New observations on the inoceramid biostratigraphy of the higher part of the Upper Turonian and the Turonian – Coniacian boundary transition in Poland, Germany and the UK

Abstract

New studies of sections in southern England (Bridgewick Pit, Downley, Shoreham Cement Works Quarry), eastern England (Kiplingcotes Station Quarry, Arras Road Pit), Germany (Salzgitter-Salder Quarry, a potential candidate GSSP for the Coniacian Stage) and central Poland (Słupia Nadbrzeżna, another potential candidate GSSP) have enabled a re-evaluation and refinement of the inoceramid biostratigraphy of the higher part of the Upper Turonian and the Turonian–Coniacian boundary transition. The inoceramid record at Słupia Nadbrzeżna below the terminal Turonian entry of Cremnoceramus is shown to be more complete than at the standard Salzgitter-Salder Quarry section. A new inoceramid event (Inoceramus lusatiae Event) identified at Słupia Nadbrzeżna is inferred to be present at the Sonnenberg Quarry, Waltersdorf, the type locality of Inoceramus lusatiae, as well as of I. glatziae and Cremnoceramus waltersdorfensis, and it is possibly represented in the condensed Navigation Hardgrounds in southern England. The absence of this event at Salzgitter-Salder suggests a significant hiatus. An inoceramid assemblage characterised by a taxon of uncertain affinities that immediately precedes the flood occurrence of Cremnoceramus (waltersdorfensis 1 Event) at Salzgitter-Salder has been identified at a comparable biostratigraphic position in eastern England (Yorkshire) and, tentatively, also in southern England. Inoceramids from this assemblage in the UK had previously been incorrectly assigned to Cremnoceramus waltersdorfensis and the basal Coniacian marker taxon, C. deformis erectus. The position of the base of the Coniacian has accordingly been revised upwards in both the southern and eastern England successions.