Abstract: Quantitative Analysis of Holocene Diatom Assemblages from Suisun Bay, CA

Kathleen E. Docherty, Lisa D. White, Roberto Anima

Holocene diatoms were examined in a two-meter core from Suisun Bay, in northeastern San Francisco Bay. The core was subsampled at ten-centimeter intervals as part of a multidisciplinary project on the Holocene sedimentation history of San Francisco Bay. Sediment in the core consists predominantly of laminated silt and mud. Twenty strewn slides were examined and up to 300 diatom valves were counted per slide. Dominant taxa throughout most of the core include various species of Thalassiosira, numerous species of brackish water Nitzschia, Actinocyclus normanii, Thalassionema nitzschioides, and Cyclotella stylorum. The diatom assemblages reveal sustained interaction of marine and nonmarine influences in an estuarine environment. These analyses repre ent the first detailed study of diatom paleoecology for the latest Holocene in northern San Francisco Bay.

AAPG Search and Discovery Article #90958©1995 AAPG Pacific Section Meeting, San Francisco, California