Biostratigraphy of Santa Maria Area: ABSTRACT

Abstract

The Santa Maria area is defined as that portion of northwestern Santa Barbara County bounded on the north by the Santa Maria River, on the west by the Pacific Ocean, on the south by the Santa Ynez River, and on the east by Fugler Point, East Cat Canyon, Gato Ridge, and Zaca Creek fields, and the town of Buellton. In the Los Alamos syncline, 16,000 feet of sediments overlie Franciscan (Jurassic ?) basement or the Knoxville (Jurassic ?) Formation. Included in this sequence are: Lospe (Oligocene ?), fine to coarse, non-marine clastics; Point Sal (middle Miocene), siltstones, mudstones, and sandstones; Monterey (middle and upper Miocene), siliceous, cherty, and calcareous shales; Sisquoc (upper Miocene-lower Pliocene), diatomites, diatomaceous siltstones, and sandstones; Foxen (upper Pliocene), mudstones; and Careaga (upper Pliocene), sandstones. Essentially non-marine beds of Pleistocene to Recent age overlie the Careaga. Megafossils, foraminifers, radiolarians, and diatoms are present in the marine Tertiary beds. The most effective correlations are foraminiferal. Based on a virtually complete composite of cores, the section has been divided into 18 foraminiferal zones: 5 in the Point Sal, 5 in the Monterey, 4 in the Sisquoc, 2 in the Foxen, and 2 in the Careaga. In a large part of the area, the rocks are highly siliceous and essentially barren of Foraminifera, but usually reasonably satisfactory correlations based on micro-lithology can be made. End_of_Article - Last_Page 1083------------