Earth and Atmospheric Sciences, Department of


Date of this Version



Whitehead, J. M., and S. M. Bohaty, Pliocene summer sea surface temperature reconstruction using silicoflagellates from Southern Ocean ODP Site 1165, Paleoceanography, 18(3), 1075, doi:10.1029/2002PA000829, 2003.


Copyright 2003 by the American Geophysical Union. Used by permission.


In the modern marine environment the silicoflagellate genus Dictyocha is rare, or absent, south of the Antarctic polar front (APF); the genus Distephanus, in contrast, is dominant. In sediments recovered from ODP Site 1165, 1600 km south of the front, however, three intervals where Dictyocha is abundant are interpreted to represent Pliocene warm events. Comparison of our data with Ciesielski and Weaver’s [1974] modern core top silicoflagellate relationship with sea surface temperature (SST) indicates that at Site 1165 mean annual SST was approximately 5C at 3.7 Ma (event I), and approximately 4C at 4.3–4.4 Ma (event II) and 4.55–4.8 Ma (event III). Event I represents a 5.5C warming, and events II and III represents a 4.5C warming relative to modern mean annual SST. Dictyocha is absent from other Site 1165 Pliocene intervals, which suggests that cooler SST (