Italy as a Global Reference Area for Chronostratigraphy: From Ratified GSSPs to Emerging Candidates

Global Boundary Stratotype Sections and Points (GSSPs) formally define the boundaries of the Geologic Time Scale and represent the highest standard for global stratigraphic correlation. Their formalization requires continuous, expanded, and accessible successions that record globally correlatable signals across multiple proxies. Within this framework, Italy stands out as a unique reference area, hosting an exceptional concentration of ratified GSSPs as well as high-quality candidate sections that continue to refine the chronostratigraphic scale. From the Southern Alps to the Apennines and Sicily, Italian sedimentary basins preserve some of the most complete marine records on Earth, spanning key intervals from the Paleozoic–Mesozoic transitions to the Paleogene, Neogene, and Quaternary. Italy currently hosts 13 ratified GSSPs, including key Quaternary reference sections such as Monte San Nicola (base of the Gelasian Stage, Pleistocene) and Vrica (base of the Calabrian Stage), as well as major Triassic boundaries in the Southern Alps (e.g., Bagolino for the Ladinian and Prati di Stuores for the Carnian). The recently ratified GSSP for the base of the Campanian at the Bottaccione section (Gubbio)—one of the most iconic pelagic successions globally—further reinforces Italy’s central role. Italy also hosts a significant proportion of GSSPs spanning from the Eocene through the Pleistocene. The “Ideale Section” at Montalbano Jonico (Chibanian Stage) represents the only formally ratified auxiliary stratotype (SABS) at the global scale, further underscoring the central role of Italian sections in refining chronostratigraphic correlations. Italy is equally pivotal for the future development of stratigraphy. Several sections—most notably Pizzo Mondello (Norian Stage), as well as Pignola-Abriola (Rhaetian Stage) and Contessa Highway (Bartonian Stage) —represent leading candidates for new GSSPs. These successions integrate biostratigraphy, magnetostratigraphy, and chemostratigraphy at an exceptional resolution, capturing rapid environmental and biotic changes that are critical for identifying globally synchronous markers. This pre-eminence reflects a unique combination of factors, including continuous, tectonically controlled sedimentation, outstanding exposure conditions, and a long-standing tradition of stratigraphic research within the international ICS community. Italy should therefore be regarded not merely as a contributor, but as a global benchmark for chronostratigraphy. Its stratigraphic archives underpin a substantial portion of the Geologic Time Scale and continue to set the standard for future boundary definition. At the same time, the recognition and promotion of Italian GSSPs as key geoheritage sites represent a strategic priority for fostering education, public engagement, and international geoscientific cooperation.