Carbonate platform drowning geometries: processes, paleoclimate and prediction

Deciphering records of deep-time sea level, climate, and oceanographic variation from drowned carbonate platforms is useful, including perhaps to help predict risk of drowning on modern platforms experiencing anthropogenic sea-level rise. However, prediction is complicated by incomplete understanding of how observed platform geometries record different drowning processes. Parameter space analysis of numerical stratigraphic forward model results indicates that backstepping drowning geometries occur when cross-platform sediment transport redistributes sediment and drives complex autogenic feedbacks that help maintain a broad shallow-water platform-top area. In contrast, without sufficient sediment transport on platforms dominated by in situ production, pinnacle or flat-top drowning geometries tend to be produced. These results suggest platform drowning geometries represent a complex mix of controlling factors that, with careful interpretation, could provide robust information about deep-time climate and sea-level change, and may also help predict evolution of modern platforms responding to rising global sea level.