Diatom stratigraphy of the lower Pliocene part of the Sisquoc Formation, Harris Grade section, California

Authors

John A. Barron, USGS
Jack G. Baldau, Ocean Drilling Program, Texas A&M University, College Station, Texas 77843-3469

Document Type

Article

Date of this Version

1986

Comments

Published in micropalentology, vol. 32, no. 4, pp. 357-371, pls. 1-3, 1986.

Abstract

Lower Pliocene diatoms were studied from the Sisquoc Formation and lowermost Foxen Mudstone, exposed along Hams Grade north of Lompoc, California, to refine the diatom biostratigraphy of post-Monterey Formation sediments in California. Sixty-seven diatom taxa were identified in the 25 samples examined from the 790-m thick (2950-ft) section. The diatoms are assignable to the uppermost Nitzschia reinholdii Zone and Thalassiosira oestrupii Zone of Damn (1981), and five tentative subzones for local correlation are proposed. Regional correlations and taxon occurrence are discussed, and the base of the Nitzschia reinholdii Zone is redefined as at the last occurrence of Thalassionema schraderi.