Palynostratigraphy of the classic Portland and Purbeck sequences of Dorset, southern England, and the correlation of Jurassic–Cretaceous boundary beds in the Tethyan and Boreal realms
Chris O. Hunt, 2004. "Palynostratigraphy of the classic Portland and Purbeck sequences of Dorset, southern England, and the correlation of Jurassic–Cretaceous boundary beds in the Tethyan and Boreal realms", The Palynology and Micropalaeontology of Boundaries, A. B. Beaudoin, M. J. Head
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Placement of the Jurassic-Cretaceous boundary and its correlation between the Tethyan and Boreal realms are still contentious. The distribution of stratigraphically significant dinoflagellate cysts in the Portland Stone and Purbeck formations of the Isle of Purbeck, Dorset, UK provides a basis for direct correlation between these sections and the type Berriasian in southeast France. The base of the Berriasian – and thus of the currently accepted Jurassic-Cretaceous boundary – most probably lies at the base of the Cypris Freestones in the Purbeck Formation. Miospore correlation between the Dorset sections and ammonite-bearing rocks in the Spilsby Province suggests that the base of the Cretaceous lies close to the base of the Subcraspidites preplicomphalus zone in the Boreal Realm.
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The Palynology and Micropalaeontology of Boundaries
This volume explores geological boundaries in time and space using palynology and micropalaeontology. Boundaries produce distinct signatures in the micropalaeontological record. Diffuse or sharp, gradual or abrupt, boundaries can tell us much about the response of biotic systems to environmental change in both marine and terrestrial realms. Different microfossil groups and geological contexts require their own approaches, definitions and considerations of boundaries. The papers in this compilation capture the current range of thinking on the methodology of boundary identification from biostratigraphical, ecological and palaeoenvironmental perspectives. Contributions span the Cambrian to Miocene and feature many fossil groups (including pollen, dinoflagellates, foraminifera, ostracodes, conodonts, and diatoms). With a strong Canadian and North American focus, the volume also includes contributions from Poland, Egypt, Belgium, Argentina and the United Kingdom.