Paleoenvironment and paleobiogeography of Lower Cretaceous carbonate successions of the northern Tethyan margin: Examples from Northeastern and Central Iran

Lower Cretaceous carbonate successions outcrop extensively along the northern Tethyan margin in Kopet-Dagh (NE Iran) and Yazd Block (Central Iran). These units are not well constraint terms of stratigraphic, sedimentological, geochemical, paleobiogeographic view point. To improve our knowledge, a detailed multidisciplinary study has been presented on two roughly coeval stratigraphic different areas, correlated with other tethyan carbonates. The (Taft Tirgan formations) have deposited shelf microfacies associations ranging from outer-shelf to inner-shelf settings. Diachrony ages at base top suggests long-term subsidence effects during Early Cretaceous, followed by Cimmerian phase epi-orogenesis, also remnant paleoreliefs. New biostratigraphic data coupled stable isotope δ13C records shows that onset production started much earlier than previously thought (Valanginian rather Barremian). Our results permit us correlate lower Aptian OAE1a. worldwide distribution index microfossils including benthic foraminifera colomiellids reported reconstructions. They used define provinces for Valanginian, Hauterivian intervals show predominant basin connections. Significantly, allochem content lithostratigraphic their phosphorus accumulation phases important heterozoan photozoan production, which recorded localities realm as consequence global paleoceanographic changes.