Comment on “Late Cenozoic sea level and the rise of modern rimmed atolls” by Toomey et al. (2016), Palaeogeography, Palaeoclimatology, Palaeoecology 451: 73–83

Abstract

Toomey et al. (2016) present a credible new model to explain variations in the formation of Pacific Ocean atolls through the Late Cenozoic, thus accounting for contemporary differences in atoll morphology. While we do not contradict the primary influences of dissolution and sedimentation processes, we suggest that the influence of submarine landsliding should not be ignored. Multiple slope failures exist on the flanks of many atolls. When large submarine landslides affected a significant portion of a palaeo-atoll rim, this had the potential to open up an atoll lagoon allowing much freer circulation between the lagoon and the ocean. Our atoll flank collapse model therefore provides an additional mechanism for an enclosed atoll lagoon to become a ‘leaking bucket’ system and an atoll more likely to evolve into the ‘empty bucket’ form with later sea-level rise. Submarine landsliding adds additional support for the new model of atoll formation proposed by Toomey et al.