Deciphering the fragmentary nature of Cretaceous shallow-water limestone archives: A case study from the subtropical Apennine carbonate platform

Shallow-water carbonate platform sections are valuable archives for the reconstruction of deeptime environmental and climatic conditions, but the low resolution of biostratigraphic schemes associated with frequent sedimentary hiatuses often hampers their precise chronostratigraphic assignment. Moreover, chemostratigraphic correlation of shallow-water sections with well-dated pelagic successions is notoriously difficult and associated with large uncertainties, as shallow-water bulk carbonate archives are particularly prone to the impact of diagenesis. This study examines central Tethyan mid-Cretaceous carbonate platform deposits exposed in the Central Apennines (Italy) suffering several emersion phases, which cause sedimentary gaps of variable duration. The investigated sections (Santa Lucia, Monte La Costa) represent a transect through the Apennine Carbonate Platform, ranging from the lagoonal inner carbonate platform realm towards the platform margin. Although benthic foraminifera are at times scarce and the carbonates evidently suffered diagenetic alteration, high-resolution carbon isotope stratigraphy combined with (rudist and chondrodont shell) strontium isotope stratigraphy enables a correlation of the studied sections with pelagic composite reference curves. A detailed foraminiferal-algal biostratigraphic record of the studied shallow-water sections and their integration into high-resolution carbon and strontium isotope stratigraphy is presented. This approach allows precise estimates of the time lost in major sedimentary hiatuses, three of which were identified at the Santa Lucia locality. There, long-lasting hiatuses cover parts of the Early Aptian (3.2 Myr), the Late Aptian (3.3 Myr) and the Late Albian to Cenomanian (14.3 Myr), the latter being associated with formation of karst-filling bauxite. The documentation and dating of sedimentary hiatuses in the Apennine Carbonate Platform sector presented here is essential to correlate emersion phases observed in the perimediterranean region, in particular with respect to the mechanisms of their origin.