Chitinozoan biostratigraphy of the regional Arenig Series in Wales and correlation with the global Lower–Middle Ordovician series and stages

Amberg, Chloé E.A.; Molyneux, Stewart G.; Zalasiewicz, Jan A.; Vandenbroucke, Thijs R.A.. 2023 Chitinozoan biostratigraphy of the regional Arenig Series in Wales and correlation with the global Lower–Middle Ordovician series and stages. Geological Magazine, 160 (3). 511-534. https://doi.org/10.1017/S0016756822001078

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Official URL: http://dx.doi.org/10.1017/S0016756822001078

Abstract/Summary

The Arenig Fawr area of North Wales constitutes the type area for the British Lower to Middle Ordovician Arenig Series and is complemented by sections in the Carmarthen and Whitland areas of South Wales. We describe chitinozoan assemblages from both areas in order to aid correlation of the Arenig Series in its type region with the global Ordovician series and stages. Chitinozoans recorded from Arenig Fawr provide permissive rather than conclusive evidence but suggest that the Henllan Ash Member correlates with the upper Floian Stage Slice Fl3 or lower Dapingian Stage Slice Dp1. Better results were obtained from South Wales where six chitinozoan assemblages are distinguished, ranging in age from late Tremadocian to middle Darriwilian (early Llanvirn). Most species are known from South China, Gondwana and/or Baltica where there are controls on ranges. They show that much of the lower Arenig (Moridunian) succession in South Wales correlates with the upper Floian Stage (Fl3). Correlatives of the lower and middle Floian Stage (Fl1, Fl2), if present, must be represented by the Ogof Hên Formation and lowest Carmarthen Formation. Chitinozoan assemblages from the upper Arenig Series (Fennian Stage) are more readily correlated with Gondwanan biozones and indicate correlation of the Fennian Stage with the Dapingian and lower Darriwilian (Dw1) stages. The middle Arenig Whitlandian Stage is constrained in South Wales to an interval from the uppermost Floian Stage to the basal Dapingian Stage, resulting in an inferred increased rate of sediment accumulation.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	https://doi.org/10.1017/S0016756822001078
ISSN:	0016-7568
Date made live:	12 Jan 2023 14:23 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/533859

Item Type:

Publication - Article

Digital Object Identifier (DOI):

https://doi.org/10.1017/S0016756822001078

ISSN:

0016-7568

Date made live:

12 Jan 2023 14:23 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/533859