Cenozoic Coccolith Collection of David Bukry in Oregon and Washington, USA

Micropaleontological data have provided essential stratigraphic age control for geologic investigations in the Cascadia forearc, such as the Coast Range-Olympic Mountains and Puget-Willamette Lowland west of the Cascade Range. Foraminiferal assemblages and, later, coccoliths (calcareous nanoplankton) have been the most abundant microfossils recovered from the Cenozoic sequence. The usefulness of coccolith assemblages for establishing the Cenozoic stratigraphic framework (especially the Paleogene) in western Oregon was brought to the attention of Parke D. Snavely, Jr. in the 1960s by a letter from Dr. M. N. Bramlette of the Scripps Institution of Oceanography. Dr. Bramlette reported to Snavely that coccoliths in the Tyee Formation of western Oregon are correlative to “Laiming’s A2 zone of the Canoas Member” of the Kreyenhagen Formation in California (Bukry and Snavely, 1988). Dr. David Bukry, also of the USGS, joined Snavely’s geologic investigation team in the mid-1960s and provided the coccolith zonal assignments for many of the Cenozoic units in the Cascadia forearc. Coccolith information was originally reported to the collector in written form. Report sheets, accumulated over the past 30 years, served as the source of the data entered in the coccolith database.