Palynology of the Silverado formation (late Paleocene), riverside and orange counties, California

Abstract

A palynological investigation of 24 outcrop samples from Alberbill, Riverside County, and Rancho Mission Viejo, Orange County, California, provided a spore and pollen assemblage of 85 species in 56 genera. The presence of Momipites tenuipolus Anderson and Plicatopollis triradiata (Nichols) Frederiksen & Christopher indicates that the lower member of the Silverado Formation is late Paleocene in age. This refines a previous interpretation of Paleocene age for the Silverado Formation based on megainvertebrate fossils in the upper member.

The abundance of fungal and pteridophyte spores and angiosperm pollen indicate a swampy or lowland bog depositional environment within a paralic deltaic system. Caryapollenites, Cupanieidites, Paraalnipollenites, Plicatopollis, and Momipites pollen in the assemblage indicate a warm temperate influence within a prevailing subtropical climate during the deposition of the Silverado Formation.