Late Miocene (Santa Margarita Sandstone) shallow marine clastics

The Santa Margarita Sandstone of late middle and early late Miocene age is located in the western Santa Cruz Mountains of central California. It represents a marine, tide-dominated, transgressive deposit which, during the early stage of the marine transgression formed a seaway connection between the Pacific Ocean and the interior San Joaquin basin to the east. The strong tidal current flow which developed as a result of this setting caused the deposition and preservation of large-scale, essentially unidirectional cross-bedded sets of shelf sand and gravel.

During this field trip 3 quarry exposures within Scotts Valley (figure 1 and 2) located near the central part of the seaway deposits will be examined observing both lateral and vertical facies relationships as well as textural variations preserved within the Santa Margarita Sandstone. On the last stop, stop 4, located to the west within the seaway deposits both lateral facies relationships in relation to the previous stops will be observed and discussed as well as examine petroleum-saturated sandstones.