Facies Analysis of the Monterey Formation in the Northern Santa Barbara Channel (1)

Abstract

The Monterey Formation in the northern Santa Barbara Channel was deposited in three distinct depositional environments during the early Mohnian (middle Miocene). Along the northern margin of the channel, the Monterey was deposited in a banktop environment, resulting in a thin and clay-rich (chert-poor) lower Mohnian Stage that is punctuated by disconformities. In contrast, in the middle of the Santa Barbara Channel, the Monterey was deposited in a basinal setting, resulting in a thick and continuous lower Mohnian Stage that is clay poor and chert rich. Between the banktop and the basinal depositional settings is an area that is transitional in character and represents deposition on the slope. These changes in average composition and thickness cause a southward increase in the quality of the fractured Monterey reservoir within the northern Santa Barbara Channel.