Micropaleontological study of the Miocene Dam Formation, Eastern Province of Saudi Arabia

Abstract

There is relatively little information on the taxonomy of foraminifera found in Saudi Arabia's Cenozoic formations compared with those from the Mesozoic formations. Four outcrops in the Al Lidam area, eastern province of Saudi Arabia have been studied to document the Miocene foraminiferal assemblages. Acetic acid was used to extract foraminifera from lithified carbonate rocks from 80 samples representing seven lithofacies. Results of disaggregation using acetic acid are promising. In total, 46 species of benthic foraminifera have been identified. The foraminifera are dominated by calcareous porcelaneous Miliolina (Coscinospira, Sigmoilinita, Peneroplis, Quinqueloculina, Triloculina), followed by hyaline genera (Ammonia, Cibicides, Discorbinella, Elphidium), a few agglutinated forms (Textularina), but planktonic foraminifera are absent. Borelis melo melo indicates that the studied formation is dated to Burdigalian to Langhian age. Based on the identified species, the studied formation is interpreted as having been deposited in an arid subtropical environment in hypersaline waters that were present on a restricted and very shallow carbonate platform (inner ramp). The foraminiferal faunas of the present-day Arabian Gulf show similarity with the Miocene faunas. Thus, the present-day Arabian Gulf provides a highly suitable modern analog for earlier Cenozoic conditions in the region.