. Stratigraphic maps reveal Pliocene subsea fans, and observations of outcrops and cores show the same type of beds as described in the Santa Monica basin. Hence, sedimentation was controlled by sand deposition in and at the foot of submarine canyons in the form of subsea fans.

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