Carbon and oxygen isotopes in nummulitide shells and limestones of the transitional Ypresian-Lutetian in the Crimean Bakhchisaray section. Paleogeographic interpretation

For the first time the ratio of carbon and oxygen isotopes in the large benthic foraminifera shells (Nummilites and Assilina nummulitides), Simferopol and lower Novopavlovsk formation limestones in the Crimean Bakhchisaray section have been analyzed. δ13C and δ18O variation curves have been constructed. It was demonstrated that the nummulitides and limestones. shells formation terms are reflected in their carbon and oxygen isotopic composition. Thus, the cooling in the early Middle Eocene was determined by oxygen isotope ratio shift changes in the nummulitide shells. Probably, this cooling was related to the registered global cooling at the turn of the Ypresian and Lutetian ages.