Sediment Drift Types in Carbonate Platform Settings
Reflection seismic studies of the Bahama and Maldives carbonate platforms exhibit the occurrence of several sediment drifts types in shallow to deep water settings. Drift sediments are composed of an admixture of pelagic and shallow-water components. They are located in the platform interior, on top of drowned banks and around the platforms differing in dimension, architecture and origin. Smaller patch drifts and sheeted drifts appear in the platform interior and on top of drowned atolls. At the platform slopes elongated mounded drifts, periplatform drifts or detached drifts are common. Large deep water basins or channels in the distal part of the platforms are occupied by confined or channel-related drift. They are comparable to their siliciclastic counterparts; however, these bodies are emplaced at a short distance only of the shallow-water carbonate factory. A special drift in carbonate platform setting are delta drifts that are attached to the platform slope in front of large gateways. They consist of a succession of lobes prograding into the basin maintained by a quasi-steady downslope current flow. Over time, several drift types comprising a complex contourite depositional system may fill large platform basins. The documented variability and abundance of drifts emphasize the significant role of current-controlled sediment transport and redistribution in carbonate platform development.
AAPG Datapages/Search and Discovery Article #90350 © 2019 AAPG Annual Convention and Exhibition, San Antonio, Texas, May 19-22, 2019