Biostratigraphy, sequence stratigraphy and gamma-ray spectrometry of the Tournaisian-Viséan boundary interval in the Dublin Basin

Abstract

A study of three carbonate and carbonate-siliciclastic sections at the Tournaisian-Viséan (Tn-V) boundary in the Dublin Basin (Ireland), has been carried out using high resolution foraminiferal biostratigraphy and gamma-ray spectrometry. The aim was to identify the Tn-V boundary and trace correlatable log patterns in different environmental settings of the Dublin Basin. The foraminiferal fauna in the heterozoan and mixed heterozoan-photozoan (foramderm and bryonoderm extended) late Tournaisian shallow ramp facies and its calciturbidite products is taxonomically impoverished and resembles the similar impoverished foraminiferal associations of western Canada interpreted as reflecting upwelling zones. The increase of photozoan bioclasts which occurs in the latest Tournaisian is accompanied by the entry of important foraminiferal guides of the Tn-V boundary interval. The combination of biostratigraphic and spectral gamma-ray data proved to be a useful tool for the identification of the sequence boundary just below the Tn-V boundary across the different environmental settings of the Dublin Basin. The recognized sea-level fall is correlatable across the London Brabant Massif from western Ireland through to England, South Wales and Belgium.•

Latest Tournaisian–late Viséan foraminiferal biozonation (MFZ8–MFZ14) of the Valiabad area, northwestern Alborz (Iran): geological implications

“…gadukensis in the Mokrá quarry (Czech Republic); Kalvoda et al . (, Figs. 12.O, 13.H) illustrated other L .…”

High resolution biostratigraphy of the Tournaisian-Viséan boundary interval in the North Staffordshire Basin and correlation with the South Wales-Mendip Shelf

“…3). The entry of Eoparastaffella ovalis M2 is very close to the entry of E. simplex and because in many sections E. ovalis M2 is more common than E. simplex, it can be used as an alternative criterion to identify the T-V boundary (Devuyst 2006;Kalvoda et al 2010Kalvoda et al , 2011. In accord with the base of the Arundian, the base of MFZ10 coincides with the entry of Archaediscidae represented by Ammarchaediscus and Planoarchaediscus, while the evolutionary younger Uralodiscus and Glomodicus occur in the upper part of the zone (Devuyst & Hance in Poty et al 2006).…”

“…In this respect gammaray spectrometry (GRS) has already proved as a useful tool in tracing sea-level oscillations, supplementing biostratigraphy and improving dramatically the resolution of stratigraphic correlations , Delius et al 2001, Doveton 1994, Hladil et al 2006, Rider 1999, Thibal et al 1999. The successful application of this method for correlating the T-V boundary interval in the Dublin Basin, Ireland was clearly demonstrated by Kalvoda et al (2011). Although this Irish study demonstrated the utility of foraminifera in high resolution stratigraphy it also demonstrated that foraminiferal assemblages were strongly facies controlled and that detailed microfacies study is required in order to realise their true stratigraphic potential.…”

Mississippian (Early Carboniferous) sequence stratigraphy of the Rhenish Kulm Basin, Germany

“…That study is an impressive example of the interplay between sea-level induced flooding and emergence and the contemporaneous block faulting and demonstrates the applicability of sequence stratigraphic methods in tectonically active regions. Further, Bábek et al (2010Bábek et al ( , 2013 and Kalvoda et al (2011) showed the powerful application of outcrop gammaray spectrometry and magnetic susceptibility in combination with carbonate facies stacking patterns and high resolution biostratigraphy to trace the sequences close to the TournaisianViséan boundary. In their studies they could correlate ramp to intraplatform basin sections around the Wales-Brabant Massif in the British Isles and Belgium, as well as at western margin of the RKB in the Velbert anticline.…”