Dinoflagellate cyst stratigraphy of the Kimmeridge Clay (Upper Jurassic) from the Dorset coast, Southern England

Abstract

Abstract A palynological investigation of the Upper Jurassic Kimmeridge Clay in its type area (Dorset, southern England) identified twenty‐five stratigraphically useful dinoflagellate cyst datums (range tops and bases). These have enabled the Kimmeridgian dinoflagellate cyst zonation of Woollam and Riding (1983) to be substantially refined. Eleven subzones are established within Woollam and Riding's Gonyaulacysta jurassica ‐ Scriniodinium crystallinum (Gj/Sc), Scriniodinium luridum (SI) and Glossodinium dimorphum ‐ Dingodinium tuberosum (Gd/Dt) zones, which span part of the Oxfordian and the entire Kimmeridgian stages. The indices of these zones, and the overlying Ctenidodinium culmulum ‐ Ctenidodinium panneum (Cc/Cp) Zone, are amended and their definitions revised. The dinoflagellate cyst floras are broadly comparable to others from northern Europe, but show certain differences with coeval Tethyan assemblages. Two new skolochorate dinoflagellate cyst species are described, Oligosphaeridium patulum sp. nov. and Systematophora daveyi sp. nov.