Thalassiosira praeoestrupii- A New Diatom Species for Recognizing the Miocene/Pliocene Epoch Boundary in Coastal California

Authors

Michael P. Dumont, University of California, Berkeley
Jack G. Baldauf, Texas A&M University, College Station, Texas
John A. Barron, USGS

Date of this Version

1986

Comments

Published in micropaleontology, vol. 32, no. 4, pp. 372-377, pl. I, 1986.

Abstract

A new diatom species, Thalassiosira praeoestrupii Dumont, Baldauf and Barron, is described. The first occurrence of T. praeoestrupii in coastal California diatom-bearing outcrops occurs between the last occurrence of Rouxia californica at 6.0 Ma, and the first occurrence of Thalassiosira oestrupii at 5.1 Ma. The latter two species have customarily been used to identify the Miocene/Pliocene boundary. Paleomagnetic studies at Santa Cruz, California, demonstrate that the first occurrence of T. praeoestrupii coincides with the top of magnetic polarity Chron 5, which closely approximates the Miocene/Pliocene Epoch boundary.