Foraminiferal biofacies and depositional environments of the Burdigalian mixed carbonate and siliciclastic Dam Formation, Al-Lidam area, Eastern Province of Saudi Arabia

Four outcrops along a west to east transect in the Al Lidam escarpment of Saudi Arabia were investigated to understand the vertical and lateral distribution of foraminiferal assemblages for paleoenvironmental reconstruction. The samples were processed using the standard acetic acid method, which extracts foraminifera from lithified carbonate rocks without destroying the fossil content. The foraminiferal assemblages from the Dam Formation are dominated by calcareous porcelaneous Miliolina (Quinqueloculina, Peneroplis, Triloculina, Cornuspira, Sigmoilinita, Coscinospira, Spirolina, Pyrgo, Borelis), followed by hyaline genera (Elphidium sp., Ammonia, Cibicides, Discorbinella) and a minor percentage of agglutinated forms, e.g., Textularina. The high percentage of calcareous porcelaneous taxa and the absence of planktonic foraminifera indicate that the Dam Formation was deposited in a restricted carbonate platform environment, very shallow hypersaline shallow marine, gently sloping ramp (inner ramp to mid ramp) which ranges from supratidal to subtidal with local reef patches towards the basin. The formation was deposited in an arid subtropical climatic environment with water temperatures ranging from 20 to 35 °C. Based on the observed assemblage composition, the present day Arabian Gulf can be considered as a modern analogue for the Dam Formation during Miocene times.