Dyserth Quarry, Dyserth Quarry Limestone Formation (Carboniferous of the United Kingdom)

Also known as 1989 list Dyserth Quarry, Dyserth Quarry Lilmestone Formation. Some exposures at Pentre-bach Quarry

Where: Wales, United Kingdom (53.7° N, 2.7° W: paleocoordinates 8.5° S, 0.0° W)

• coordinate stated in text

• outcrop-level geographic resolution

When: Dyserth Quarry Limestone Formation, Arundian (345.0 - 342.8 Ma)

• The contact of this formation with the underlying Foel Formation is observed at the top of Pentre-bach Quarry North, below a thick, coarse-grained dolomite bed. The lowest beds are exposed in Dyserth Quarry, which forms the type section for this formation, lie close to its base.

• group of beds-level stratigraphic resolution

Environment/lithology: open shallow subtidal; lithified, coarse-grained, brown grainstone and lithified, coarse-grained, brown packstone

• The Dyserth Quarry Limestone Formation is readily distinguished from the underlying Foel Formation by the massive character of its limestones and the absence of interbeddedd siltstones and mudstones. Over 60m of pale brown, coarse-grained packstones and grainstones showing small scale cross lamination are exposed in the quarry. They yield only a sparse macrofauna of brachipods and corals.

•The depositional environment of the Dyserth Quarry Limestone Formation suggests a change to more open marine conditions in a middle shelf setting where siliciclastic input wass very much reduced, and the limestones are consequently much cleaner. However, it was still dominantly a shallow-water, wave-influenced subtidal shelf environment. This can be inferred from the well-rounded and sorted bioclasts, coated grains, strongly micritized grains, and abundant cross-stratification in the packstone/grainstine lithofacies.

Size class: macrofossils

Collection methods: All specimens are housed in the British Geological Survey Collection, Keyworth, Nottingham, England (BGS)

Primary reference: I. D. Somerville, A. R. E. Strank, and A. Welsh. 1989. Chadian faunas and flora from Dyserth; depositional environments and palaeogeographic setting of Visean strata in Northeast Wales. Geological Journal 24(1):49-66 [J. Alroy/C. Simpson/C. Simpson]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 41454: authorized by John Alroy, entered by Carl Simpson on 14.07.2004

Creative Commons license: CC BY (attribution)

Taxonomic list

Strophomenata
 Productida - Monticuliferidae
 Productida - Rugosochonetidae
Anthozoa
 Auloporida - Syringoporidae
Syringopora sp. Goldfuss 1826 tabulate coral
 Stauriida - Lithostrotionidae
Siphonodendron cf. martini Milne-Edwards and Haime 1851 horn coral
 Stauriida - Palaeosmiliidae
Palaeosmilia murchisoni Milne-Edwards and Haime 1848 horn coral
 Stauriida - Aulophyllidae