The mid- miocene climatic optimum (mmco)‎ manifestation in Iraq : carbon and oxygen isotopes proxies

Abstract EN

The present paper deals with the variability of the primary isotopic composition of seawater in the shallow water zone.

Sedimentary successions of middle Miocene outcropping in the eastern part of Iraq provide an excellent archive of the oxygen and carbon isotopes.

We analyzed the 8¹³C and 8¹80 to investigate the relationship between the lithostratigraphic units and the deviation of the stable isotopes.

The results show a significant relationship between the depositional energy changes and both 8¹³C and 8¹80 composition.

That displays the details of oxygen isotope events (Mi-events) and additional information about Mi2 and 3 zones, reflecting significant changes in the glaciation period, which have minor steps (interglacial period).

At the same time, carbon isotope maxima (CM-events) reflect changes in organic carbon burial and refine the Monterey Excursion.

Facies analysis revealed several microfacies could be distinguished, reflecting depositional environments including; supratidal and intertidal, lagoon, patch-reef, and open marine environments, matching with their isotopes storage differential, enhancing 13C and high rates of sedimentation in deeper facies.

The stable isotopes (180/160 and 13C/12C) provide an excellent archive of the Neogene (middle Miocene Transgression) 's paleoceanography for the Neo-Tethys.

Oxygen and carbon isotopic stratigraphy for bulk rock were analyzed to distinguish Monterey Event and climate optima.