A complex interplay of tectonic, eustatic and oceanographic processes concurred in the development of ‘drowning unconformities’ at the top of the Giumal clastic shelf. Rapid deepening and waning of both volcanic and quartzo-feldspathic terrigenous detritus are mainly ascribed to the global mid-Cretaceous sea-level rise and to rapid thermo-tectonic subsidence at the end of the short-lived Albian magmatic event, possibly related to a mantle plume rising beneath northern India. Intensification of the east-bound oceanic current off the north margin of India after the final break-up of Gondwanaland was responsible for continuous resuspension and minimal accumulation rates around the shelf-break. The associated coastal upwelling favoured impingement of the oxygen-minimum zone on the outer shelf, with glauco-phosphorite deposition coinciding in time with peak global transgressions and ‘anoxic events’ in the world oceans.