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Jonathan C. Claoué-Long, P.J. Jones & John Roberts

The age of the Devonian-Carboniferous boundary

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Abstract

The Devonian-Carboniferous boundary is now one of the most securely dated positions in the Phanerozoic column. Coincident with redefinition of the boundary, a thin volcanic layer has been identified 35 cm above the boundary in the Hasselbachtal section in Germany, now one of the auxiliary global stratotypes, and a tuff has been located at a similar biostratigraphic level in Australia. Ion microprobe zircon dating of the two horizons has yielded indistinguishable ages, and indicates 353.2 ± 4.0 Ma (2σ) as the age of the boundary.

Recent previous estimates of the age of this boundary have suggested dates with a spread of 25 Ma. A review of historical contraints shows that this uncertainty rested mainly upon biostratigraphic difficulty in correlating dated volcanics in terrestrial sediments with the type marine stratigraphy. Recognition of a dateable volcanic layer in the Hasselbachtal auxiliary stratotype eliminates this source of doubt. Future refinements of the age of the Devonian-Carboniferous boundary will depend on re-analysis of this uniquely placed volcanic, and this highlights the value of defining stratotypes in the vicinity of known dateable horizons.

To cite this article

Jonathan C. Claoué-Long, P.J. Jones & John Roberts, «The age of the Devonian-Carboniferous boundary», Annales de la Société géologique de Belgique [En ligne], Volume 115 (1992), Fascicule 2 - Devonian-Carboniferous boundary, 531-549 URL : https://popups.ulg.ac.be/0037-9395/index.php?id=1736.

About: Jonathan C. Claoué-Long

Research School of Earth Sciences, Australian National University, GPO Box, 4, Canberra ACT 2601, Australia.

About: P.J. Jones

Bureau of Mineral Resources, GPO Box 378, Canberra, ACT 2601, Australia.

About: John Roberts

Department of Applied Geology, University of New South Wales, Kensington, NSW 2033, Australia.