Integrated Ladinian bio-chronostratigraphy and geochrononology of Monte San Giorgio (Southern Alps, Switzerland)

A groundbreaking study refines the age of Monte San Giorgio's (UNESCO World Heritage Site) Ladinian marine vertebrate faunas to substage and zone levels, revealing a 4-million-year span significantly shorter than previously assumed. High-resolution single-zircon U–Pb dating on volcanic ash layers intercalated in biostratigraphically-defined Meride Limestone intervals provided precise ages: 241.07 ± 0.13 Ma (Cava superiore beds), 240.63 ± 0.13 Ma (Cassina beds), and 239.51 ± 0.15 Ma (Lower Kalkschieferzone). These ages correlate the San Giorgio Dolomite and Meride Limestone with reference sections at Bagolino, while also showing higher sedimentation rates at Monte San Giorgio compared to pelagic conditions in the Buchenstein Formation. The study enables correlation of vertebrate faunas with the Prosanto Formation's record, advancing our understanding of Triassic paleontology.

Stockar, R., Baumgartner, P. O., & Condon, D. (2012). Integrated Ladinian bio-chronostratigraphy and geochrononology of Monte San Giorgio (Southern Alps, Switzerland). Swiss Journal of Geosciences, 105(1), 85–108. https://doi.org/10.1007/s00015-012-0093-5