Geology and paleontology of the Santa Maria district, California
- 1 January 1950
- report
- Published by US Geological Survey
Abstract
Stratigraphy, paleontology, and geologic history.-A basement' consisting of igneous rocks of the Jurassic(?) Franciscan formation and sediments of the Upper Jurassic Knoxville formation, and formations of Tertiary and Quaternary age are exposed in the Santa Maria district. The outcrop section, exclusive of the Franciscan, has a maximum thickness of about 10,000 feet, the subsurface section about 27,000 feet. At no locality, however, is either outcrop or subsurface section as thick as the total maxima for the formations. The outcrop Franciscan is made up of altered basalt, gabbro (generally- greatly altered), and minor areas of peridotite and serpentine. The marine Knoxville formation, consisting of shale, thin-bedded calcareous sandstone, and conglomerate, was deposited on the igneous rocks of the Franciscan. It has an outcrop thickness of about 500 feet and a known subsurface thickness of at least 1,250 feet. Aucella cf. A. piochii, which occurs in both outcrop and subsurface sections, suggests late Jurassic...This publication has 0 references indexed in Scilit: