Modern and relict foraminiferal biofacies from a carbonate ramp, offshore Kuwait, northwest Persian Gulf

Benthic foraminifera on the northern Persian Gulf carbonate ramp are excellent indicators of the depositional environment. They are moderately diverse, vary in distribution along a depth gradient, and are used to subdivide the ramp of offshore Kuwait. The inner ramp is characterized by a Peneroplis-Elphidium crispum assemblage (<5 m water depth); the mid ramp may be subdivided into a shallower miliolid assemblage (similar to 5.5 m water depth) and a deeper miliolid- Elphidium assemblage (11-18 m); the outer ramp (>18 m) comprises mainly an Asterorotalia-Elphidium assemblage, and the Elphidium-Nonion assemblage. The change from the (porcelaneous-dominated) miliolid mid to (hyaline-dominated) Asterorotalia outer ramp assemblages corresponds with a change in biofacies from clast-supported to mud-supported and the summer thermo-cline. Agglutinated forms are most common in intermediate depths of 5.5-16 m. Depositional energy, substrate, and possibly temperature are the major factors controlling foraminiferal distribution. Preservation stages include pristine, slightly and heavily damaged, relict, and reworked specimens. Foraminiferal distributions do show general similarities to the Cenozoic carbonate ramp models, however larger benthic foraminifera are rare. Despite these limitations, foraminiferal distribution patterns in the northern Persian Gulf may serve as useful modern analogues for carbonate ramp deposits in shallow marginal and epicontinental seas in the fossil record.