Marine carbonate factories: a global model of carbonate platform distribution

Abstract

Platform carbonates are a major component of the Earth system, but their spatial distribution through geological times is difficult to reconstruct, due to the incompleteness of geological records, sampling heterogeneity, and their intrinsic complexity. Beyond this complexity, carbonates are not randomly distributed in the world oceans, neither in the modern nor in the past, and thus, global trends exist. In the present review, we focus on the understanding of the spatial distribution of carbonate production at a global scale. We use a deterministic approach, which focuses on discriminating components, stratigraphic architectures, and environmental features to relate shallow-water carbonate production to oceanographic parameters. The work is based on extensive literature reviews on carbonate platforms. Ecological niche modelling coupled with deep-time general circulation models is used to calibrate a predictive tool of carbonate factory distribution. A carbonate factory function is set up that is based on sea-surface oceanographic parameters (temperature, salinity, and primary productivity). The model was tested using remote-sensing and in situ oceanographic data of Modern times, while outputs of paleoceanographic models are utilized for Lower Aptian (Cretaceous) modelling. The approach allows determining four neritic carbonate factories that are called the marine biochemical, photozoan, photo-C-, and heterozoan factories. The model finely simulates the global distribution of Lower Aptian and Modern carbonate platforms. Carbonate factories appear to thrive for specific ranges along the environmental gradient of carbonate saturation. This conceptual scheme appears to be able to provide a simple, universal model of paleoclimatic zones of shallow-water marine carbonates.