Rafidain Journal of Science

Abstract

Micofacies analysis and faunal evidence from the stratigraphic sequence of Sinjar Limestone Formation (Paleocene-Early Eocene) integrate three units accumulated in different zones on an isolated platform with bank-ramp depositional profile. These include: (1) a bank-rim buildup composed of red algae with subordinate coral boundstones, and interior bank dominated by nummulitic shoal-bar grainstone, (2) a backbank lagoon-bay of finer-grained carbonates punctuated by miliolids-alveolinids shoal bar and green algae, and (3) forebank rudstones-grainstones of red algal-coral and Nummulites. Paleoecological deduction point to a warm-temperate climate with colder periods during the overgrowth of red-algal bank which had not acted as effective barrier to water circulation. The genesis of the Sinjar carbonate bank can be expressed by alveolinids, miliolids and Nummulites as inner-middle ramp deposits of euphotic-mesophotic zone comprising foram shoals-lagoon-bay behind the domain of coralgal bank in meso-oligophotic zone.