2026/04/16 by Íñigo Vitón, María José Comas-Rengifo, Luís V. Duarte +2 · 1 voice
Earth and Planetary Sciences · #Geological formations and processes #Paleontology and Evolutionary Biology #Paleontology and Stratigraphy of Fossils
paper · doi:10.1016/j.earscirev.2026.105507
openalex publication_date 2026/04/16 · openalex created_date 2026/04/17 · openalex updated_date 2026/05/15
The uppermost Sinemurian and the Sinemurian–Pliensbachian transition represent a critical interval for Lower Jurassic chronostratigraphic correlation. This study presents a comprehensive review of published ammonite-based chronostratigraphic data for this interval, using the Polvoeira-Água de Madeiros (Lusitanian Basin, western Portugal) and Rodiles East (Asturian Basin, northern Spain) sections as key references. These sections are expanded and display a continuous and complete ammonite succession, allowing high-resolution correlation with the Pliensbachian GSSP at Robin Hood's Bay (UK). A critical compilation of well-documented stratigraphic sections from northwestern Europe, the Mediterranean and Austroalpine domains, and selected Pacific localities allows the evaluation of the consistency, completeness, and limitations of ammonite zonal and subzonal correlations. The analysis highlights pronounced differences in stratigraphic completeness between the Oxynotum and Raricostatum zones, the latter with higher chronostratigraphic resolution and allowing more reliable interbasinal correlations. Integrated stratigraphic and palaeoenvironmental evidence indicates that transgressive-regressive cycles exerted a strong control on ammonite distribution, provincialism, and evolutionary turnover across the study interval. A major flooding episode around the Macdonnelli Subzone coincides with the widespread expansion of Leptechioceras , whereas the Raricostatum–Jamesoni transition is marked by significant faunal turnover associated with sea-level change and termination of a negative carbon isotope excursion. This review places the Iberian sections as essential benchmarks for refining the Early Jurassic timescale and identifies robust chronostratigraphic tie points, highlights remaining uncertainties, and provides a refined framework for interregional correlation of the uppermost Sinemurian and the Sinemurian–Pliensbachian transition.