Depositional environments of the Simmler Formation in Southern Cuyama Valley, Santa Barbara and Ventura Counties, California

The Simmler Formation (Oligocene (?)-early Miocene) of the southern Cuyama Valley area in Santa Barbara and Ventura Counties, California, is a nonmarine sequence overlying pre-Oligocene sedimentary and igneous rocks and underlying the Vaqueros Formation. The Simmler is exposed in a narrow, folded strip along the northern side of the Ozena fault. Eight members, herein informally designated A through H, are recognized. Rocks of Members A and B consist of southeastern fluvial conglomerate, sandstone, and mudstone and northwestern sabkha claystone and mudstone deposits. The fluvial deposits originated from low-sinuosity meandering streams which in turn flowed into locally evaporative sabkha areas. A relatively greater abundance of gypsum in Member B may indicate that more permanent evaporative depressions characterized the Member B depositional basin. Rocks of Member C consist of a lower sand and gravel of traction-flow origin and an upper muddy conglomerate of debris-flow origin, all of which probably formed on alluvial fans. (See more in text)