Glacio-eustatic sea-level changes and their magnitude in the Telychian–Sheinwoodian (Silurian) of England and Wales

Telychian to Sheinwoodian (Silurian) rocks of the Midland Platform and the adjacent shelf (UK) document the onlap and transgression of an irregular unconformity surface by a shallow sea. Integrated borehole and outcrop studies have allowed for the development of a sequence stratigraphic model and a eustatic sea-level curve, the magnitude of which has been scaled using rocky-shorelines, and changes in benthic assemblages and facies, minus the effects of subsidence. Notwithstanding uncertainties in the datasets used, the timing of transgressions and regressions matches globally identified sea-level changes, and both the durations of sea-level change and their magnitudes are indicative of glacio-eustasy. Our long-term sea-level curve identifies a rise in sea-level from middle to late Telychian times, followed by a fall, which culminates in a middle Sheinwoodian sea-level low. Both the timing and magnitude of sea-level changes match contemporaneous climate variations, and these indicate an early-mid Telychian warming trend followed by late Telychian cooling, which peaks in the middle Sheinwoodian. Notably, the overall magnitude of the long-term regression associated with the late Telychian to middle Sheinwoodian is comparable with that reported from the end-Ordovician glaciation, but likely reflects a more protracted episode of cooling, ice sheet growth, and sea-level fall.