Quantifying the paleogeographic driver of Cretaceous carbonate platform development using paleoecological niche modeling

Abstract

Platform carbonates are a major component of the Earth System but their spatial extent through geological time is difficult to reconstruct, due to the incompleteness of the geological record, sampling heterogeneity and their intrinsic complexity. Here we use coupled ecological niche modeling and deep-time general circulation models to predict the occurrence of platform carbonates at the global scale during the Cretaceous. Specifically, niche modeling uses fuzzy logic to predict probable occurrence of platform carbonates as a function of sea-surface temperature, sea-surface salinity, primary productivity and water depth. The first three parameters derive from Cretaceous global paleoclimatic simulations using a coupled ocean-atmosphere general circulation model, while bathymetry is based on paleogeographical reconstructions. Model predictions are validated with the well-documented and abundant geological data from the Aptian. The methodologies developed for the Aptian are subsequently extended to other Cretaceous time intervals. The results of the niche model accurately predict the geographic distribution of Aptian carbonate platforms if a preference for low open-marine productivity levels is assumed for the rudist-dominated carbonate factories. However, if a preference for high productivity levels is assumed, the modeling results do not match the reported global distribution of Aptian carbonate platforms. From the Early Cretaceous into the Late Cretaceous sea level rose and the continents, on average, moved into lower latitudes. The model predicts a corresponding increase in the extent of the carbonate platforms, mainly due to the increasing extent of shallow-water environments available to carbonate development. These results indicate that long-term sea-level rise may have been a major factor responsible for the increase in the area of platform carbonates during the Cretaceous.